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Homemade Portables Bandsaw Sawmill Progress And Questions :)

Started by Jay Sybrandy, September 11, 2016, 11:01:27 PM

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Jay Sybrandy

Hi  :)

I'm going to be making a portable bandsaw sawmill. It will be able to cut a slab 1200mm (4ft) wide and 8m long. The wheels will be old wheels off a mini they are 18.5" ( now im useing 27") diameter and will be powered by a 13hp petrol Kohler motor.(I have now got a 22hp Motor) We (me and my dad) will probably weld (silver solder) our own blades.

Here are some logs I will want to cut





Here is what I have designed so far




Here are some questions I have: ( The questions in RED haven't been answered and the answer will be in brackets next to the question)

- Will we need to have a way to tension the blade or can we just pump up the tires? ( Can just pump up tires but probably should put a way to tension the blade )

- Can I just use water for blade lube? (Diesel is better it erodes at the sap and doesn't rust)

- Do I need to lock the saw head to the carriage? I will have a hand winch lifting it and then will I need to lock it? (Probably should because if the wire breaks (5.5mm Wire Rope probably won't break) but still should )

- Do I have to lift the saw head on the return or can the blade just scrap on the wood? (Yes probably should because if it's pushing the blade up a little bit it will pop off the blade)


-Can I use green stickers in between my wood once I have milled it or do I have to use dry stickers? (Yes but not ideal)


- More will be added soon

What I am using/doing

Blade Lube: Diesel
Bed made out of 125x65mm Channel
Carriage made mostly out of 125x50x3mm Box section 
Blade Guides: Roller Blade Guides
Motor: 22hp Petrol


Here is my list of what I have spent so far https://docs.google.com/spreadsheets/d/1GpwtM4-dz2r4M73_X_YWPSkbwr4nfNiuKC6NIJb6lJk/edit?usp=sharing
Here is a Google Drive Folder of progress photos: https://drive.google.com/drive/folders/0B6NzuDmTB6DDY1ZQNWJFamR2VjA?usp=sharing

Here is what I have done so far (7/02/17)

I got this 125x65mm Channel for $10 a meter it had a little surface rust and little holes (6mm / 1/4") every 300mm 12". I had to fill them with weld and grind them flush and then buff them with a wire wheel on an angle grinder.



I then joined 3 channels and cut them down to 9.5m long, I welded 10 channel 1500mm long every 1048mm and then took it outside flipped it over and pushed it back in (didn't get photos of that)



Cutting all of those channels used a few cutting disks



Santa got me a length of 50x50x4mm box section, a length of 40x40x5mm box section, 4 lengths of 50x50x5mm angle iron and a 22hp V-Twin motor (Motor is still coming )




I cut a piece of that 50x50x4mm box section for my axle and drill 2 25mm (1") Holes 100mm (4") from the end to plug weld my stubs in

Here's a video of drilling the holes https://www.instagram.com/p/BOT429oAbHH/?taken-by=jaysybrandy



This is the drill I used to drill the 25mm holes



Pretty Colours





Wheels on



I then started on my draw bar. This is a bit of 75x75x5mm box section



Welded a bit of 80x10 flat onto the box section and added a gusset



In the other end, I welded a bit of 1" pipe for my pin to sit in



I welded my axle on. Those bits of box section extending off my axle are so my strong back can mount off there so it has a bit more strength :) 



I put 1/2 of the strong back on and added some cross bracing.

I'll get a better photo of the strong back when it's flipped back over tomorrow.


I used some 20mm solid round for some cross bracing



I put cross bracing in the other side and on the axle



Pulled it outside and flipped it over







My dads friend who is a linesman gave us these weird bolt things.



They are for holding the insulator to the cross arm the thread is M20.



I cut the end off and welded an M16 nut onto the end also drilled a hole to put a bit of round bar through and welded 2 5/16th nuts on the end to stop it from coming out.





I also sharpened the end a little so it can dig into the log.

I cut some 1" galv pipe to fit in between my cross members on my bed for my log clamps.
Then I cut some 1 1/4" galv pipe 100mm (4") long and welded a 100mm long bit of 50mm box section with a 14mm hole drill in the middle corner




The hole is for an M16 Bolt and the pipe will lock when pulled back by the screw (like a pipe clamp)



I welded 2 5mm end caps and an M20 nut to one of a bit of 50mm box section 700mm long





This is how the log clamp will work the long 1" pipe will be welded to the bed.



The hole in the box section will have a nut welded on it.



For the log dogs, I cut 4 more pieces of 50mm box section 700mm long with a 45-degree angle on one end so the log can roll on it smothley and welded a end cap on each end to keep the water out and so the log doesnt grab on it.



I picked up some M16 bolts and nuts also a 5" flappy disk.



I then welded a M16 Nut onto a bit of boxsection for the log dogs to sit in



And welded it to the bed of the mill I will have 4 log dogs and 4 places for them to go and 2 log clamps and 4 places for them to go.



Welded the pipe to the bed rembering to put in the bit with the boxsection welded inn it

Blury Photo :(

And it works !!



I might get a M20 Die to make the threads a bit longer.

I also welded the draw bar from the top side



My sister's boyfriend gave me 1m of Stainless M20 threaded rod and I brought one length for $59
I cut it into 8 pieces 250mm long





Then I drilled an 8mm hole in the end to accept a linchpin





Then welded an M20 Nut to one end so I can put a spanner on it and wind it down





The linchpin holds the foot on the way up and the nut pushes on the foot to lift the mill (probably should have put a washer in between the nut and bolt



The finished jack



I set the mill up perfectly level with a laser lever then made the angle irons level to that.





I had to join it in one spot



The wheels will run on the angle iron like this



I made 4 of these plates out of 5mm steel plate



And welded them to the end of the channel to stop the wheels (carriage) from falling off the end



Primed with grey primer







Then painted the main frame matt black



Then put the wheels back on



I will paint the jacks, dogs, clamps, drawbar and stuff a dark gray :)

To paint this I used about

4L of black paint  + thinners
6L of gray primer + thinners

To get the mill to this point it took over 130hr

Carriage :

I cut two pieces of 150 x 50mm (6 x 2 " ) box section 1500mm ( 5ft ) long for my carriage, then put 5mm end caps on them.





Then welded 2 60x10mm with 25mm holes in them for my V wheels



The other side of the wheel mounts unbolt and has a little ledge to hook under my bed so that the carriage can't fall over



I then cut 4 gussets and 2 pieces of box section 2000mm long for my uprights









I  also made 2 slides out of 5 x 50 mm ( 1/4" x 2" ) angle iron and 5mm ( 1/4 " ) plate



I bought a bandsaw blade for $105 from www.bandsaw.co.nz



I decided to use these bigger wheels that have an outside diameter of 700mm ( 27")





I will be able to get a little over 1200mm of cut

I backed my trailer part of my mill into the shed to work on my carriage



I then cut and notched a bit of box section for the top then welded it in



This was my first attempt at upside down welding (MIG)



I welded 2 braces onto the bottom and 2 on top to hold it while welding.



Lifted it off then welding in 2 corner braces





I then setup my saw head to weld in 



I then made 2 gussets out of 5mm plate and welded them in





I have decided to use larger 6 stud wheels that are 700mm ( 27" ish ) outside butI have already welded stubs to a shaft for hubs that I have, so I need to make some hub spaces.

I started by cutting 2 200mm (8") out of 12mm plate



Our circle cutting jig for out plasma couldn't go down small enough so I had to free hand them. To true them up I drilled a 16mm hole in the center and held it on a piece of threaded rod on our "New Lathe"





I then bored the middle out to be a tight fit on the hub and then drilled 10 holes 4 to line up with my hubs and 6 to line up with my rims



I then turned a lip to be a tight fit on the inside of my rim



I then drilled my hole out to 14mm then tapped them to M16 and cut then cut 20 pieces of M16 rod 40mm for stubs







I also made 2 pulleys for my lifting my saw head



For my adjusting wheel, I made a slide out of 5mm plate





Then made a mounting plate to hold my wheel with u bolts (I made those holes into slots)



I then welded on the mounting plate that will hold my wheel to the slide. With 2 nuts on top to tension the blade and 4 on underneath to track the blade.





The wheel adapters work well (after my uncle who is a machinist trued them up a bit.)



I also mounted the statinaie side





Starting to look wheelie good :)



I then started to make my blade guides out of 40mm stainless steel and 2 26mm bearings.









I made my motor mount out of 8mm plate and 125x50mm (5x2") box section with an M16 (5/8") blot to adjust the blade tension.









( will add another photo of the motor fully mounted soon )

I then started on mounting the system for lifting the saw head up and down. I am using 12 tooth sprockets and 1/2" chain (i think). In the photos there is an electric mobility scoter motor but I had to replace that with a worm drive gear box because the electric motor would free wheel. I made chain tensions for both ends of the chain to aline the saw head with the bed and to keep the chains tight.











Next, I started on the guards. I chose to use aluminum checker plate with an angle iron frame around it. The front of the guards will hinge upwards so I can change the blade.













Making large bandsaw sawmill - 15 Years old - NZ

paul case

We use only water on our bands for lube. It kinda depends on what you are cutting.

PC
life is too short to be too serious. (some idiot)
2013 LT40SHE25 and Riehl edger,  WM 94 LT40 hd E15. Cut my sawing ''teeth'' on an EZ Boardwalk
sawing oak.hickory,ERC,walnut and almost anything else that shows up.
Don't get phylosophical with me. you will loose me for sure.
pc

Kbeitz

Quote from: Jay Sybrandy on September 11, 2016, 11:01:27 PM
Hi  :)

I'm going to be making a portable bandsaw sawmill. It will be able to cut a slab 1200mm (4ft) wide and 8m long. The wheels will be old wheels off a mini they are 18.5" diameter and will be powered by a 13hp petrol Kohler motor. We (me and my dad) will probably weld (silver solder) our own blades.

Here are some questions I have :

- Will we need to have a way to tention the blade or can we just pump up the tires ?

- Can I just use water for blade lube ?

- More will be added soon


Check my Instagram for updates www.instagram.com/jaysybrandy

You better be real good at silver soldering.  It's tough to do.

Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Jay Sybrandy



You better be real good at silver soldering.  It's tough to do.
[/quote]

My dads a engineer so hopefully it will be strong enough
Making large bandsaw sawmill - 15 Years old - NZ

Kbeitz

The silver solder is special for bandsaw blades.
50N 50% Silver
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Joe Hillmann

]
Quote from: Jay Sybrandy on September 11, 2016, 11:01:27 PM
Hi  :)

I'm going to be making a portable bandsaw sawmill. It will be able to cut a slab 1200mm (4ft) wide and 8m long. The wheels will be old wheels off a mini they are 18.5" diameter and will be powered by a 13hp petrol Kohler motor. We (me and my dad) will probably weld (silver solder) our own blades.

Will the Mini tires and axles and bearings be able to hold the tension you need for a straight cut?  You want (on the low end) some where around 1500 psi strain on the blades.  If the blades are 1/16 thick then that comes out to about 1000 pounds of pulling but you need that on both the top and bottom of the blade so at a minimum each tire/axle/bearing will have 2000 pounds of force on it.  When it was in the car each tire had to support 1/4 of the car weight.  I went with heavy duty trailer tires and a 3500 pound axle/bearings and I don't think they are as strong as they should be.  My mill is powered by a tired 13 hp kohler and it does an adequate job.


Here are some questions I have : ( The questions in RED haven't been answered and the answer will be in brackets next to the question)

- Will we need to have a way to tension the blade or can we just pump up the tires ?


(My mill has no adjustment for blade tension.  When I order blades I tell them I need them 151 1/4 inches long.  I have noticed that some times some blades don't tighten as well or are too tight.  I assume it is because they aren't all the exact same length.  So you can build it without adjustment but it is probably better to built it with some adjustment for blade tension)  (no matter what you do need adjustment on both wheels of the tilt and toe in/out to get the tracking right)
- Can I just use water for blade lube ?

I use straight diesel.  All day cutting I may go through a gallon.  I squeeze a few drops onto the blade under the blade guide at the start of every cut.  Diesel eats up pine pitch, and in my experience water doesn't do anything but help cool the blade.  Also diesel acts as a lubricant and prevents rust,  Water left on the blade will cause rust by the next day.  If you do use diesel with rubber tires be very sparing with it.  If you get too much on the blade can start to float on the tires and pop off, that is why I do it when I am in the cut to prevent too much from diesel from sticking to the blade.


Do I need to lock the saw head to the carriage ? I will have a hand winch lifting it and then will I need to lock it ?

(Mine has no lock,  I had planned to build one but found it usually isn't necessary.  But one time my winch cable broke when I was cutting a log with the head up high.  Since the blade was in the wood when the head started to fall it couldn't and instead tipped over and the entire head fell to the ground doing lots of damage to the mill.  I ended up putting hooks on the bottom of the head that wrap under the rails so the head can't fall off again.  I also have solid stops at both ends of the mill to prevent the head from rolling off the ends.

- Can I use some hard plastic for blade guides and a bearing for the blade to push against ?

I used oiled oak for my blade guides.  It worked if I flattened and readjusted when the started to get out of shape which could be as quick as two full days of sawing.  I just recently switched to a set made of 608z or 608rs bearings.  So far it is working but I expect to have to replace them on a weekly biases but they are only  $0.30 each and swap out with one bolt so they are still easier than maintaining the wooden guides.  If I wanted to spend the money I would spend $400 on a pair of cooks blade guides and I think that would be the most hassle free way to go

Do I have to lift the saw head on the return or can the blade just scrap on the wood ?

If your machine cuts perfectly straight then you don't NEED to raise the head to return but at some point you will end up hitting the end of the log and knocking the blade off.  Since yours is a homemade mill there is a good chance the blade will rise slightly in the cut and when you get to the end of the cut the blade will drop and if you try to pull back without raising you will knock the blade off.  If you try to pull back with the blade spinning without raising it you will probably knock the blade off and if you don't have guards, send it flying and: if you do have guards, you will dull and kink the blade.

- More will be added soon




Jay Sybrandy

Quote from: Joe Hillmann on September 12, 2016, 10:00:25 AM
]
Quote from: Jay Sybrandy on September 11, 2016, 11:01:27 PM
Hi  :)

I'm going to be making a portable bandsaw sawmill. It will be able to cut a slab 1200mm (4ft) wide and 8m long. The wheels will be old wheels off a mini they are 18.5" diameter and will be powered by a 13hp petrol Kohler motor. We (me and my dad) will probably weld (silver solder) our own blades.

Will the Mini tires and axles and bearings be able to hold the tension you need for a straight cut?  You want (on the low end) some where around 1500 psi strain on the blades.  If the blades are 1/16 thick then that comes out to about 1000 pounds of pulling but you need that on both the top and bottom of the blade so at a minimum each tire/axle/bearing will have 2000 pounds of force on it.  When it was in the car each tire had to support 1/4 of the car weight.  I went with heavy duty trailer tires and a 3500 pound axle/bearings and I don't think they are as strong as they should be.  My mill is powered by a tired 13 hp kohler and it does an adequate job.


Here are some questions I have : ( The questions in RED haven't been answered and the answer will be in brackets next to the question)

- Will we need to have a way to tension the blade or can we just pump up the tires ?


(My mill has no adjustment for blade tension.  When I order blades I tell them I need them 151 1/4 inches long.  I have noticed that some times some blades don't tighten as well or are too tight.  I assume it is because they aren't all the exact same length.  So you can build it without adjustment but it is probably better to built it with some adjustment for blade tension)  (no matter what you do need adjustment on both wheels of the tilt and toe in/out to get the tracking right)
- Can I just use water for blade lube ?

I use straight diesel.  All day cutting I may go through a gallon.  I squeeze a few drops onto the blade under the blade guide at the start of every cut.  Diesel eats up pine pitch, and in my experience water doesn't do anything but help cool the blade.  Also diesel acts as a lubricant and prevents rust,  Water left on the blade will cause rust by the next day.  If you do use diesel with rubber tires be very sparing with it.  If you get too much on the blade can start to float on the tires and pop off, that is why I do it when I am in the cut to prevent too much from diesel from sticking to the blade.


Do I need to lock the saw head to the carriage ? I will have a hand winch lifting it and then will I need to lock it ?

(Mine has no lock,  I had planned to build one but found it usually isn't necessary.  But one time my winch cable broke when I was cutting a log with the head up high.  Since the blade was in the wood when the head started to fall it couldn't and instead tipped over and the entire head fell to the ground doing lots of damage to the mill.  I ended up putting hooks on the bottom of the head that wrap under the rails so the head can't fall off again.  I also have solid stops at both ends of the mill to prevent the head from rolling off the ends.

- Can I use some hard plastic for blade guides and a bearing for the blade to push against ?

I used oiled oak for my blade guides.  It worked if I flattened and readjusted when the started to get out of shape which could be as quick as two full days of sawing.  I just recently switched to a set made of 608z or 608rs bearings.  So far it is working but I expect to have to replace them on a weekly biases but they are only  $0.30 each and swap out with one bolt so they are still easier than maintaining the wooden guides.  If I wanted to spend the money I would spend $400 on a pair of cooks blade guides and I think that would be the most hassle free way to go

Do I have to lift the saw head on the return or can the blade just scrap on the wood ?

If your machine cuts perfectly straight then you don't NEED to raise the head to return but at some point you will end up hitting the end of the log and knocking the blade off.  Since yours is a homemade mill there is a good chance the blade will rise slightly in the cut and when you get to the end of the cut the blade will drop and if you try to pull back without raising you will knock the blade off.  If you try to pull back with the blade spinning without raising it you will probably knock the blade off and if you don't have guards, send it flying and: if you do have guards, you will dull and kink the blade.

- More will be added soon




Thanks !! Could I use waste oil ?
Making large bandsaw sawmill - 15 Years old - NZ

Joe Hillmann

Quote from: Jay Sybrandy on September 12, 2016, 04:16:01 PM
Quote from: Joe Hillmann on September 12, 2016, 10:00:25 AM
]
Quote from: Jay Sybrandy on September 11, 2016, 11:01:27 PM
Hi  :)

I'm going to be making a portable bandsaw sawmill. It will be able to cut a slab 1200mm (4ft) wide and 8m long. The wheels will be old wheels off a mini they are 18.5" diameter and will be powered by a 13hp petrol Kohler motor. We (me and my dad) will probably weld (silver solder) our own blades.

Will the Mini tires and axles and bearings be able to hold the tension you need for a straight cut?  You want (on the low end) some where around 1500 psi strain on the blades.  If the blades are 1/16 thick then that comes out to about 1000 pounds of pulling but you need that on both the top and bottom of the blade so at a minimum each tire/axle/bearing will have 2000 pounds of force on it.  When it was in the car each tire had to support 1/4 of the car weight.  I went with heavy duty trailer tires and a 3500 pound axle/bearings and I don't think they are as strong as they should be.  My mill is powered by a tired 13 hp kohler and it does an adequate job.


Here are some questions I have : ( The questions in RED haven't been answered and the answer will be in brackets next to the question)

- Will we need to have a way to tension the blade or can we just pump up the tires ?


(My mill has no adjustment for blade tension.  When I order blades I tell them I need them 151 1/4 inches long.  I have noticed that some times some blades don't tighten as well or are too tight.  I assume it is because they aren't all the exact same length.  So you can build it without adjustment but it is probably better to built it with some adjustment for blade tension)  (no matter what you do need adjustment on both wheels of the tilt and toe in/out to get the tracking right)
- Can I just use water for blade lube ?

I use straight diesel.  All day cutting I may go through a gallon.  I squeeze a few drops onto the blade under the blade guide at the start of every cut.  Diesel eats up pine pitch, and in my experience water doesn't do anything but help cool the blade.  Also diesel acts as a lubricant and prevents rust,  Water left on the blade will cause rust by the next day.  If you do use diesel with rubber tires be very sparing with it.  If you get too much on the blade can start to float on the tires and pop off, that is why I do it when I am in the cut to prevent too much from diesel from sticking to the blade.


Do I need to lock the saw head to the carriage ? I will have a hand winch lifting it and then will I need to lock it ?

(Mine has no lock,  I had planned to build one but found it usually isn't necessary.  But one time my winch cable broke when I was cutting a log with the head up high.  Since the blade was in the wood when the head started to fall it couldn't and instead tipped over and the entire head fell to the ground doing lots of damage to the mill.  I ended up putting hooks on the bottom of the head that wrap under the rails so the head can't fall off again.  I also have solid stops at both ends of the mill to prevent the head from rolling off the ends.

- Can I use some hard plastic for blade guides and a bearing for the blade to push against ?

I used oiled oak for my blade guides.  It worked if I flattened and readjusted when the started to get out of shape which could be as quick as two full days of sawing.  I just recently switched to a set made of 608z or 608rs bearings.  So far it is working but I expect to have to replace them on a weekly biases but they are only  $0.30 each and swap out with one bolt so they are still easier than maintaining the wooden guides.  If I wanted to spend the money I would spend $400 on a pair of cooks blade guides and I think that would be the most hassle free way to go

Do I have to lift the saw head on the return or can the blade just scrap on the wood ?

If your machine cuts perfectly straight then you don't NEED to raise the head to return but at some point you will end up hitting the end of the log and knocking the blade off.  Since yours is a homemade mill there is a good chance the blade will rise slightly in the cut and when you get to the end of the cut the blade will drop and if you try to pull back without raising you will knock the blade off.  If you try to pull back with the blade spinning without raising it you will probably knock the blade off and if you don't have guards, send it flying and: if you do have guards, you will dull and kink the blade.

- More will be added soon


Check my Instagram for updates www.instagram.com/jaysybrandy

Thanks !! Could I use waste oil ?

It will stain your wood and you can use oil from the bottom of the barrel because it is too thick.  I have used it when I was out of diesel and didn't want to run to the gas station.  It lasted about ten minutes before I decided it was worth it to go to the gas station.

Jay Sybrandy

I will use diesel then :) Thanks
Making large bandsaw sawmill - 15 Years old - NZ

ozarkgem

48" cut with 13 hp? I doubt that's going to happen. I had 18 HP and it would barely  cut 24" UP the HP if you can.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

Kbeitz

Maybe if you use 4 deg blades and run real slow. 
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Jay Sybrandy

I will only cut a few logs that are 4ft and if I go slow ? Because none in New Zealand sells 4ft wide slabs :) $$$$
Making large bandsaw sawmill - 15 Years old - NZ

Joe Hillmann

I missed the 4 foot wide part.  I think you won't be able to tension the blade enough using car tires to stop it from fluttering with that wide of a throat.  I think mine has about a 30 inch throat using heavy duty trailer tires and I have to inflate the tires until the rubber starts to deform around the blade to reduce the fluttering.

4x4American

I use green stickers all the time on portable jobs when the customer doesnt have any stickers off hand. 


To be proper, use dry stickers. 
To be quick, use green stickers.
To be quick and proper, cut up dry boards or 3/4 plywood into stickers.
To be bubba, stand the boards up against a wall.
Boy, back in my day..

Jay Sybrandy

Quote from: Joe Hillmann on September 12, 2016, 09:37:16 PM
I missed the 4 foot wide part.  I think you won't be able to tension the blade enough using car tires to stop it from fluttering with that wide of a throat.  I think mine has about a 30-inch throat using heavy duty trailer tires and I have to inflate the tires until the rubber starts to deform around the blade to reduce the fluttering.

I'll put a blade way to tension the blade :)

Quote from: 4x4American on September 12, 2016, 11:55:38 PM
I use green stickers all the time on portable jobs when the customer doesn't have any stickers off hand. 


To be proper, use dry stickers. 
To be quick, use green stickers.
To be quick and proper, cut up dry boards or 3/4 plywood into stickers.
To be bubba, stand the boards up against a wall.

Will the green stickers result in boards that aren't straight or not ? Can I use pine stickers :)

Thanks ! You guys on this forum are awesome !!
Making large bandsaw sawmill - 15 Years old - NZ

ozarkgem

Quote from: Kbeitz on September 12, 2016, 08:35:11 PM
Maybe if you use 4 deg blades and run real slow.
key words are maybe and real slow :)
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

Joe Hillmann

Quote from: Jay Sybrandy on September 13, 2016, 12:20:25 AM
Quote from: Joe Hillmann on September 12, 2016, 09:37:16 PM
I missed the 4 foot wide part.  I think you won't be able to tension the blade enough using car tires to stop it from fluttering with that wide of a throat.  I think mine has about a 30-inch throat using heavy duty trailer tires and I have to inflate the tires until the rubber starts to deform around the blade to reduce the fluttering.

I'll put a blade way to tension the blade :)



I don't think tires, even with a tension adjustment will be able to tighten up a blade with that big of a  throat.  The rubber of the tires may begin to warp around the blade before you get enough tension to stop the blade from fluttering.

Ox

I think you're right, Joe.  Something that wide would need pulleys and belts at the minimum.  Trued steel wheels would be best probably.

You can't be chincy at those widths and expect much good to happen.  :)
K.I.S.S. - Keep It Simple Stupid
Use it up, wear it out, make it do or do without
1989 GMC 3500 4x4 diesel dump and plow truck, 1964 Oliver 1600 Industrial with Parsons loader and backhoe, 1986 Zetor 5211, Cat's Claw sharpener, single tooth setter, homemade Linn Lumber 1900 style mill, old tools

Joe Hillmann

This post may look like a mess with lots of math and going back and forth between numbers and trying to explain why I used those numbers but I hope you can make sense of what I am trying to say.

I still think 4 feet would be too wide of a cut for a mill using tires but I will give you some numbers from my homemade tire mill that you can use to extrapolate to your mill.

My tires when aired up are 24 1/4" in diameter.  I find that they work best (on my mill) at around 35 psi.  The tires are 38" apart center to center.  With that spacing I could cut a 1" board 29-30 inches wide if I remove the blade guides.  If I were cutting 3" thick slabs the widest it would cut is 24"  The thicker the slab the narrower it can cut because of the curve of the tires.

The tires on my mill are 24" in diameter the if we assume the tires are in contact with the blade for 7/8" of the blades width(the blades are actually 1 inch wide at the gullets but because of the crown of the tires the contact is slightly less than that).  The mill has two tires but only half of the circumference of each tire is in contact with the blade .

To figure the contact area of the blade to the tires I will take 24"(the diameter of the tire)times pi(3.14) times 7/8" (the width of the blade in contact with the tire)  Which gives me about 66 square inches of contact.  That times the pressure in the tires (35 psi) gives me 2310 pounds of max stretch on the blade.  But that stretch is divided by the top and bottom of the blade.  So I have about 1155 pounds of strain on the blade which is well below the 1500 pounds that is the recommended minimum strain that should be on the blade.

I run my tires at 35 psi because if I go much above that the rubber of the tire deforms around the blade and takes the set out and bogs the engine.  But if I had a separate way to tension the blade I could run 60psi in the blades then tension the blade until the rubber starts to deform I would be able to get 2000 pounds of strain on the blade.

If I had that much more tension I could MAYBE add another 6 inches or even a foot to the width my mill will cut.  But to add 2 feet (in my opinion would really be pushing it).



I do know that If I have a blade that is a bit loose for my mill it will flutter a lot at full throttle but will flutter less at idle speed.  So maybe running a slower blade speed will help with a straighter cut.  This afternoon I will try making a cut with the blade at idle to see if it cuts well because if you are planning to cut that wide with 13 hp you will have to gear it down.



How often do you plan to cut 4 foot wide slabs?  By going wider you are making a machine that has to be bigger,  Will require more maintenance,  will require more expensive blades,  will probably require your blades to be kept sharper,  and probably won't produce as flat of lumber as a smaller machine.  If you plan of cutting lots of smaller lumber and only very occasionally cut wide lumber then I would recommend building a smaller machine that is easier to build and maintain and will cut average sized logs quicker than a wide machine.  If you really want to cut lots of wide lumber maybe a chainsaw mill is a better option.

I am not necessarily saying what you plan to build won't work I am just trying to point out to you where I think you may run into problems based on the issues I have had with my homemade mill.

Joe Hillmann

A couple other points.

  No matter how big or small the mill is the wheel that is driving the blade NEEDS to be pulling the blade through the wood.  It CAN'T push it through the log.

Also it is recommended to be aiming for a blade speed of about 5000-5500 feet per minute.  If you are building a regular sized mill with 13 hp I would aim for closer to 4000-4500 feet per minute.  If you are building a 4 foot wide mill with 13 hp then I would probably aim for closer to 2500-3500 feet per minute.

Joe Hillmann

I just looked at your plans on instagram.  I don't think that head will be sturdy enough.  You will probably  need another set of posts 2 feet or 18 inches behind the first with the tops tied together and lots of 45degree brackets bracing everything nice and solid.

Also you want something that wraps from the the bottom of the head down below the tracks to act as a hook so the head can't twist off the tracks.  If that happens when the head is up or the saw is running it gets dangerous quick.

If you have just a few large logs you can always quarter them with a chainsaw (the bar only needs to be close to half the width of the log) and wedges then mill the 1/4's on the sawmill.  You don't get the huge slabs but you gets lots of lumber out of them.

Joe Hillmann

Here is someone who built a wide cutting, small tire mill in 2012.  I don't know if he is still on the forum but you could try contacting him to see how it worked/ what problems he had. 

https://forestryforum.com/board/index.php?topic=61565.0

Although it looks like since then he bought a timber king mill then sold it so I assume that means it wasn't quite up the task.

Ljohnsaw

Quote from: Joe Hillmann on September 13, 2016, 12:07:19 PM

I still think 4 feet would be too wide of a cut for a mill using tires but I will give you some numbers from my homemade tire mill that you can use to extrapolate to your mill.
To figure the contact area of the blade to the tires I will take 24"(the diameter of the tire)times pi(3.14) times 7/8" (the width of the blade in contact with the tire)  Which gives me about 66 square inches of contact.  That times the pressure in the tires (35 psi) gives me 2310 pounds of max stretch on the blade.  But that stretch is divided by the top and bottom of the blade.  So I have about 1155 pounds of strain on the blade which is well below the 1500 pounds that is the recommended minimum strain that should be on the blade.

I run my tires at 35 psi because if I go much above that the rubber of the tire deforms around the blade and takes the set out and bogs the engine.  But if I had a separate way to tension the blade I could run 60psi in the blades then tension the blade until the rubber starts to deform I would be able to get 2000 pounds of strain on the blade.

Joe,
Thanks for doing the math ;)  I never thought about checking on mine to see what the tension is to stop the flutter.  I'm running 1.25" blade so your 7/8" contact is about right.  However, I'm using doughnut spare tires that run at 60 or 65 psi but they are a little smaller (22.5" dia).  They are VERY stiff and do not deform much around the blade for as far as I've dared to push the blade tension.  I just tighten until flutter is at a minimum.  So with your calculations -> 22.5 x 3.14 x 7/8 x 60psi = 3,700 lbs of tension (max).  But that tension is shared by the top and bottom sections of blade, so my actual blade tension would be half of that or 1,850 lbs.  My (designed) max cut is 42".  The 42" bed is just so I don't have to bibby down some monster logs.  I don't plan on splitting anything that big.  With 18hp gas and a sharp blade, I did a good job on some 30" logs.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Joe Hillmann

Quote from: ljohnsaw on September 13, 2016, 01:10:10 PM
Quote from: Joe Hillmann on September 13, 2016, 12:07:19 PM

I still think 4 feet would be too wide of a cut for a mill using tires but I will give you some numbers from my homemade tire mill that you can use to extrapolate to your mill.
To figure the contact area of the blade to the tires I will take 24"(the diameter of the tire)times pi(3.14) times 7/8" (the width of the blade in contact with the tire)  Which gives me about 66 square inches of contact.  That times the pressure in the tires (35 psi) gives me 2310 pounds of max stretch on the blade.  But that stretch is divided by the top and bottom of the blade.  So I have about 1155 pounds of strain on the blade which is well below the 1500 pounds that is the recommended minimum strain that should be on the blade.

I run my tires at 35 psi because if I go much above that the rubber of the tire deforms around the blade and takes the set out and bogs the engine.  But if I had a separate way to tension the blade I could run 60psi in the blades then tension the blade until the rubber starts to deform I would be able to get 2000 pounds of strain on the blade.

Joe,
Thanks for doing the math ;)  I never thought about checking on mine to see what the tension is to stop the flutter.  I'm running 1.25" blade so your 7/8" contact is about right.  However, I'm using doughnut spare tires that run at 60 or 65 psi but they are a little smaller (22.5" dia).  They are VERY stiff and do not deform much around the blade for as far as I've dared to push the blade tension.  I just tighten until flutter is at a minimum.  So with your calculations -> 22.5 x 3.14 x 7/8 x 60psi = 3,700 lbs of tension (max).  But that tension is shared by the top and bottom sections of blade, so my actual blade tension would be half of that or 1,850 lbs.  My (designed) max cut is 42".  The 42" bed is just so I don't have to bibby down some monster logs.  I don't plan on splitting anything that big.  With 18hp gas and a sharp blade, I did a good job on some 30" logs.

I should point out that math is very rough and but gives you some what of an idea of the tension you have.  I think the numbers are only somewhat accurate if the tire is starting to deform.  It also doesn't take into account the stiffness of the rubber which at very low psi's add to the pressure on the blade but at average or higher pressures probably reduces the pressure.

Jay Sybrandy

Thanks for all the help :) I might try find some steel or aluminum wheels.
Making large bandsaw sawmill - 15 Years old - NZ

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