Another build thread... JoshNZ

[Magicman]

Might put a hole in the base to insert a screw driver if it ever needs to be cranked tight.

If you ever set the sawmill up in the places that I normally set up in there will be trouble.  Soft ground means that the outriggers very often sink a couple of inches before they stabilize.  Even then I very often have to crank them again after loading and handling a heavy log.  The pads are quite large and I carry an assortment of boards, but even then I usually have to crank them up and out of the accumulated bark, sawdust, and mud/dirt when the sawing is completed.  Just saying that I would not want the threads at the bottom of the outriggers.

[WV Sawmiller]

Lynn,

   And around here in winter those feet freeze in the mud and ice and you have to take a spud bar and sledgehammer to move them. Another good reason to have them sitting on the scrap boards and such as you describe.

[RAYAR]

Ahh that's interesting to hear... I suppose it is a lot of weight on a very small surface area. I wonder if you could lay another length of angle iron long enough for just the carriage on top of the tracks. With the ends ground tapered like ramps. Lay it on the track and roll your carriage on before transport. Otherwise you'll need a mechanism to lift it won't you.

I have something in mind to lift each corner of the carriage just enough to take the weight off the rollers, and therefore the bearings too after the carriage locking pins are in place. Still running other possibilities through my mind too at this time.

I'm also thinking about locking the saw head down too. It currently just rests where it bottoms out at its' lowest position.

[JoshNZ]

Might put a hole in the base to insert a screw driver if it ever needs to be cranked tight.

If you ever set the sawmill up in the places that I normally set up in there will be trouble.  Soft ground means that the outriggers very often sink a couple of inches before they stabilize.  Even then I very often have to crank them again after loading and handling a heavy log.  The pads are quite large and I carry an assortment of boards, but even then I usually have to crank them up and out of the accumulated bark, sawdust, and mud/dirt when the sawing is completed.  Just saying that I would not want the threads at the bottom of the outriggers.

That's a valid point  :-\. I could put a bit of a leg on the bottom of the thread too to get it off the ground. I don't know what else to do I'll be paying at least $100/ea for proper stands. It'll be half the cost of the mill unpowered hah...

I machined the replacement pulleys and new shaft today. Looks solid. Has anyone used biloc pulleys mated together like this? I'm wondering if I'll have to do something about the gap between them.. The belts will diverge about 5mm over a couple of feet. Premature failure might be the theme of this mill yet 






 

[JoshNZ]

I dragged the thing into town to fit belts, got a much better fit this time it looks pretty robust. Still need to trim the idler stud to position it under the first set properly.



 

I finally got around to adding a gauge to the jack. I drilled a blind hole in the bottom of it out of the way of any of the passages, and in an area where I could drill through the back plate it mounts to. Tapped that hole with a 1/8 BSP thread and then drilled a little 0.7mm hole on about a 45 degree angle, to join the cylinder cavity with the threaded cavity. The idea being if anything ever hammers the jack, the gauge won't explode in my face. I've tried wrenching on the jack lever and the gauge needle still moves slowly so hopefully it's about right.

Drilled an access hole in the back stop and then fitted it all up. I just need to build a bracket for the gauge but I think it's going to go pretty good. I had the hose made up in town, wasn't that cheap in the end. Hydraulics are nasty!



 


 


 


 

If anyone can be bothered doing the math... blade gullet is 26mm, 1mm thick. Jack bore is 24mm. I worked out I wanna be somewhere near 1700PSI. So I've been way overdoing it without the gauge. It'd be interesting to put a tension meter on the blade and see if it matches up there too, maybe there is force being exerted somewhere else in the mechanism.

What are the specifics to the measuring tension with verniers? Can it be done with a blade of unknown specs? Supplier couldn't tell me recommended tension let along specs.

I used a pretty similar idea for travel lock as above. I left 0.5mm between the tube/pins and it's still tight as hell after welding. Hopefully a bit of penetrating oil and time will resolve that problem. But other than it needing a whack to put in place, it holds it rock solid with no slop. The bolts are high tensile, 20mm.



 

Just got the feet to go now haha >:(

I think I'll use threaded rod from the hardware store and make it a top wind, with a drill or crank+socket. Just need to knuckle down on a good solid day

[Crusarius]

I like that lock plate alot. I may have to think about copying it. I would need to put it on the inside of the trailer though since my rail hooks would get in the way on the outside.

[Old Greenhorn]

Josh, regarding that gauge setup: That .7mm hole may be a bit small. Where I work we build hydraulic hand and power tools (up to 9,000 psi). We would only use a hole that small to control flow rate. For a gauge hole you may want to go bigger at around 2.5mm or so. You are seeing a slow response and this indicates the flow is restricted which will give you a lag while you are pumping it up. (also make sure you have the pocket bled out of all air)
 It is a little bit of a fallacy that hydraulics will 'explode' when something fails. The instant the pressure is released by expanding volume, it drops to zero because the oil is not compressed as air would be. The danger is when you have a small orifice that cannot release the pressure fast enough, then you have a powerful stream that can cause a lot of harm. So here, a bigger hole might be safer and give you better gauge response time.
 This is a small thought, I am just throwing it in. This build is going very nicely and I have been reading since you started, but never had anything to add. Keep on pluggin'!
Tom

[JoshNZ]

I like that lock plate alot. I may have to think about copying it. I would need to put it on the inside of the trailer though since my rail hooks would get in the way on the outside.

Can't see any reason that wouldn't work. If I did it again I'd leave 1mm tolerance inside the tube and not be so worried about slop, torquing the bolt up actually takes care of that anyway. If the hinge of your plate is set out slightly off the frame then the bolt sandwiching everything together will not allow any rattling.

Interesting greenhorn I thought I'd done it too big, only chose .7mm because the thinner bits wouldn't reach. When I say needle moves slow, im not sitting there waiting patiently for a reading, it equalises in a second or so. I'll see how it behaves, might bore it out to 2mm as you say when I tear it down for painting.
I thought if a lump of bark went under the band/wheel or something and wrenched the drive wheel in, the gauge might not feel that sudden pressure thump quite so badly.

[Hilltop366]

Too late now but a possible low cost source for a small hose would be a replacement grease gun hose.

High pressure and 1/8" NPT thread.

[JoshNZ]

Yeah, good idea.. I looked at brake lines too, steel/hose, I ended up talking to a guy at a shop in town who was super helpful, busy as hell but put everything on hold to work this out. We came up with an idea of adapters for the gauge and 350mm of hose and I could see it would work and I'd walk away with it in my hand and said yayaya blast it up, thinking price would be pretty insignificant. Blazed off to buy a 1/8" tap for another $50 or so, so not a cheap solution really hah. Scratching it all up to making the workshop more capable in future.

Actually with a 30 degree elbow adapter it wouldn't even need a hose, it'd peak out from behind the jack, under the beam. Just couldn't see it at the time.

[Old Greenhorn]

I thought if a lump of bark went under the band/wheel or something and wrenched the drive wheel in, the gauge might not feel that sudden pressure thump quite so badly.

Well I see your gauge is a good quality glycerin filled one and it is nowhere near being maxed out, so I don't think you run any risk at all on that score. As I said it's a nit. What made me even mention it is because if there is a lag when you are pumping it up, by the time you see your target pressure and stop, it may go above it when it catches up. I just saw that it might be annoying  is all. 
 Too bad you aren't just a tad closer. I have a handful of brand new high pressure (8,000#)jumpers at around a foot long with a 1/8" NPTF male on each end just laying on a shelf as spares for a purpose I do not yet even have. ;D I would have been happy to give you a couple. But you will likely be cutting lumber by the time they might arrive, I would even know how to do the 'customs thing'.

[JoshNZ]

Nah it's barely noticeable, just makes the needle a bit spongey which is perfect.

Yeah international shipping wrecks any chance of that but thanks for the thought! It amazes me the range, I once ordered a packet of ~50 brass hooks+rivets to replace one that popped off my boot, from China, for a grand total of $1.48 including shipping  :D :D. The total cost of 100 brass components + freight is cheaper than I can send a letter in an envelope back to them.
Someone in the US might want $45 for freight for a little bag alone  :

[JoshNZ]

I had a bit of space left on one of the threads so measured it while torqued right up and turned a brass washer slightly thicker. I guess this is a no-no supporting the gauge like this?

I would like to get an RPM gauge for the idle wheel too, to monitor band/belt slipping. Any searches here turn up 0-8000rpm tachos for cars what would I look at for a cheap 1500rpm tach?


 

[btulloh]

I see a lot of inexpensive tachs on amazon. 

Or - use an arduino, a couple sensors, an lcd, and have some thing that calculates and reads out as % slippage. Pretty simple to do. Any microcontroller could handle the job. 

[charles mann]

What about a tach from a farm tractor? They pick up off a wire on the alternator, so you could fab a bracket and mount an alternator for additional 12v power, plus the tractor tach.

[pineywoods]

I had a bit of space left on one of the threads so measured it while torqued right up and turned a brass washer slightly thicker. I guess this is a no-no supporting the gauge like this?

I would like to get an RPM gauge for the idle wheel too, to monitor band/belt slipping. Any searches here turn up 0-8000rpm tachos for cars what would I look at for a cheap 1500rpm tach?



Cheap tach for the idle bandwheel, $10 bicycle spedometer. A magnet glued to the wheel and pickup mounted to the frame.

[JoshNZ]

What about a tach from a farm tractor? They pick up off a wire on the alternator, so you could fab a bracket and mount an alternator for additional 12v power, plus the tractor tach.

That's an awful lot of installation for a tacho haha. I don't think I'll go LCD either I have those avr chips that you could program to measure slip% etc etc but I think just an analogue needle to scan, next to the tension needle, would be good.

I'll check out amazon

[Crusarius]

I love pineywoods idea. the bike speedo would be perfect.

[Fergy]

Google pressure gauge snubber 👍

[JoshNZ]

What is a decent log hook made out of? For the likes of this mill what length would I be after and what material should the handle be to be light/strong enough? Once again not that available here and not a cheap item to ship I imagine.

I still haven't found an analogue tacho with its own sensor in the right RPM range, anyone have a link?

[Crusarius]

Josh, did you look up bicycle speedometers? they can be calibrated to different wheel sizes.

[Ljohnsaw]

If you go the route of the bike speedometer, remember to mount the magnet more towards the center than the perimeter.  Out at the edge its speed passing the pickup is too fast to register.  I found that out on a 10 speed wheel.

[JoshNZ]

I can't find any bike Speedos that aren't a little glowing LCD Chinese looking p.o.s lol. I wonder if I could put a hall effect sensor on the shaft and generate a square pulse with a potted avr chip/circuit that any old tacho would read like an alternator.

I remember my other question finally, how long do bands last!? Not in bdft cause that doesn't make much sense to me but let's say 600mm/2ft diameter walnut logs that hadn't been drinking silica or anything silly, no nails... How many of them could you slab before you're needing to change? A ballpark figure i.e. 2-3 or 50? I have no idea.

[charles mann]

I can't find any bike Speedos that aren't a little glowing LCD Chinese looking p.o.s lol. I wonder if I could put a hall effect sensor on the shaft and generate a square pulse with a potted avr chip/circuit that any old tacho would read like an alternator.

I remember my other question finally, how long do bands last!? Not in bdft cause that doesn't make much sense to me but let's say 600mm/2ft diameter walnut logs that hadn't been drinking silica or anything silly, no nails... How many of them could you slab before you're needing to change? A ballpark figure i.e. 2-3 or 50? I have no idea.

could pull an alternator apart and harvest the components that would generate the pulse required and implement it onto your pulley shaft?
i asked a similar ? on blade life before and i can't remember who told me, or the BF he stated, but i think it was something around 350-400 BF, with several variables. hardness of the wood, how dry/seasoned the wood is, abrasive material (sand/dirt) embedded in the bark and so forth. but he did say, that was cutting an actual BF (1" thick, 12"wide, 12" long), so if you are cutting 2" thick, 24" wide and say 60" long technically, 20 BF but blade life count would be only 10 BF. your blades would last 2x longer than cutting a 1" thick board 24" x 60" x 2 boards for the same 20 BF, 3x if cutting 3" boards/slabs. yet you sell that material as 10 BF for the 1", 20 BF for 2" and so forth. at least if men serves correct, that is how he stated it.  

[JoshNZ]

Haha it's a bit of an odd thing to state blade life in BF you must admit =/. Like saying my cutoff saw disc will cut 3ton of steel before it needs replacing. But I get what you're saying. So, 2'wide x 8' slabs, only 25 of them best case? You guys must be swapping them every handful of logs?

I think the signal terminal on an alternator is just listening to one of the windings, via a diode. Half sine pulse. A lot of the alternator to take anyway I'm sure there'd be an easier way. I'll just keep an eye out a while longer.

I did a bit more sawing today, I'm having trouble with the idle wheel sleeve sticking on the beam, the gauge will leak down but the sleeve is still jammed there at full tension, happens unless it's freshly greased. I wonder if two rows of bolts in the back of the sleeve to act as jibs would be worth a go..? Or is that going to divot/dent the back of the beam =/