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Building my version of an SLR. (HELP)

Started by never finished, June 30, 2018, 01:03:11 PM

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never finished

 I have built a 30ft stationary fence. Put a two piece   belt conveyer in just under the fence. And installed an adjustable 10" rip saw, from a bell saw planer in between the two conveyers. I have a 2hp motor to power the conveyers and 5hp for the blade. I can easily get 3450 rpms on the blade. Is that enough? If so what speed do I need on the feed belt? I currently have a  2" sprocket pulling another 2". 9191 sprocket. 
 

 

 

 

Ljohnsaw

I like it!

For belt speed, I would think you either need variable speed or way overpower the saw so it won't bog down.

Will you be putting some pressure wheels (spring loaded) on top just to keep the boards from slipping?  I'm assuming your width of cut is somewhat easily adjustable...  Have you considered a splitter on the trimmed side to help keep the cut board running true/straight?

Now what you need is an air ram to pop the trimmed boards off the belt onto a parallel (lower) rack so you can run it one-man!
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.

Don P

We had a rip saw in one shop that had a long fence that was a length of 4"x1/2" flat plate. There was a pivot point near each end with some short pieces of plate connecting the bar to each pivot. The fence "swung" in or out and I could lock it in, the pivots made sure that it swung straight, you could add more to make the fence it more rigid. We had a power feeder angled just a hair in to the fence, you could do this with a little lead on the saw too I imagine. I would move right on, not as fast as a 20 horse SLR but at a good clip. On the gang rip we figured 5 hp per blade at 3450 and that seemed to work. It's been a long time I'd guess they were in the 100 fpm range but that's just a guess.

never finished

 I'm sure I used the wrong term with slr. What I'm trying to do is come with a better way than what I'm doing now. Table saw with a 18'long fence. My table saw runs a 1.5hp motor and this will run 5hp. It will be hard to do variable speed. I will have to change sprockets and chain. But doable if I have to. The fence is 3"x3"x1/4" angle bolted to a 3" channel. There are slotted bolt holes in the channel so it can be fine tuned when needed. I like the splitter idea but I have to make adjustable to move over with the blade. I have the conveyer  angled slightly to the fence. Right now it is running 91ft per min. which looks real fast compared to me pushing a board through the table saw. I doubt I ever reach a one man operation with it, unless I run it plum out of the barn. Pressure wheels are in the future plans. Would it help to hold the material to the fence if they were slightly turned into the fence?   

never finished

 Something that I left out is what I am trying to accomplish. I am trying to trim off the edges to a straight edge for my four sided planer. Logosol PH260. So generally the edging coming off will be less than 1/2". I have the book on the planer that says the normal feed rate for the machine is 12ft per min. But with an upgrade to a 5hp motor to go to 24ft per min. It isn't clear if that is for planer or ripping or both.    Thanks for all the help and please keep it coming.   

Ljohnsaw

This is JMHO, but...

Having the conveyor and/or the pressure wheels angled can either help or hurt the situation.  Take an extreme example - if a board has a lot of bend (crook?) in it, as it enters the blade, the rear is away from the fence.  As it passes through, the belt and/or pressure wheels are pulling the tail of the board into the fence.  The board is forced to rock around the blade and you end up with a still crooked board.

IF you have a splitter behind (past) the blade and it acts as a fence, the above pressures are pushing the board into the splitter (which keeps the board from rotating) and should give a straighter board.  The effect of the splitter keeping the board straight will improve the longer the splitter is behind the blade.  It would be easier to have the blade and splitter fixed and the main fence moveable. :-\

I would have the belt at a very slight angle and rely on the pressure wheels to be adjustable and do the pulling.  They would just be passive (non-powered).  Think old bicycle wheels - like from a very little kids bike - 12" or so.  Pick them up free off of CL.  With the wheel being bigger (then say a 4" caster), it will ride up on the boards easier as they enter.  Use the rear tire and the pedal crank as the mount that pivots for up/down.  Down pressure could be just a series of weights (like weight lifting plates) stacked on the frame or springs with turnbuckles.
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.

Ljohnsaw

Quote from: never finished on June 30, 2018, 09:04:04 PMSomething that I left out is what I am trying to accomplish. I am trying to trim off the edges to a straight edge for my four sided planer.
So do you already have a good, true edge running along the fence?  If that is the case, then your plan looks really good - ignore my concerns above.
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.

GeneWengert-WoodDoc

An SLR does not use a fence.  So, I do believe that you are wanting an ordinary, rough cutting rip saw.  

If I understand correctly, you have lumber that is not straight lengthwise.  This crookedness is the result of growth stresses in the tree or from reaction wood- -compression wood or tension wood.  All of these stress conditions mean that when you cut off a little on one edge, the remaining piece will actually warp a little as you also removed some stress when you cut off the edging strip.  To get a really straight piece, you need to cut a little off of both edges at the same time.  This saw is sometimes called a gang rip saw.

When using a fence, you need to decide if the fence will hold the lumber before or after it is ripped.  Holding before is an issue, as you do not have a flat surface full length.  Further, the crookedness May be more at one end, compared to the other end.  So, if you have a laser light and line the laser with the saw, you could align the lumber edge perfectly with the saw full length to put the blade where you would get a full length straight edge and not waste any wood.  To do this, we use a very thick saw blade, sometimes called a hogging blade, that will cut straight even when really close to the edge of a piece.  A thin blade near the edge will try to cut out of the wood by bending.  The alternative with a thin blade is to cut a thick edging strip, but 1/2" of an 8" wide piece of lumber is a 6% yield loss.

After the saw, we can use a fence on the outfeed, as we have a flat straight edge, especially if there is no stress in the lumber.  Prior to the fence we can use a belt conveyor, but we need to hold the lumber really tightly to the belt so the lumber will not move sideways, especially when the saw blade is cutting only one edge and the cutting forces are trying to slow down this one edge.  So top pressure-rollers are indeed useful.  If have seen many saws where the infeed conveyor is very slightly slower than the outfeed and the pressure to hold the lumber from moving is on the infeed conveyor.  The feed on the outfeed conveyor is often powered rollers and not a single conveyor, as you no longer need to hold the lumber so extremely tight, and the rollers are angled very slightly toward the fence.

The feed speed is often determined by using the idea that a rough cut circular saw will remove 0.05" per tooth for 4/4 - 6/4.  Much slower than this gives too much rubbing and heating of the blade.  So a blade with 28 teeth would cut 1.4" per revolution.  A 12' board (144") would take 100 revolutions.  At 3450 rpm, or 57 revolutions per sec, that is 2 seconds.  So, you might figure that you have too many teeth per blade or the blade rpm is too high.

I hope that these comments give you some ideas.  I encourage replies from you and others.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Don P

As far as rocking on the fence, I put the concave side to a long fence first so the board is riding on just the tips at each end, then flip and do the other edge. If you do remove stress you may need to repeat this process until the board calms down.

I've seen wheelbarrow tires on a rocker type swing arm with tension springs on the topside of the swing arm using eyebolts from the upper frame to the spring for tension adjustment.

I don't think you'd want a splitter and long fence together, I'm thinking with even a slight bow in the cut you'll get into a bind.

never finished

 ljohnsaw I do have a true fence that has a little adjustment if needed to keep it true. I have some WHMW plastic to put on the face of the fence so the wood will slide easier hopefully.
 DonP; Were on the same page with the concave side against the fence. I've had pretty good success with an 18' alum. fence clamped on the table saw. ( A lot of work). This contraption will hopefully make things easier and a little faster. I think what I might be looking for is what speeds people are running on their power feeds on table saws. Then I will desperately need help with the math on sprocket size. I have pics of a few projects that I have done. This is my third attempt at this post due to trying to put them in. Not to good on this machine with all these buttons.  I'll try to put them in a new reply. And thanks to all trying to help me figure out what it is I"m trying to do.  

never finished

 Trying pictures again. 80+ year old pine floor just finished this year.





t&g vertical siding and t&g lapp




t&g v groove ceiling and t&g bead board




erc t&g v groove ceiling

 

barbender

Too many irons in the fire

Don P

Good looking stuff!

We just got a feeder for the shaper and tablesaw, it runs 13,26,33,66 fpm. They have one at 78fpm. The ripsaws we used were running noticeably faster than the power feeders though, I think you're in the range enough to give it a try.

Sprocket math is easy, divide the tooth counts and multiply by the motor speed. For example if you have a 12 tooth sprocket on the motor and a 48 on the conveyor, 12/48=.25. Multiply .25 x 3450=862.5 rpm

Crusarius

Can always use a VFD to adjust the speed of the motor (electric motor). I actually just learned about this for my drill press. Instead of changing the belt pulley's you can just adjust the VFD to change speed.

Last VFD I bought was $80 it also acted as a 3 phase converter.

Ljohnsaw

Quote from: Don P on July 02, 2018, 06:16:52 AMSprocket math is easy, divide the tooth counts and multiply by the motor speed. For example if you have a 12 tooth sprocket on the motor and a 48 on the conveyor, 12/48=.25. Multiply .25 x 3450=862.5 rpm
And then divide by the circumference of the roller (3.14*diameter (in inches)) and then divide by 12 to get FPM.;)
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.

never finished

 The VFD sounds interesting. I'll look them up and see what I can come up with. Will they work on any electric motor? That probably wont be much more than sprockets.
 I don't have the shaft speed. It goes through a gear reducer. I'll dig around and see if I can find it in the manual, or on a plate. I got the conveyers and some roller tables off a demo job a few years ago. Printed a manual off the net but it's up at the barn. I got my speed by using a measuring wheel and stop watch. Done an average of several runs. Thanks guys.  

YellowHammer

I have a power feed on my table saw, and also a SLR and seem to like about 80-90 fpm for both.  That speed is about what I can start feeding a board in the machine, let it go, reach and grab another board, set it in place and feed it in.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

mike_belben

Industry is full of applications like yours that would benefit from forward and reverse capable and varispeed drive.  In my "career" i have found that dayton 0-90vdc reversible controllers and gear motors are the standard.  Ive worked around many of these and own a few.   

Hopefully this link works, its a controller for $150

Dayton DC Speed Control
Praise The Lord

YellowHammer

One thing that I haven't heard mention is anti kickback devices or catch bars for the strips.  My SLR has three lines or walls of anti kickback teeth, and for good reason.  All board edgers also have significant anti kickback devices.  I've rarely entered into a conversation with someone who had an SLR or edger that doesn't know someone who got speared by a thrown edging, or had been saved from injury from the anti kickback devices. 

The boards are generally held firmly to the belt or caterpillar track with pressure rollers, but the kick back happens when a narrow edging gets released from the board on the exit cut, and since its relatively lightweight it doesn't grip the conveyor, and also since its lightweight, the spinning saw blade throws it like a ball from a pitching machine, generally into someone's leg or hand.  My SLR has its kickback teeth arranged in rows, like walls or shields, to either catch the piece or physically block it from coming out.  
On my table saw, with a powerefeed, I had a piece of edging fly maybe 40 feet, and actually go out the open door of my shop.  I always made it a habit to not stand in the line of fire so I watched it whoosh by me. 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

never finished

 I looked at the VFDs. Problem is I have a new 2hp 1phase motor. I do have a 3/4hp 3phase motor but not having a lot luck on VFD at a reasonable price. And I'm not sure that would be enough power for 30' of conveyer pushing a 12' board through a saw.

Mike_belben will a controller like that work on a 2hp 1phase motor? If so I'm all in.

YellowHammer  Thanks you just saved me. I haven't thought much about kickback. I'll study on that. Maybe some hanging chain like we put on brush hogs for the strip, and fingers for the board?  I will probably have pressure rollers.  Might have to go with a suit of armor. I will for sure be in the line of fire of the cut off strip. I can't move to the right at all. My speed is close to what your talking about now. It looks like the speed of light to me. But here lately I have been pretty slow in this heat.
  Thanks and please keep it coming.  

mike_belben

No youd have to pair it with a 0-90v DC reversible gear motor. New theyre pretty spendy, $300-600.

All conveyors ive worked on that used electric motors were running a gear drive, usually right angle worm style like a braden winch.  Ive seen between 20:1 and 200:1 ratio depending on application.  boston gear was a common name for those. Surplus center probably has a bunch of them.

 You can run a VFD on a single phase motor.  Youd need a 2hp rated vfd with 1ph input to 1ph output.  
Praise The Lord

Crusarius

you can run single phase VFD's they do not need to be 3 phase. Checkout youtube for VFD drill press. That will at least give you some info and show it can be done.


Edit: I missed mikes post, I agree with him but think you would want 3hp VFD to match the motor.

mike_belben

Hes got a 2hp motor.  Definitely wise to run a bigger vfd vs a smaller one than needed.  

Just beware vfd can only overspeed or underspeed a percentage. Youd have to push off to stop the conveyor (and i dont know how happy they would be getting E-stopped.  Maybe lose presets? No clue there)

 zero to 90vdc controllers can go from stall to full speed and anywhere in between by turning the dial.  Wont mind an E stop at all.  


Just things to consider.  Could you put a temporary hand crank on this edger to test it out in wood and video the pulleys with marks to count rpm?  Thatd give you an idea on gearing and personality so to speak. Figure whether youre gonna be flying wood through or needing slow and high torque with a top tension roller.  

Btw sprockets with blunted teeth on a weighted floating arm riding over the top of the planks would probably help keep things tracking straight and maybe reduce kickback.   Bicycle sprockets have a one way clutch that would let wood feed in but not fly back out.

Praise The Lord

Crusarius

oops he did say 2hp. I dunno where I saw 3 hp? maybe I was thinking of my vertical mill?

The videos I have seen on the VFD with the dial you can go to stop or full speed.

mike_belben

Well, there you have it.  Technology improves fast.  Ive used one or two but theyre probably ten years back tech by now.
Praise The Lord

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