DoAll Vertical Band Saw Pusher

[dgfoster]

I could not help it---once the drawing was finished all it took was loading the G-code into the printer and putting some black PETG on the printer.

Right Hand Side Top


Same Back.


The left side is the mirror image and is printing now.

The print is quite strong. It can not be as durable as metal. But I think it will last for quite a bit of use. Given the materials cost of about 10 dollars and the lights-out printing, replacement will be pretty easy if/when needed.

Handles will print in the morning.

Denis

 

[dgfoster]

I had a little time to work on this today. The handles were printed this morning with printed threads in the holes for mounting on 5/16-16 bolts inserted in the printed sockets for them. The plate is a press-in fit so that even without fasteners (tomorrow) you can pick it up by a corner and the parts stay together. A good fit here will help make for a strong and fret-free join of left and right sides. The handles feel very solid. I am leaning toward hand-peened aluminum rivets placed in countersunk holes as fasteners between the front and rear plates.




Denis

 

[Bill D]

I believe if a bandsaw has one of these fences and cable drive then it is called a "contour saw". Just a search term to maybe help others.
Bill D

 

[dgfoster]

Doall’s name for the “pusher“ is

5-013007 - WORK HOLDING JAW​

On their website essentially all of their vertical saws are referred to as contour saws.

Link: Do all Vertical Saws

Finding pics and information about the cable drive system has been difficult. Does anyone have a link to videos or pages describing the setup and operation of such a jaw and cable drive arrangement?

Denis

 

[Bill D]

I suppose you could place pins or clamp a stop onto the table so the pusher can not travel too far into the blade. That way it can be left to slowly cut by itself. Sounds like it could jam twist and break something.
I believe some makes use a hydraulic cylinder to control max speed of pull. Similar to horizontal BS. Some may even be hydraulic pump powered
Bill D

 

[dgfoster]

The prototype printed PETG pusher (work holding jaw) is finished.

Because this is a mashup of metal and PETG parts I learned an interesting thing along the way. Just like in casting iron you need to allow for shrinkage of PETG. It is less prone to shrinkage than any of the commonly used filaments but still shrinks .8% in the x and y directions but not the z direction.

When I made the hole table from my drawing and compared the hole locations I started spotting on one of the aluminum mending plates I noted a slight but consistent discrepancy and noted a proportional dimensional change in the mortise printed for the plate. That caused me to do a bit of reading and, sure enough, PETG is expected to shrink just the amount I noted in my print. So I transformed the mending plate, reducing it in size .8% and, voila!, everything was spot on.

This may not be a perfect pusher by any means, but it certainly is a useful enough tool and might serve as a starting point for someone else. In particular, no provision has been made for attachment of any cable or hydraulic system. But, in CAD that would be easy enough to do.

I happen to have an affinity for hand-peened rivets and they seemed well suited for this assembly, so... They do draw the front and back plates together securely.


The 5/16 bolt head fits snugly in its printed socket.


Denis

PS I am still curious about the drive systems used with jaws on contour (band) saws.

 

[M.B. Naegle]

The PM thread I linked earlier has some pics of the cable system. Otherwise the parts manuals for these saws have some OK pics, at least enough to recreate it.

 

[m-lud]

I thought it might be interesting/fun to draw something up that I could print in PETG in two parts and join using steel or aluminum plates for and aft. Rivets or countersunk-on-the-back flat-head screws could be used. Overall dimensions are 14" radius and about 10" height. I drew it 1/2" thick---it would be quite strong and the PETG is naturally fairly slick. If some moron (me) sawed it in half, it would take only a few hours print time to make a new one.

In my CAD program it would be easy to scale this up of down. I did make bosses for handles with countersinks for 5/16 bolts. And, yes I could not help myself when it came to the "eyes." Not sure if I would leave them in the print or not. ;-)

View attachment 395697
View attachment 395698

View attachment 395712

A couple of printed handles would complete it.View attachment 395713


Denis

The original, I like dg foster's posted version better.

 

[dgfoster]

The original, I like dg foster's posted version better.
View attachment 397262

m-lud,

Thanks for the endorsement of my pusher design. And, even more, thanks for posting the pic. Now, I see the reason for the sprocket teeth on the operator side of the original. That would be a clever way to have the pusher canted relative to the direction of cut while allowing quick engagement of the pulling cable system. I guess the cable system is controlled by a foot pedal. Using a
small 3-phase motor and a vfd it would be easy to have a potentiometer in the foot pedal just like the setup for a tig welder and have variable-speed control over the puller. That would take the misery out of cutting thicker stock while affording good control of material advancement.

Based on the paucity of responses I got concerning the setup and use of these devices, I have a feeling that not too many of these systems were actually made and used.

While my printed/riveted version is more rigid than many might guess, for such a pulling system, either casting or fabrication in metal a pusher would be the best option. Including sprocket teeth on the rounded back would be quite easy on printed pattern or pusher. And, on many filament printers printing my design as a single piece without a seam is very doable---Prusa's newly released and by all by all reports excellent, MK4 is large enough to do in one piece what I had to do in two.

Thanks again.

Added: m-lud, I can see you used some care to arrange the parts and provided a light background in your picture. Those extra steps made it so much clearer. Thank you for myself and on behalf of other members benefitting from that thoroughness.

Denis

 

[just Dave]

I had a big sheave about 6” thick and maybe 30” or so, that a customer wanted me to cut in 1/2/for a a mid shaft installation of some kind. A DoAll vert was what I had to work with it had the feed set up but the part was overwhelming for the man powered foot feed system. I used two one inch ratchet straps hooked to the back side of the table and around the sheave. The stretch of the band would maintain surprisingly evenly.
I have never been very impressed with the DoAll system of standing on one foot while run a band saw while using the other foot to run a backwards angled feed peddle. I push with my abdomen against a proper length board when needed. I generally use a feed in bandsaw.
dgfosters’ plastic pusher is cool if that is what system you already have.

 

[dgfoster]

I had a big sheave about 6” thick and maybe 30” or so, that a customer wanted me to cut in 1/2/for a a mid shaft installation of some kind. A DoAll vert was what I had to work with it had the feed set up but the part was overwhelming for the man powered foot feed system. I used two one inch ratchet straps hooked to the back side of the table and around the sheave. The stretch of the band would maintain surprisingly evenly.
I have never been very impressed with the DoAll system of standing on one foot while run a band saw while using the other foot to run a backwards angled feed peddle. I push with my abdomen against a proper length board when needed. I generally use a feed in bandsaw.
dgfosters’ plastic pusher is cool if that is what system you already have.

So, the drive system was powered by pumping action of the pedal? Or did the pedal control regulate a power feed system. I’m guessing the latter, but which was it?

Denis

 

[M.B. Naegle]

....
I have never been very impressed with the DoAll system of standing on one foot while run a band saw while using the other foot to run a backwards angled feed peddle. ....

While I've never used ours due to it's incompleteness, it was always my understanding that the foot pedal is only for resetting the feed? IOW, step on the pedal and shift it under the catch at the bottom while you arrange your work, not ride it through the cut. The counterweight inside is adjustable so if it's feeding too heavy you would lighten it up. Maybe ours is different, but the pressure of the feed is supposed to be automatic, as that's the whole point of it is to make it consistent and repeatable, not shift the job to another body part.

I think many of these saws had this system when new, but like lathe steady rests and other loose machine parts, they tend to get "put away" or otherwise separated at some point and then scrapped when no-one could remember what it was.

 

[dgfoster]

I wonder if it also means the drive/counterweight system was not particularly convenient. So, it got dusty on the back of a shelf.

Denis

 

[just Dave]

I wonder if it also means the drive/counterweight system was not particularly convenient. So, it got dusty on the back of a shelf.

Denis

That sums it up pretty well.

 

[just Dave]

If you ever use a feed in bandsaw, everything else seems ridiculous. For hand feed contour work I like those old DoAll pushers.

 

[rustyironism]

The Grob vertical saw I have is missing the cable system, but came with a stack of round weights to place on a platform to adjust the desired pressure.
Mike

 

[steve-l]

I commend the effort, I really do, but there is no way anyone can make this pusher at a lower cost than simply buying one from DoAll.

 

[Mud]

On mine the adjustable idlers are detached for clearance and the cables are left hanging behind the machine, nothing needs to be removed.


The footpedal lifts the weight off the cable. The catch at the bottom of the slot allows you to latch it in the down position to adjust and attach the cable. Usually someone leaves the machine with the pedal in the latched down position, then the next guy to walk past accidentally kicks the pedal, the weight crashes down and jerks the cables into the saw blade or worse. There is a handwheel to adjust the weight on the lever, closer or further from the pivot to adjust the force applied to the cables.

 

[M.B. Naegle]

On mine the adjustable idlers are detached for clearance and the cables are left hanging behind the machine, nothing needs to be removed.
View attachment 397544
View attachment 397545
The footpedal lifts the weight off the cable. The catch at the bottom of the slot allows you to latch it in the down position to adjust and attach the cable. Usually someone leaves the machine with the pedal in the latched down position, then the next guy to walk past accidentally kicks the pedal, the weight crashes down and jerks the cables into the saw blade or worse. There is a handwheel to adjust the weight on the lever, closer or further from the pivot to adjust the force applied to the cables.

View attachment 397547


View attachment 397548


View attachment 397549

Looks just like ours (what's still on ours at least). The main thing I need to make is the 5 pulley assemblies. The pedal, weight mechanism, and all the internal stuff I have. The most complicated part I see is the pulley covers that are meant to keep the cables in place when they are loose. I imagine they were stamped sheet steel, though I think I could turn them from a solid round and use a rotary table to mill the slots in the sides.

 

[steve-l]

Looks just like ours (what's still on ours at least). The main thing I need to make is the 5 pulley assemblies. The pedal, weight mechanism, and all the internal stuff I have. The most complicated part I see is the pulley covers that are meant to keep the cables in place when they are loose. I imagine they were stamped sheet steel, though I think I could turn them from a solid round and use a rotary table to mill the slots in the sides.

The parts you need are no longer available and have to be made. I made mine. It is no simple job. Do not underestimate that. I had extensive help from John Oder. His help was invaluable. He suggested to use aircraft control cable pulleys. I did. It saved a lot of labor. I made the cable shrouds out of aluminum. If you need info or dimensions, just ask.