Bandsaw Autofeed

[Brian Rupnow]

Last week when I was cutting some stock on my vertical bandsaw, I was thinking---"Gee---I wish I could just leave this and come back when its finished cutting, like I can my power hacksaw!!!"----This got me thinking---How hard would it be to rig a bandsaw autofeed. Hey--I do this kind of stuff for a living!!! So---Last night as I lay in bed, struggling with my insomnia. this is what I dreamed up. Very simple, but rather elegant. An arm, an adjustable position weight, and a couple of pivot points, I've shown a 1" thick x 3" wide x 6" long plate as the "Pusher" plate. One hardstop would be factored in to keep the pusher plate from cutting itself in half on the saw blade.---Brian

 

[black85vette]

Nice job Brian. Another cool invention.

I was wondering if you could also have some sort of guide system to keep the work moving square to the blade?

 

[Brian Rupnow]

Nice job Brian. Another cool invention.

I was wondering if you could also have some sort of guide system to keep the work moving square to the blade?

If the mechanism was built properly, without a lot of slop in the connections/pivot points, then the 1" thick bar would stay square to the table and to the blade. I know what you mean though---bandsaws are a bugger to "wander" in a cut. I don't think a setup like this would be terribly accurate, but for many cuts made on a bandsaw, accuracy isn't all that critical.

 

[joeby]

I am not knocking your design in any way, just a few ideas maybe.

One thing to think about is retracting the feed. You could fasten a lever on the side of your weighted arm to push down on and hold the feed back, and maybe also a catch to hold it fully retracted while you get the part positioned.

Maybe another way would be to use chains or cables to pull the block from the backside of the table. I've seen that sort of setup on industrial saws, (DoAll possibly?) which had a loop of cable with an end fastened to either side of the "feed block" and the loop going around a pulley which was pulled by the feed mechanism. That made it possible to "steer" while cutting. Some of those machines had a foot pedal on the front of the saw to release the feed pressure.

Others I've seen had a track down the center of the table driven by a hydraulic cylinder underneath; but this wouldn't be an easy modification.

Most reasonably built bandsaws can be made to cut accurately, but it takes patience to get the guides adjusted correctly and all the slop out of the upper guide. Good quality blades are also needed. A blade with the teeth knocked off one side or bad set will cut circles all day.

Kevin

 

[Brian Rupnow]

Guys--I'm probably not even going to build it. It was just an idea that I had. Sometimes a good visual representation of an idea will spur others into the knowledge that "Hey--Thats pretty simple--I could build something like that!!!".

 

[doc1955]

While working in the tool room before they purchased a band saw with power feed I use to take a piece of cable and just hang weights off the back of the saw. of coarse you had to stop short but it did solve having to stand and push. Back then we had a lot of bigger stuff that we needed to make rough profile cuts on and it on my arms and back. Its simple and doesn't cost much you can use about anything to hang the weights on I used cable because it was handy.

Brain I do like your concept you could move the weight from the fulcrum point to give you more or less pressure simple and neat.

 

[BobWarfield]

Brian, given your professional qualifications and the machine work I've seen you do, this is not ambitious enough!

Go to this page: http://www.cnccookbook.com/CCBlogSep2008.htm

Search for "bar feeder".

You will find this rather entertaining mechanism:

Be sure to play the little movie of it in action.

Cheers,

BW

 

[Brian Rupnow]

Bob---I use similar equipment on many of the machines I design. However, for use in my little hobby machine shop, simpler is better.---Brian

 

[Brian Rupnow]

Perhaps I'll go ahead and build one of these, just to see how well it works. Yesterday when I was building the "Table travel stops" for my milling machine, I had to sacrifice an old slide hammer I'd made about 35 years ago when I was doing a lot of custom auto body work to get the 1/2" shaft I need. I still have a piece of the 1/2" shaft left, and the slide which is a nice chunk of 2" diameter 1018 mild steel x 6" long---perfect for the "weight" part of the mechanism.

 

[Brian Rupnow]

Redesign time---I didn't like the way things stuck way out past the front of the saw table.--This tucks it in a lot tighter, and the "weight-arm" is on one side of the bandsaw only---still thinking---

 

[kvom]

At my school shop the manual "pusher" is a semi-circle with many small notches on the inside, allowing a piece to be held at an angle. That might be a useful mod to your design.

 

[Kermit]

Probably obvious and you've already planned on adding it, but

How about...

 

[Brian Rupnow]

Total change of direction this morning. Dark blue bar bolts across rear of the saw table, with 1" dia. x 7" long dark blue round bars on each side, below top surface of saw table.---17/32 holes through center of round blue peices. Bronze colored parts are 3/4" thick aluminum bars front and rear with 1/2" mild steel rods running between front and rear. Red peice at rear is a piece of bicycle chain running over a green mild steel roller, which is supported on outrigger off rear of dark blue frame.

 

[Brian Rupnow]

And with the pusher fence fully advanced up to saw blade---looks like this---

 

[rickharris]

Like the idea and the design development. If you were to put a clamp on the face of the moving element you could cut round bar without it revolving with the blade.

 

[black85vette]

More cool stuff from Area 51. :big: Like the new avatar. (not that we didn't like seeing you)

I like how this feeds straight and stops at the blade.

 

[chuck foster]

can you still get red bike chain??? :big:

looks good brian we expect photos of the finished autofeed by 6pm tonight :big: :bow:

chuck

 

[Majorstrain]

Hi Brian,
Great feed idea. Thm:

At work they have a band saw that the table moves towards the blade to enable an auto feed. It has an electric feed motor

Now that you are using slides in your design, you could just replace your fence with a table top. Mill T-slots in to it and you can clamp you work piece down to the moving table. It will be truly hands free.
All you'll need is a slot for the blade to run forward in (with reference to the moving table).
If you use a moving table their are no fences to get in the way of big work pieces and you can drill a hole though both the moving table and the original fixed table for a pin to lock the moving table in place when that function is not required. All you'll loose is maybe 3/4 inch in height with the extra table on top.

Anyway just my two cents worth in trying to make a simple idea more complicated. :big:
Cheers,
Phil