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View Full Version : Re-purposing a band saw



Bob Farr
04-18-2009, 05:48 PM
I've always admired the capabilities of powered planishers and english wheels, but welding up a big C-frame is too daunting and I'm short on space anyway. I ran across an old benchtop bandsaw with a sturdy cast iron frame and it seems to be the perfect size and strength for a small planisher or e-wheel. The throat is 14", it has 10" between the head and the table mount, and from the center of those points to the bottom of the frame arc is 10". Obviously it won't handle large automotive panels, but I work on motorcycles anyway.

I've seen the series in HSM on constructing the english wheel components, so I can just scale that down a bit. I think I would actually use a planisher more, but the conversion parts would be bolted onto the frame so I could build both and change as needed.

BTW, no vintage bandsaw components were harmed in this tear-down. It could easily be returned to sawing service. I thought I'd share a picture to see what other uses you guys could think of for such a frame. Any suggestions?

http://i58.photobucket.com/albums/g272/frankenglide/bandsaw2.jpg

hardtail
04-18-2009, 06:23 PM
Harp playing to the tune of nice score???????

doctor demo
04-18-2009, 08:32 PM
Bob, I am not an experianced sheet metal worker. Having said that, I'm not entirely sure that that frame would hold up to the kind of loads an english wheel would put on it. Of course I could be full of it too, but it would be a shame to bust it.

Steve

hardtail
04-18-2009, 08:48 PM
There is lots of criticism that the offshore wheels bought at places like HF and others flex under moderate loads, I don't know I don't have one but being cast and a bench model I would think it could work nicely for bike work.....I guess Bob will find out?????

tiptop
04-18-2009, 10:32 PM
I wish you luck with your endeavor Bob. I believe the bandsaw frame will flex to much for the forces required when used as an english wheel. The load as applied as a bandsaw are not only in the opposite direction vertically but the bandsaw has very little load axially. The guides and a sharp blade take them away. It might make it on the vertical load, you would just have to wheel more to get to where you want to be, but axially you will loose your pinch I believe. Now if you are just working say 22 ga. sheet metal it may do fine. I don't believe it will hold the wheels true for fender work. It was either at Metalmeet or Allshops, if you look into their english wheel files, someone had drawings that showed the loads. They are quite heavy to shape sheetmetal. To take out bumps may be a different story. An english wheel is not used just for removing bumps from planishing but to actually thin, bend and shape the tin. I hope I am wrong for your sake. Keep us posted on the wheel, they are fun projects.

Doc Nickel
04-19-2009, 02:07 AM
On a very similar note, a few years back one of our regulars over at the H.A.M.B. built a fantastic louver press (http://www.jalopyjournal.com/forum/showthread.php?t=134701) out of an old Oliver No. 173 Jig Saw.

http://i101.photobucket.com/albums/m79/kiwikevinp/IMG_2085.jpg

Now, while there's a lot of force involved in stamping louvers, the Oliver frame is pretty beefy, and can apparently take the load- though the guy says it flexes a bit when making a punch. Given the scale of that bandsaw frame, though, I kind of doubt it's as strong.

The forces needed to properly roll sheetmetal don't necessarily scale- meaning that, while you can use a smaller or higher-crown roller to reduce the force needed to deform the sheet, the high-crown rollers produce a smaller area of deformation.

Meaning you need to roll it more, with the tracks more closely spaced. Think of it as the difference between flycutting a 12" square plate with either a 2" face mill, or a 3/8" endmill.

In other words, if you use small-diameter rollers with a more severe crown, you can probably use this as a frame, but I still think you'd be disappointed with the results.

As a planisher? Maybe... some of the commercial "home shop" planishers that use those air impact guns have some pretty wimpy tubing frames- they basically just tap the ripples out of sheetmetal, rather than trying to mash it into shape.

I'd be kind of worried about the constant vibration perhaps cracking the cast frame, but I couldn't say whether that's a legitimate worry or not.

If I were you- and I've been thinking the same thing- I'd skip the repurposed frame and build one from scratch out of steel. Considering the overall size, and how much work you're going to have to do to repurpose the bandsaw frame, you really won't save much over using new steel.

Doc.

Bob Farr
04-19-2009, 08:58 AM
*** but it would be a shame to bust it. Steve

It sure would. Thanks for all the info and warnings gents. I think that air planishing loads are fairly light (I normally do it with light ball peen hammer taps) and I'll be working in soft aluminum to start with.

I do agree that the e-wheel loads needed to move metal don't necessarily scale down just because the machine itself is smaller. The PSI required to displace a given alloy are fixed, so my only way to compensate for the smaller scale machine is probably to reduce the size of the contact patch between the wheels. Of course, a small contact patch will take longer by requiring more strokes over the surface to stretch the metal, or it may simply mark the metal (a really low "bead" or crease) instead of giving a smooth stretch. Who knows until I experiment.

That louvering machine is really cool, and thanks for posting it. I also thought of making some adapters that use the arc of this frame just for vertical alignment rather than strength. For instance, a bushing in the overarm could guide a tap (tilting table still useful), a rivet die and anvil, or a punch hammered from the top. Look Ma, no more smashed fingers!

Langanobob
04-19-2009, 09:57 AM
Bob,

Somewhere (can't remember where) I remember reading that old bandsaw frames make very good English wheels. I think your frame looks more rigid than a lot of commercial wheels and for example makes the HF version that I have look like a cooked piece of spaghetti in comparison. It might be worth a call or email to our sponsor TinmanTech to get his opinion, since he designs and builds English wheels and of course is very skilled in their use.