One of my longer term projects is a homebuilt motorcycle frame. To build one, I need to bend tube. So the next project is a tube bender. I’m use the free (yes FREE) plans over on the Chopper Handbook site. They call for the use of JD Squared or Pro-Tools dies. Now, the info in the plans may be getting on a bit, because the die sets are now in the vicinity of $400 for us Aussies, which is really beyond the budget of a home builder. If you can build a motorcycle frame, you can build the tube bender as well (that’s my theory, anyway). If you can’t build the tube bender or a frame jig, the bike project is probably a waste of time.
ANYWAY! Making the dies from steel requires a HUGE chunk of steel or aluminium and a CNC lathe or 4-axis mill (=expen$ive). Dave Gingery had plans for a tube bender using wooden dies. You can see his book here. I don’t have a copy of it but somewhere I heard about the wooden die option. There are builds of this type on the web already (see here for example). Also, my father has a wood lathe so I can get an “expert” to help me out. You could do it on a metal lathe but I’m going the easy option and getting some help.
Also, digging around in my steel rack shows I have some 16 x 75mm (5/8″ x 3″) bar stock, which is a fair bit larger than the 1/2″ x 2″ called for in the plans. But I don’t plan buying stuff if I can scrounge it.
So I am starting a build using big wooden dies and oversized steel frames. Hence the name – Mongo Tube Bender. Stole that idea from Gary’s build plans when he talks about scaling them up for bigger tubing.
First step was finding a chunk of timber big enough for the job. After a couple of stops at other timber yards, I ended up at Shiver Me Timbers. They deal in recycled timber here in Melbourne. Luckily for me they are only a ten minute drive away.
They found a block of ironbark that was plenty large enough to make a couple of die sets (1″ and 1.25″ is what I’m thinking). And they only charged me $60 (which I thought was okay). Here it is:
So yesterday I marked out the die profile on the timber twice, one each for 1″ and 1.25″ tube dies. From the top view, the profile is the same, so the marking out was the same for each die. I marked it all out in a 0.5mm mechanical pencil, even though it is hard to see in the photos, just to keep the lines nice and tight and accurate. Where a hole needs to be centred, I used my compass point to put a pin prick in the timber so I can centre a drill over it later. I went back over the centrelines and hole outlines with a Sharpie afterwoods.
The lathe faceplate will have to be screwed to the timber. Here is it sitting in approximate location:
The next step is to rough cut the dies out with my mitre saw. Dad can then bandsaw close to the lines and then spin them up in his lathe.