Rod bender

rackI have a rack between the lathe and mill that holds mostly stock but also shared tooling. As is normal, it doesn’t hold enough stuff. But it has all these holes on the posts that are ideal for hanging tools from. So, just make a bunch of hooks and hang tools. Boy do I suck at that. I needed a bender if I don’t want to feel ill looking a bunch of noodles.

Enter another Tom Lipton project, the rod bender (plans at the link; Tom using the original on youtube). An excellent project in many ways, not that difficult but involves a bunch of machining skills: lathe, mill, welding, reading plans. It also a nice platform for adding to; I added a shoe and rod clamp. I was primary interested in bending 1/8″ [welding] rod and it tends to kink as the bend starts, clamping it prevents that. Kinking doesn’t seem to be a problem with 1/4″ rod (as seen in the video where I bend with and without the clamp). The clamp is also nice to keep long rods from flopping around while adjusting the bender. The shoe just replaces the fixed mandrels with a movable one, again it is mostly useful with small rod (the video shows both ways). The nose piece is chunk of 3/8″ endmill brazed in place.

Here is my implementation (not showing the rod clamp):
rod benderAnd in action:

chuck key holderI built this on the cheap, buying only a 3/8″ dowel pin and the bronze bushing (total less than $10). Made mostly from 1/2″ plate (Tom – remember Harry’s frame jig? it won’t do rear triangles anymore). The tricky parts were the three hole pattern for the bottom plate, there are three sets of holes (and two round plates) that have to match quite closely (technique here) and the pivoting arm, lots of machining: lathe (to turn 1/2″ plate into two pucks, that was a trick), ringwelding (two pucks into a 1″ puck), lathe (turn the puck into a tube), mill (make the mandrel block), welding (the block to the tube), lathe (turn the block to match the pivot boss), mill (drill holes) and welding (the lever stub to the block). I was really sweating the possibility of weld distortion buggering the tube fit on the bushing but it wasn’t problem.

Tip of the week – don’t assume that welding a broken tap will kill the temper, the tap just alloys with mild steel to make a new steel that is very very difficult to cut (had to get out the die grinder and grind it out).

Tip #2: The scale on hot rolled steel is full of oxygen (as is rust) which will raise hell if you are TIG welding; [this steel had really thick scale I couldn’t get off with a wire wheel] you get lots of splatter and a porous (like bread) weld that looks like crap. You can usually fix it with a lot of heat to create a puddle that will let the slag boil off but that can cause heat induced distortion. Much better to take the time to remove the scale before hand.

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2 Responses to Rod bender

  1. Tom Harper says:

    I saw a great photo of the Cinelli workshop in a Fine Art book. The caption waxed eloquent about the incredible artistry of Cinelli bicycles. The pic showed a workman bending the rear triangle into place with a long, stout, and well used stick. Hey, who needs jigs when you have a long bar?

    Nice looking bender. Looks handy. I might need one of these…
    -Tom

  2. Pingback: Mill vise stop redux | ZK Project Notebook

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