Looking For Expperienced Machinist ????

I am trying to thread a cold rolled steel rod, 1/2 inch in diameter with about 3/4 inch long thread. Have busted 4 different die holders, and find threading to be very difficult. (No broken dies - yet)

Wanting to know - is there a way to soften up the rod to make threading easier? I have no worries about hardness when done - but I have pretty much run out of local places to try finding a different kind of holders. :mad:

I was using a round die, and it kept spinning in the holder, and breaking off the point of the set screw. I just switched to a hex shaped die and it still seems like I am putting a big strain on the die and holder. After a bunch of hours (including return of the broken die holders) I have managed to thread approximately 5/8 of an inch - with three more threading to go.

!!! I am threading forward about 1/4 turn, then backing up about 1/2 turn, then forward again. Also using cutting oil - not motor oil. !!!

Any advice from you “metal workers” is appreciated.

Thanks, Dick

HI Dick,
I’m not a mechanical engineer, but it happen to tread some rods.
There are in principle 3 grade of Dyes generally sold as a complete set.
The technique I used was first to add oil lubricant and then to pass the 1grade dye with “alternate movements” and with small angles and advancing and pushing slowly for about half a turn and return. Clean with brush and applying oil lubricant again. Continuing up to the required length.
Next use grade 2 dye and repeat the same operation.
Next use the grade 3 dye, the final one, and repeat the same.
Don’t forget oil lubricant with a brush.

My remark, if I may, will be not possible to buy an already threaded rod ? here below a couple of links

http://www.fastenal.com/web/products/detail.ex?sku=0156384 from Minnesota


Hi Claudio - and thank you. I think I also agree to use threaded rod and will look today.

The rods (2) that I need are “L” shape and I wanted the threads only on each end. It is to act like an axle inside a small bicycle wheel. I am building a pedal car from wood for my youngest grandson (2 yrs old) and I was worried the threads inside the wheel bearing ( a sleeve) might cut into the sleeve when wheel is turning. Unfortunately, I will probably give up on threading myself, and just buy and install the pre-threaded rod.

Will keep a close watch to make sure the threads don’t cut into the wheel bearing sleeve.

Thank you again - Dick

Photo is what I hope the finished pedal car will look like - (or close to this).

Very Nice model ! Can the doors be open ?

Hello Dick,

Do NOT run the bearings on the threaded part of the bar !!!.
The threads will wreck the bearings in minutes.

Heat the rod ends where you wish to have threads, slowly to a blue heat, just as slowly let them cool down, do NOT cool quickly.
Have plenty of oil on the rod when you start threading it, cut into the rod about 1/4 of a turn, then turn the Die back to clear the thread.
Dont rush !, Softly,softly, catchee monkee !!.


Hey John - thanks for the tip. When I bent the rod (before the threading) it was obviously very hot (cherry red) and after getting my 90 degree angle bent, was quenched in water. :censored:
Hey - I’m a woodworker - I know epoxy and sawdust, not steel/blacksmithing. :stuck_out_tongue:

Will try to reheat the length where I want threads to a “Blue” color and then let air cool. I’ve tapped and threaded before, but was always on some steel that I hadn’t touched with my torch. Arrrrrgh … F I R E !!! (and I started my life as a tool & die designer for powdered metallurgy) Ohh Boy …

Hello Dick,

Heat the bends to blue as well, you may have hardened them, dont want them snapping do we??.


Yes Claudio - big argument with wife. I want only one side to open - she thinks both should open. You can probably guess who wins the argument! I am going to make a wooden crane that fits into the pickup box so it can look like a tow truck. Body for most part will be 1/8 inch Baltic Birch plywood, so I can finish most areas with varnish after a coat or two of epoxy. I did a mock-up set of templates from cardboard, but decided I needed to stretch the chassis a bit to look better. I also purchased some wire spoke tricycle wheels to replace the plain old steel wheels shown in the photo. This photo was taken when I first started. Needs window cut in back of cab, finish the engine compartment, add headlights and fenders and make the box in back of cab taller and longer. Before I can mount the wire wheels, I need to make the new axle pins - and then I can update the cardboard version and get new photos. Yellow strip at bottom is 1 meter long to give an idea of original size. By making chassis longer, the box can be bigger and the cab won’t look so tall.

Cheers, Dick

A mildly hopped up small block should work nicely.:smiley:

Hey Dick…

your screwed…

actually I have nothing to contribute, just wanted to drop a one-liner… LOL

Nice one Marc - actually the 1/2 inch steel rod is a new leading edge for a 50/800 Marblehead keel. The thread screws into the bottom of the hull, and then … :cool: :stuck_out_tongue: