How do I attach an Acme shaft to a handwheel?

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Forum topic by Rich Simon posted 09-21-2014 09:19 PM 3220 views 0 times favorited 9 replies Add to Favorites Watch
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Rich Simon

21 posts in 785 days

09-21-2014 09:19 PM

Bought a great heavy handwheel on eBay, 8” diameter, planning to attach it to a 1” (2 start) Acme shaft for a leg vise. So far so good.

The wheel has only a hex hole in the center, fairly smooth, measuring 38mm across its flat edges. Been walking through some ideas, looking at McMaster Carr, etc., but really not sure what the right way is.

Considered a set screw through the wheel and the rod, but it looks like the angle might be tricky to drill into the wheel (and it’s hard as heck). Thought about getting a 38mm hex nut, maybe with a flange, but then I’d need to get the Acme screw into it. Also, I don’t weld, or at least haven’t found a reason to (yet).

Mechanics, machinists – ideas?


9 replies so far

View distrbd's profile


2220 posts in 1866 days

#1 posted 09-21-2014 09:36 PM

View Dallas's profile


3599 posts in 1906 days

#2 posted 09-21-2014 10:02 PM

38mm is a tight 1.5”. Buy a 1 7/16” nut, insert and epoxy in. Epoxy the center of the nut, drill out and tap the center of the epoxy, thread into hole with a 1” nut and washer on each side.

-- Improvise.... Adapt...... Overcome!

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Rich Simon

21 posts in 785 days

#3 posted 09-21-2014 10:16 PM

I like the epoxy idea. Looking quickly though it seems the acme taps are more expensive than the acme rods!

View August McCormick Lehman III's profile

August McCormick Lehman III

1753 posts in 909 days

#4 posted 09-21-2014 10:35 PM

The only other way is buy a brass hex on eBay and just file it to fit your hex,.
The. Drill the brass to fit the acme shaft.
Coming from a wannabe machinist there is really no easy way to do it with out a lathe and a mill.
Or one more
Idea is have some one weld the acme over size and file it to fit the hex.
But getting it to line up straight is not that easy.
I made something like what your trying to do.
I have it posted on youtube


View Dallas's profile


3599 posts in 1906 days

#5 posted 09-21-2014 10:46 PM

I have a couple of friends who are master class machinists and fabricators. One even does old style forging to make parts for ‘Pop and Stop’ engines.

I have watched him make beautiful forgings of rods and bearing caps that cannot be distinguished from the original by eye.

I’m still wondering why you would actually need an 8” hand wheel, as a 4” would work nicely.
You could probably sell that one and buy a couple of smaller ones that were more useable.

-- Improvise.... Adapt...... Overcome!

View Dark_Lightning's profile


2619 posts in 2528 days

#6 posted 09-22-2014 01:57 AM

The wheel doesn’t have to be centered exactly in order to spin it. Grind the threads off the shaft; it doesn’t have to be perfect (though it would be nice to have the handle on the wheel not travel in and out while you turn it, so some care is in order). Then just get a piece of hex bar that fits the inside of the hex and has an ID around the OD of what you just ground off. Make sure that the hex bar is long enough (like 2”) that you can put a set screw in it (or just drill through and pin it) to hold beyond where the hex part is inside the hand wheel. Epoxy the hex-to-hex interface. Done.

-- Random Orbital Nailer

View runswithscissors's profile


2127 posts in 1444 days

#7 posted 09-22-2014 04:41 AM

Well, now you’ve found a reason to learn welding. I taught myself, and I love the way I no longer have to rivet and bolt stuff together. I’m sure a real welder would cringe at some of my “technique,” but it works for me. I make jigs and tool modifications that I wouldn’t even consider otherwise. I use a wire welder, by the way, and almost always use flux-core wire to simplify the process.

The way I’d approach your task would be to grind down the threads on the acme all-thread (as suggested above), bore out a nut that’s 38mm across the flats (or as close as possible), and tack weld it in place. To get the wheel to stay on, bore a hole endways, centering it right at the joint between the hex nut and the wheel. Tap it, and run in an allen screw. The wheel can’t pull off because of the threads. To remove, just back out the allen screw. I haven’t tried this, but I bet it would work. The same process would work to hold the bored out nut onto the shaft without having to weld.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View unbob's profile


692 posts in 1323 days

#8 posted 09-22-2014 08:36 AM

I would bore the hex out, make “on a lathe” and press in a steel bushing that fits the screw, then preferably drill and ream for a taper pin. Or, drill for a spring roll pin-there making the newly bushed handwheel a press fit on the screw also.
Having a bench with a leg vise and an end vise, I would be more inclined to use a 2lead screw on the end vise.
Since the leg vise has a shorter travel between having to set the leg pin, the 2lead screw travels very quickly.

View longgone's profile


5688 posts in 2728 days

#9 posted 09-22-2014 03:10 PM

I would take it to a good machine shop, tell them what you want to accomplish and ask what they would suggest.

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