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  • As some of you know, I have wanted to stop managing H-M for some time. It's a tremendous strain on my personal life. I want to set up my own shop. In September, September 15, to be exact, it will be 8 years that Hobby-Machinist has been in existence.

    I have been training VTCNC to run things here. Dabbler is going to learn too. I feel that they are ready to start taking over the operation. I will be here to help in case they need, but I don't think they will. Tony Wells is and will be here also to consult with. I will be doing backups, upgrades, and installing addons. Other than that, I will not be around. I am leaving this place in good operating condition, and financial condition.

Roll Pins & Shear Pins

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H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Jan 15, 2016
I'm re-assembling my 14x40 & doing some head scratching.

My lead screw had a steel roll pin in it. According the parts manual, its supposed to be a #3 1" taper pin (material unspecified). My picture is showing a stick of black nylon, not using it, just sizing the hole. Anyway I assume this is supposed to be a shear pin designed to fail before taking out the expensive driveline & a steel roll pin probably is too strong? Should I make one out of say brass? The shaft hole isn't the best job, I really don't even think its tapered, or maybe not any more. Once the pin is installed there is a sleeve that goes over & held with a single set screw. I guess its job is to contain the & make for easy replacemnt. Seems fine to me, remember this point for below.

Now the clutch cup. Here the manual calls for a 5mm steel roll pin (which it has). Its not going to shear because of the clutch spring/ball mechanism is designed to disengage long before that if torque builds up. But the roll pin is a PITA to hammer in & out. OK, somewhat aggravated a bit by tight working quarters, odd angle & the usual non-centered (hand drilled?) hole issue typical of these machines. But this got me thinking - why break out the pin punch kit & all that hammering? Why not drop in a nice fitting steel pin & make a similar low profile sleeve like the clutch? Am I off base?


Ulma Doctor

Infinitely Curious
H-M Supporter - Gold Member ($25)
Feb 2, 2013
Hi petertha,
you certainly can make a crosspin from brass or aluminum to prevent catastrophic failure,
just realize that it may need to be inspected more frequently.

the wonderful thing about having tools and a brain, is that you can do anything you wish to do!!!
if it sounds reasonable and you think it will work, try until it does work!!! :grin:


Mar 3, 2017
I'm re-assembling my 14x40 & doing some head scratching.

My lead screw had a steel roll pin in it. According the parts manual, its supposed to be a #3 1" taper pin
The "#3 taper pin" only has 1/4" taper per foot, it's possible that you have a reamed hole for a taper
pin that someone 'repaired'. You don't want any slop in that joint, so the taper pin sounds like
a fine choice to me. The pins aren't pricey, but if you need to re-ream the hole, it will cost
for a tool to do that.


Active User
H-M Supporter - Gold Member ($25)
Dec 20, 2012
The pin on my Emco Super 11 is made from aluminum. It is soft and feels like the hardware store variety aluminum rod. It should shear before a gear goes, or at least that is the intent.
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