Roll pin sizing question.

[jptbay]

Trying to fix the shifter in my plow truck.

Roll pin is missing from the 3-4 shift rail in the shift tower.

Measured the hole with a transfer punch. It's 7/32".

My stupid question is: Is a 7/32 sized roll pin meant to fit tightly in 7/32" hole?

Thanks all.

 

[larry_g]

http://www.engineersedge.com/roll_pin.htm

Your hole should be the nominal size and your pin is going to be a bit oversized to squeeze into the hole.

on edit, more information https://www.spirol.com/library/main_catalogs/sltp_us.pdf

lg
no neat sig line

 

[jptbay]

Thanks.

By that chart, a 7/32 roll pin should do the trick.

 

[Richard Cranium]

That will always be our guess also.

 

[ttpete]

For a much stronger pin, use a Spirol pin.

 

[kabinenroller]

You can also install the correct size pin then insert a smaller pin inside that pin. It will be stronger that just the initial pin.

 

[leg17]

That's the point of them.
The hole need not be precisely reamed, as for a normal dowel pin, but can be simply be drilled nominally and the same size roll pin, (technically spring pin), can be used.

 

[ChevyEFI]

To your question, yes.

The ones I use most are 3/16".
A drill that size fits the hole nicely.
And the roll pins are considered 3/16" in size.

Spirols are indeed nice.

 

[Provincial]

If you are concerned about the pin falling out again, use a piece of safety wire through the hole in the center of the pin and around the shaft. That way it can't fall out.

 

[jptbay]

Thanks again for the tips. Might try the safety wire. Was considering using some green Loctite 680 retaining compound on this pin.

 

[merr6267]

Loctite may or may not help you in the instance of a shift rail.
Retaining compound is generally for something that does not have motion between pieces. I'm not saying that it can't help, but I'd look at mechanical means too.

The "split pin" or "roll pin" will flex by very small increments with each strong shift. There is a spring to the fitment of the pin and with a strong shift the pin will shift very slightly and then return to form. THe retaining compound may eventually stop bonding with the bores as the spring pin flexes. The method of retention for these types of fasteners is due to the springy nature of the pin. They are chosen because they are forgiving of differences in bore and shape of the bore. If you were to try to use a solid dowel, you'd need a precision reamed bore and you'd have a very tight press fit.

If you can find them, true "roll pins" will be stronger than simple and more common "split pins" or "spring pins". See the illustration below.

http://www.mcmaster.com/#roll-pins/=10y8md0

The safety wire suggestion is great! Even just a simple loop through the center of the pin and tighly coiled around the fork and rail should do the trick.

good luck!

PM

 

[jptbay]

Ordered up some coiled spring pins. Thanks for the McMaster-Carr link.

 

[merr6267]

No problem. Good luck with the project. My plow truck is sitting and waiting for some snow . . . Mud season came early. Not that I'm disappointed with that.