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Tapered pin removal methods

dinotom

Aluminum
Joined
Oct 25, 2016
The knobs on my access doors are giving me a bit of a headache
I was able to get two of the pins out on the knob side (1 from each access panel door) Those were bit situated where the smaller side was on the latch side of the back part (the cam latch), meaning the pins was in the middle of the cam. They both came out relatively easily. The other pin on each knob are not coming out and I've bent two Starrett drive punches trying.

Am I making an incorrect assumption that given how the other two pins were in the hole the other two should be the same? It certainly appears that I'm driving out the smaller side. I've tried from the other side as well, even if to just loosen the driving from the other end.

I've tried pressing them out on the press but they aren't conducive to holding properly. I'll probably build a jig to hold the doors properly for this operation if I cant drive them out normally.

I've used Kroil on them for two days. I'm going to try heat but I'd prefer that as a last resort.

These are the pins I'm referring to.

10EE_KnobsonAccessDoor.jpg

And don't get me started on the pins on the latch side, none of them even think about moving
 
Sometimes the small end gets a bit peened over and starts looking like the big end. File it down on both ends and compare each to the end of the punch you want to drive it out with and you can find the smaller end.
 
One of the oldest tricks in the workshop to getting things unstuck is, heat and Bees Wax.
I would heat the parts with a propane torch until the Bess wax freely melts into the joints, may take a couple of heat-wax cycles,but the dissimilar metals should break free from uneven expansion, the wax will follow the heat, go through corrosion, and locktite.
 
Good tip Donie.

I also suggest you just can not put enough effort in discerning which end is the small end and which is the large end. If you start whacking on the wrong end you are digging yourself into a deep hole.

I was able to get my door knobs all off and when I was done I was surprised how beat up all the old taper pins were. I fitted new ones for most of the applications.
 
They usually come out relatively easy. If working on one side doesn't produce any release, try to push the opposite side instead. It's not always easy to discern between the small and large ends of a used pin.
Keep the punch parallel to the pin.
 
Another thing to consider it that the holes for the tapered pins were drilled and reamed by hand with the knob, or whatever, in place on the machine. Odds are, that if one side makes that easier, that's the big end. For example, you can bet that the knobs on the quick-change gearbox were drilled and reamed from the top.

Cal
 








 
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