new taper pin - how short to trim the ends after install?

[metalmagpie]

I have a machine where a biggish gear was only held on by a single 3/16" set screw. After cleaning and inspection, it turned out the gear had originally been fitted with a taper pin. The holes were buggered up a bit, but appeared salvageable. I ordered a used hand no. 6 taper reamer and a bag of new taper pins. They came yesterday and the hole reamed out easily with some cutting oil and the new pin drove in nice and solid. Of course, the pin sticks out both ends, maybe 1/2" on the big end and 3/4" on the small end. I am tempted to leave some of the pin sticking out at both ends just because it would make it so much easier for the next guy to both see that there is a taper pin and be able to tell which end is smaller. Normally this would be considered dangerous but it's in an area where it would be suicidally dangerous to stick your fingers so I think nobody ever would.

What do you think? Do I have to dress the ends fully down with a file, or can I leave a bit sticking out?

[CarlByrns]

On ag equipment, the standard for roll pins is to leave some showing proud so the next guy can see them. With a taper pin, I'd be comfortable leaving a 1/4 inch proud on both ends.

[mikey553]

The bigger end can stay sticking out a little. However I would cut the small end so it would stay below the surface. I don't know how it should be done, but I don't want the small end to mushroom for whatever reason and make it next to impossible to remove. Plus it would be easier to position a drift punch in a shallow hole.

[J Tiers]

leaving some outside makes it very easy to identify which end is the large and which the small. Unless it creates a hazard, which it does not seem to, I would do that, even though it is a little "untidy".

[BCRider]

I like Mikey's idea. It not only avoids any risk of mushrooming the small end but it makes it VERY clear which side is the bigger end and is hit to seat and which is the small and gets the pin punch for removing.

Mostly I think it's the idea that it makes things VERY clear as to which end is hit for seating and which is hit for removing.

I don't know about below the surface though. On thicker wall items? Nice idea. On thinner walled items I think we might want all the support we can get from the pin. But flush or just a whisker tall gets the idea across too.

[old mart]

I used to have great difficulty figuring which end was which when refurbishing old car kingpins. When I fitted the new pin after rebushing,I always cut the small end of the pin so that it was just below the surface after knocking home. Future work would have been much easier with a 1/16" recess for the removal punch.

[lakeside53]

To find the pin outlines if they have been ground flush, polish smooth both sides, then use a dye. Even Dykem diluted. you'll see them.
I like the pins that have a threaded hole in the fat- end. Dead easy to get out. My Polamco lathe had those.

[J Tiers]

Even when "buried" they still mushroom. When buried, they tend to jam, and are harder to fix. At least when sticking out you have the chance to deal with any mushrooming.

[ChazzC]

Even when "buried" they still mushroom. When buried, they tend to jam, and are harder to fix. At least when sticking out you have the chance to deal with any mushrooming.

Concur: if you leave a little of the small end out you can cut/grind it off to get a clean end to drive out.

[reggie_obe]

You could leave no doubt by stamping the gear hub by the large end of the taper pin with a B and the hub by the small end of the pin with an S.

[Mcgyver]

Has no one taken anything apart before? They are to my recollection always flush or just less than flush. Don't leave anything but the dome sticking out. It will mushroom 10x worse that way than in the hole. There is probably some safety aspect as well to not leaving them protruding (if a lot they could catch). The "correct" way to install is to have the hole the right size so the small end is flush or the dome is slightly proud. They are domed from the manufacture so can be struck and will still come out fairly easily. If you want a pro installation, clean up the hole with a taper pin reamer, size the pin, cut to length and file a chamfer around the end before tapping into position

[J Tiers]

Has no one taken anything apart before? They are to my recollection always flush or just less than flush. .........................

You are 100% correct. And those things are almost always a real pain to remove, in my experience.

Particularly with the very small ones, the diameter difference in the ends may be only a few thou. Try figuring that out on the smaller size pins, when the hole has gotten partly filled with dried oil that won't cone out, etc, etc.

Large sized pins are fine. Small ones are a pain when they are cut short and buried.

[Richard P Wilson]

New pins have both ends domed. When I'm fitting a new pin I usually end up having to cut the new pin to length, so aim for about 1/16" projection each end, but I make sure that I've domed the cut end. That way, its easy to tell which is the small end, and the doming makes sure that when hitting it with a punch, larger in diameter than the pin, it doesn't mushroom enough to prevent the pin being driven out. Doming also reduces the chances of the protruding ends catching and causing injury.