Taper Pin Removal From 29K58

[BIGGUNDOCTOR]

OK, if I am reading it correctly, the problem child is the main pivot pin for the upper truss beam. I would be surprised to hear that that pin is a taper pin. You usually don't see pivot pins tapered, as the working action could pop them out. You will definitely need good back up, and watch out if there is side clearance on the frame to the beam. Too much clearance will allow the side ears to flex if stuck to the pin, and possibly lead to cracking. If there is a gap over say .003" wide I would stuff some shim stock in the gaps before attempting to drive the pin out. The shims will essentially make the assembly solid, and direct more force where it is needed instead of where you don't want it to go. I would suspect that the pins are tight on the frame, and the operating clearance is in the beam.

Too bad about the Kroil being $$$$$. Yep, there are tons of home remedies. I would suspect that the acetone in the ATF mix would evaporate fairly quickly, whereas the Kroil stays wet. I do know how well Kroil works though, as it has saved me some busted knuckles. I have over a gallon here at the house. Interesting that yu mentioned bore cleaning, as I have seen it at the gun shows here to loosen copper, and lead fouling in the barrels. Spray it in, let it sit, then use a tight fitting patch to push the fouling out. I also like the smell of Kroil.

Yet another method you might explore is one used to pop brake drums off of the old tapered axles. Put quite a bit compression on the end of the pin with a C-clamp type device that has room for the pin to move opposite the screw, then belt the end of the clamp screw with a hammer. Make sure that the C-clamp is backed up with your rail. The shock may pop it lose, then just press it out. I have some C-clamps made by Armstrong that are extremely beefy for their size, I don't think that a regular home use one would be stout enough though. You don't mention your skill level, or tools available to you. Being a machinist I tend to look at making tools as something easy to do, sorry if this is not an option for you. If not, do you have any friends who do machining?

[amuckart]

Hi Biggun Dr.

Thanks for your ongoing help. I don't know for sure that it's a taper pin in the 'k58, but it is in the UFA and the 'k13s. I don't have my caliper to hand to tell you the end diameters, but laying it on the table and putting a steel rule on it it's obviously not a straight cylinder. As far as this particular pin is concerned, it's tight on the beam and rotates in the frame on the 'k58. Looking at the wear on the one I've knocked out of the 'k13 it's the same there too; there's longitudinal scratch marks on the centre third of the pin and the outer thirds are smooth.

That's a good idea about the shim stock, I hadn't thought of that. The last thing I want to do is break the cast-iron frame of the machine.

If I'm visualising things right with the C-clamp idea you're suggesting using it like a whackable bearing-puller, yes?

If it helps scale your replies, I'd class myself as not stupid and basically mechanically competent, but I'm certainly not a machinist. I've stripped things like domestic treadle machines, a Pearson A1 add a couple of Junker & Ruh Sd.28s right back to individual screws and reassembled and timed them so they sew again, and I've taken my #6 Pearson down to minor sub-assemblies and reassembled it without a manual or leftover bits.

I have basically no power tools beyond a dremel, a drill and a poxy little belt grinder I've adapted for sharpening. I have a hand-cranked drill press kicking around in the garage someplace but I've yet to set up a bench to put it on. I can forge things on the scale of small knives, but I'm not trained or practiced in fine work and I have no formal mechanical or engineering training, and the last time I touched a metal lathe was getting on for 20 years ago. I'm mostly clever enough to ask for help before I break things, and I know enough to have worked out that I need a much wider range of screwdriver bits than I currently have I'm also not bothered by replies suggesting things I've already thought of, if it's not immediately useful to me, then it might be to someone reading the archived thread later.

All that said, I've a friend who's a volunteer steam engineer and tram driver at MOTAT who can put me in touch with real engineers who might be able to turn up small things in exchange for a case of beer if it's an interesting project.

[BIGGUNDOCTOR]

Your mate at MOTAT should be able to help out, as I am sure that they have dealt with their fair share of stuck hardware. I have read on the blacksmithing forum that "tinnies" are a universal currency in OZ, and NZ.

I like the fact that you are not afraid to tackle a job like this. Knowing how things work can come in very handy at times.

Yep, on the C-clamp. With the brake drum puller the screw is pushing against the axle, and the arms are bolted to the drum. As you run the screw down it tensions the drum outwards. When you whack the end of the screw it it sends the shock against the axle, and hopefully popping the drum off. I have never done it, but a way to pop tie rod ends is to whack opposing sides with a couple of ball peen hammers. The impact ovals the hole enough to pop the tapered pin out.

You might want to check out www.iforgeiron.com too , lots of folks down your way are registered up, and they are pretty active too.