Hello all. I was fortunate enough to attend Paul’s workshop in Chicago last week and learned a great deal, but the one thing I was unable to retain is what exactly the process is for fixing these missing (broken?) bushings in my riders.
As I understand it, there are taper pins holding the assembly together, but they’ve been smoothed down on the small end, so removing them isn’t simply a matter of tapping them out, right?
Paul also indicated that this might be a job for a local machine shop – any ideas where in Chicago might be a good place to start? What exactly should I tell them?
Lastly, once I get the assembly apart, how do I get the bearings into the rider roller?
I’m attaching photos to confirm the problem, but I don’t think there’s much mystery here.
I got everything taken apart, but even with the correct pin punch three of the four would not budge at all, so I ended up drilling them out very carefully. Ordered new taper pins from McMaster.
I got the bushings into the riders no problem, but they are a bit too small on the interior diameter to fit over the shafts. No damage to either though, so I’m just going to gently sand out the inside of the bushings until it fits over the shaft.
Thanks for all your help, it has been an interesting process (and it is much easier to polish the brass parts once everything is taken apart, so that’s another advantage to having gone through all of this myself)
The bottom, but measure them with a caliper, to see the difference. It is not great only a fraction of an inch. You need to be extra careful to get it all back together correctly ‘right round’ or you will ruin it.
So, be sure you double check with a measuring device before you start if the small and large ends are not apparent to you.
Make sure your pin punch size is exactly the small ends width and is, in fact, a pin punch – straight shaft without an increasing taper.
Just to be clear – the small end of the taper pin is the “bottom”, correct? Where it has been smoothed? Because of the smoothing, the two ends appear to be roughly the same size.
You can use a heat gun too, if fire is too scary.
I just did this exact job and I found that the bushing seats on the riders were fine and the shafts were okay too (after removing some rust and straightening).
Hooray for lesser metals!
Once you get it apart, measure everything with a vernier caliper and see if you get a variance. I was able to use bushings from a donor – I used the freezer/heat trick to install them like a piston wrist pin.
it’s not too hard.
The problem is that the riders and their shafts are now worn unevenly and the holes may need to be re-bored on a lathe, and bushings made to fit the new dimensions.
I don’t know what the originals were, but impregnated bronze bushings that don’t need oiling are a possibilty for replacement.
Removing taper pins shouldn’t be a problem if you use the largest pin punch that will fit, and drive out from the small end. Using a smaller punch or driving from the large end will be a big problem; either will deform and jam the pin in place. Then it will need drilling out, or sometimes a torch can be used to expand the material and loosen the pin. And those are best left to the experienced machinist.