According to the instructions for WNG’s plate perimeter bolts, it’s best if you use a magnetic base dial indicator to register exactly when you’ve raised a given bolt up enough to contact the plate. I happened to have on hand an inexpensive (~$20) digital snap gauge that I thought could handle the job, but clamping it directly to the rim was fiddly at best. Fortunately it has a conveniently placed hole in the back that makes it pretty easy to screw anything you like to it. Grabbed a scrap block of pine and voila:
Note that I knocked down the edges to avoid marring the rim, even though it’s already protected by thin cardboard. And here it is clamped in place:
(Actually it would have been a little better to clamp the gauge on the other side so I could get it as close to the bolt hole as possible. But I believe even this distance to be perfectly adequate given that none of the machine bolts were installed — if the plate is getting raised up it’s going to register just about anywhere nearby.)
I love it when a cheap, thrown-together tool modification works perfectly 🙂 I wouldn’t necessarily suggest going out and buying one of these particular gauges by the way. The annoying thing I’ve found about these cheap digital measurement tools is that they seem to eat batteries even when they’re off. So I have to pull the battery out or flip it around… kind of a pain in the neck. If I had it to do over again I’d probably at least try to get a dial gauge of some sort.
In Part II I clamped a mould into the oversized hole and filled the gap in with JB Weld. Now it’s time to clean things up and finish the job. First I gently bonked the top of the mould with a rubber mallet to break it loose — recall that I waxed it beforehand so this wouldn’t require much force.
That done I could just twist the mould out by hand.
Next, I cleaned up the excess JB welt with a double cut bastard file. I originally started with a finer file but found it gunked up too quickly. Even with the bastard file I had to clean it out repeatedly with a file card.
And here’s how it looked when I was done filing:
Just for the heck of it I did a quick surface prep and sprayed on some gold leaf to prove to myself the repair would look good when I refinish the plate.
Much improved, I would say! The dimple is from a spot where the epoxy sunk down a little too low — I’ll probably fill it in before the full refinish job, but it will be hidden underneath the washer anyway.
Thanks for reading.
In the previous segment, I decided to glue some dowels into small bits of plywood to create a mould for filling in the plate holes with epoxy. Next, the moulds got a coating of paste wax so the epoxy wouldn’t stick to them:
Now, how to get these things located exactly? The hole in the washers is too small for them to poke through, so I grabbed a cheap washer of the same size and reamed it out with a 7/16” drill:
Now I could line up this reamed out washer with the circle I’d drawn around the real washers, and poke the dowel through it:
Then, clamp the base in place:
So before I go mixing up epoxy, I try to get everything ready to go. As for the choice of filler, a “cold weld” epoxy was a pretty obvious choice (JB Weld is what I had handy). It’s quite strong, and will look good when painted over with fresh gold leaf. JB Weld has a pretty long open time, but it’s always better to be prepared. My main applicator was just a piece of stiff poster board cut to shape and gently folded down the middle. I also grabbed a small piece of steel (cut from a windshield wiper spring) for “detail” work.
With the pasteboard I could scoop up a glob of epoxy and let it flow down into the hole. The small piece of steel was useful for pushing the epoxy down into narrower gaps. At this point I also gathered up my safety equipment — disposable nitrile gloves, a respirator, and goggles.
I used a kitchen digital scale to measure out equal amounts of the two parts. Note that when mixing any epoxy it’s important to keep the proportions as exact as you can! Otherwise you end up with unreacted material and thus a weaker bond.
To be continued in part III.
Working on the rebuild of a 1911 6’2” J&C Fischer, I ran into a small dilemma – some of the plate bolt holes had been re-drilled at the factory (as far as I can tell), probably because the original holes were too far from the outer rim – i.e. the original bolt when drilled would have been too close to the edge of the inner rim, or stuck out altogether.
All in all not a big deal, but I’m replacing the original bolts with the WNG plate suspension bolts and the washer is a little smaller than the originals, so the enlarged holes were going to show. (They’re really nice washers, so I wanted to use them instead of the old ones.)
Unfortunately I had already drilled for and installed the WNG bolts before I realized this. I wasn’t too keen on trying to plug a stepped hole, so the question became how do I fill these guys in without losing the proper location for the hole? Since the washers are quite snug around the bolts, I could draw circles around the washers with them installed, like so:
I used a pencil here – not the most visible marking, but it showed up well enough. A black permanent marker would have been more obvious, but I didn’t feel like dealing with cleaning it off the washers…
I also had an idea that I could use dowels as mould so I wouldn’t even have to re-drill anything. All I had to work out was a way to get them in the right place…
The original unmodified plate holes were 7/16” and that dimension seemed to work well, so I glued some 7/16” dowel into some plywood cutoffs, making sure to keep them square to the base:
Continued in part II.
Welcome! I will be using this blog to share stories about my day to day work, and tips for technicians and piano owners alike.