A little advice on bushing

[hugha]

Having just installed several new bushings into my current Jerome/New Haven project, I would like to have advice/opinions on fitting the bushes into the movement plates. Since I don't have a lathe (yet...) and my set of reamers goes up to only 3mm, I'm limited by standard twist drill sizes and sometimes brass bar stock sizes. Result is that sometimes the bushings are a loose fit, so I have been gently peening them to get the required interference fit. It seems rather crude but the end result looks and works OK.

Opinions and advice (be gentle) welcomed.

Hugh Aston
Christchurch
New Zealand

[R. Croswell]

It's the end result that matters. Peening is one way to tighten a bushing. If you plan to do bushing work by hand, I would suggest that you consider getting an inexpensive set of bushing reamers and some standard size bushings to match.

Bob C.

[shutterbug]

Personally, Hugh, I prefer smaller bushings and reaming them to fit. I often use the 3mm size bushings, and less frequently the 3.5mm, but larger that that is quite rare. I'd suggest that you get reamers for the 2.5, 3, and 3.5mm sizes and use them instead of trying to drill. If you do drill, use a drill press and clamps (for reaming too) and a drill about .03mm smaller than what your bushing is. Get a good set of small cutting and smoothing reamers for adjusting the inside hole to your pivot.

[Veritas]

Like Shutterbug i do not drill my bushing holes when i bush.For someone starting out this not a easy thing to do.A twist drill will grab and spin the plate.Which could result in personal injury and also a enlarged hole that will re quire a bigger bushing or maybe even a plug installed.I don,t usually go larger than the 3.5 mm bushing.

[Mike Phelan]

Hugh
I have never used commercially made bushes, but I usually use a broach, rather than a reamer, for normally sized clock holes. This gives a slight taper, IMHO better than a parallel drill hole. I always just press bushes in.

For bushes larger than my largest broach - barrels and the like, a file tang makes a good broach, as does a worn out square file with the teeth stoned off!

HTH

PS:A twist drill will grab and spin the plate
Veritas
I try to use a separate set of drills for brass, and stone the rake off the ends of the flutes so they are parallel. As you would do with a lathe tool for brass.
No more grab. That is why spade drills are so good in brass.

[Willie X]

h,

Assuming that you have 'broaches' that go to 3mm. That should do for most work but I would consider buying one more broach that would go up to about3.5 mm and purchasing at least three packs of standard sized busings. For my use I would stick to the KMW sizes. With a small round file and the proper use of the hand broaches, you can do good work.

Using regular drill bits will not maintain the original center and the resulting hole will not be round.

If you do come up with a bushing that is 'loose' be sure to chamfer both sides of the hole slightly before peening; this is especially important if you plan on dressing the bushing flush with the plate.

Good luck, Willie X

[shutterbug]

It might be good to mention here that you always press the bushing in from the back side (inside) of the plate. Just in case newbies are reading this :)

[Scottie-TX]

"Why is that, SHUT?", a newbie may ask.

[leeinv66]

"Why is that, SHUT?", a newbie may ask.

I'm not so new, but would ask the same question!

[doug sinclair]

Install from behind the plate, with the oil cup pointing DOWN, and with the newly broached hole over a bench block or a stump with a hole sufficiently large that you can tamp the bushing into place, FLUSH with the back side of the plate. This eliminates the need for messing up the inside finish of the plate with a file as you file off a bushing that stands proud. Also, saves time! On American clocks which usually have long pivots, the bushing should be left full length as it should reduce the wear rate since you end up with more bearing surface, as well. Use proper reamers in calibrated sizes with a bushing set in matching sizes. Eliminates a lot of time consuming "cut and fit" work, and the frequent peening to close an overly large hole.

[shutterbug]

And bushings pressed in from the front have a nasty tendency to pop out during reassembly :)

[hugha]

Thanks everyone for your great replies. Some really good ideas there and also a few nice reassurances that my present methods are reasonably sound.

I'll certainly be investing in some more reamers and bushings.

Cheers
Hugh

[DrSchlock]

If using broaches, I've also heard that you should broach the pivot hole from the outside and the inside of the plate so the pivot hole has a slight "hourglass" shape. Or is it better to do only one side?

[T.J. Kloss]

Hi all

I'm a bit late into the thread but, here is an example of peening plates to make bushings tight. It's a previous repair on an English clock movement that just went through my shop. Almost every pivot hole on the clock is bushed in this manner. This movement has 12 different repair dates scratched on the back plate. In all fairness to one of the previous repair person, the last picture shows a very nice and very old inlaid tooth repair on the snail wheel.

T.J. Kloss :cool:

[Veritas]

There is peening which is acceptable, and over peening in this case NOT acceptable, looks really bad and does nothing to hold the bushing in by pounding all over the plates.:confused::@:@

[harold bain]

Tom, that is one nasty looking plate:o.
As for bushing from the inside of the plate, the bushing reamers have a slight taper to them, so the bushing would fit tighter when pushed into the taper. Having the wider end of the taper on the outside would make them more likely to pop out.

[doug sinclair]

Commercially available reamers many of us use to open a hole for a new bushing, cut a cylindrical hole, typically 0.03 mm smaller than the bushings in a compatible assortment. I quit using tapered reamers (other than for fitting a pivot to a new bushing) about 25 years ago. Try them. You'll like them.

[harold bain]

Doug, do you mean the reamers made for the bushing machines, like Bergeon? Or do you mean hand reamers?

[Mike Phelan]

Hi all

I'm a bit late into the thread but, here is an example of peening plates to make bushings tight. It's a previous repair on an English clock movement that just went through my shop. Almost every pivot hole on the clock is bushed in this manner. This movement has 12 different repair dates scratched on the back plate. In all fairness to one of the previous repair person, the last picture shows a very nice and very old inlaid tooth repair on the snail wheel.

T.J. Kloss :cool:

Whoever did that, Tom, deserves to be hung and quartered!
The peening is just too big to put new pieces in. :(
BTW, is your third picture transposed L to R?

[doug sinclair]

Harold,

Since a typical reamer does not leave a cylindrical hole, I would be referring to reamers that are used in bushing machines such as the Bergeon. However, I understand that some use these reamers without using a bushing machine.

[R. Croswell]

If a manufactured bushing (or a hand made one with precisely the correct dimensions) is pressed into the correct size cylindrical (parallel sides) hole it should stay in place regardless of whether it is pressed in from the front or the back of the plate but………. The “oil sink” needs to end up on the outside of the plate. The commercially available bushings have a very slight relief at the oil sink end to help start the bushing into the hole. Attempting to press the bushing into the hole blunt end first (from the front) can shave off metal from the bushing or the sides of the hole ahead of the bushing resulting in a less secure fit. These bushings are designed to be pressed in from the backside of the plate.

Generally speaking, the ideal finished bushing should be as invisible as possible. That requires that the bushing be pressed in flush with both the front and back plate. Most repair people frown on leaving a bushing standing proud above the surface of the plate. If the bushing is “too long” and requires filing, I would rather risk marking the less visible inside of the plate. This is where a bushing machine has an advantage because there are cutters available that will quickly and neatly cut a bushing flush with the plate.

When the original plate is fairly thin and did not originally have an oil sink, installing a bushing with an oil sink will obviously reduce the bearing contact area. Considering that the so called oil sinks probably have little or nothing to do with improving lubrication, one could make an argument for pressing the bushing flush with the backside of the plate and cutting or filing away all or part of the oil sink end until it is flush with the plate. One could even make a point for pressing the bushing flush from the front (oil sink facing inward) and then cutting away the oil sink on the backside of the plate where it is less obvious. One caveat here is that if the hole in the plate has been opened with a tapered reamer, as is frequently the case with “hand bushing”, the bushing is best pressed from the backside of the plate so that it will have less tendency to “pop out”.

Bob C.

[itbme1987]

I have has 2 bushings want to pop out that i put in on a small gilbert banjo movement with the balance wheel because i had to put the bushing in from the outside. I used hand tools and the front plate of this movement had a ring of steel that was attached onto the posts for the dial and glass to go on and i couldnt see a way of removing this steel ring so i couldnt lay it on a flat surface and the center wheel was still attached so i had limited options, When i was using a smooth broach thats when they came out so i took a fresh bushing pounded it in and it stayed tight, then filed it down and left a little standing proud and layed my brass hammer on the bushing and took another hammer and hit the back of the brass one and i think some of the brass spreaded and helped secure the bushing better, then went on to broaching then pegging out and reassembling and they didnt come out. As Mr. Croswell said this one had a very thin plate so it was a bit difficult.

[Dave B]

I do not like to file bushings after they are installed. It is too easy to put scratches in the plates. I measure the plate thickness, and either select one that is the proper thickness from the commercially available ones, or face one off to fit. Before I owned a lathe, I used to face them off by chucking them up in a pistol drill, clamped to the workbench, and used a Dremel with a suitable end mill. It was painstaking, but functional. Of course, the easiest way to face them is by having a set of counterbores, but who can afford the cash outlay for the wide variety of sizes that would be required? Certainly not I.

[hugha]

After seeing the horrendous plate peening job posted by T.J. Kloss, though I'd better make it clear that any peening I do is applied to the bush only and not the movement plate.

Once again, thanks everyone for the interesting and helpful responses to this thread.

Cheers
Hugh