Brass or Bronze

[ncollar]

I need a few bushings and thought I would just turn them. My question is brass or bronze? Which would be best to use?
Nelson

 

[shutterbug]

It's a huge subject, Nelson, and open to many opinions. Brass is original. Bronze is better for long term coefficiency. Use what you have, basically. Either way, you'll have a better operating clock.

 

[eskmill]

It all depends on a variety of factors including availability of the bronze alloy selected for the pivot hardness and thrust load of the bearing.

For example the second wheel pivot holes in post WWII movements have a high thrust load. It took ten years for Hermle and other German makers to learn why their 2nd wheel plated pivots fail turning the "highly efficient" movements into un-repairable scrap.

On these bronze is required. Of course the pivot must be mirror finished and glass hard else the job won't last.

 

[Willie X]

IMOE, bronze will last longer 'IF' you keep it oiled. If/when the oil goes away, the bronze will roughen and wear away the pivot faster than brass will. There are many pros and cons but for me there is a slight edge toward using the brass, so I do.
Willie X

 

[R&A]

You may find that broaching brass is much easier than broaching bronze. I try to use bronze on the Hermle and Kieninger movements. On the second wheel of each train and the gathering pallet pivot and the third wheel on the chime train. These are the wheels in which you will find the most wear. Always use a smoothing broach after broaching.

 

[MARK A. BUTTERWORTH]

IMOE, bronze will last longer 'IF' you keep it oiled. If/when the oil goes away, the bronze will roughen and wear away the pivot faster than brass will. There are many pros and cons but for me there is a slight edge toward using the brass, so I do.
Willie X

Right. In addition, the most important variable is the condition of the pivot, the material and how well it is polished. Hermle has experienced catastrophic wear on some of the bronze bushings when the pivots were not properly polished.

 

[R. Croswell]

In deed a huge subject. To complicate matters, there are many different brass alloys and bronze alloys. Generally, a safe choice is to use commercial brass or bronze bushings which are made (we presume) from a brass or bronze alloy suitable for pivot hole bushings. Hard to tell just what that piece of brass laying around the shop really is. As for the choice between brass and bronze, the safe area is if the original was brass then bush with brass, if the original was bronze (or the maker specifies bronze) bush with bronze. Using different than original material in an attempt to "improve" on the original design leaves one out on a limb by one's self.

RC

 

[brutusamiga]

EVERY time I order bushings from the clock supply house bronze is out of stock and I need to settle for brass.

 

[R. Croswell]

EVERY time I order bushings from the clock supply house bronze is out of stock and I need to settle for brass.

............so should one assume that bronze is so much in demand that the supplier can't keep it in stock, or that there is so little call for it that it is not practical for the supplier keep it in stock?

RC

 

[shutterbug]

I think it's being discontinued by some suppliers, and hopefully that will increase business for others enough to keep supplying it. I use it when I can.

 

[MARK A. BUTTERWORTH]

............so should one assume that bronze is so much in demand that the supplier can't keep it in stock, or that there is so little call for it that it is not practical for the supplier keep it in stock?

RC

There are several issues but excess demand is not one of them. One issue is getting the raw material from the mill. Brass is in wide usage and easy to get. Bronze is not and there is a long lead time and the hard bronze that folks want is very expensive. Those the principal reasons we decided against making bushings from bronze. Also, double manufacture everything in both brass and bronze are a great capital expense. There are only two places that actually manufacture in bronze to my knowledge and I found both of them to be highly unreliable in supplying us, so we discontinued those lines. We still do have quite a bit of the Swiss made Bergeon in bronze if anyone is interested that we are liquidating. In addition, my personal feeling has always been that bronze was no better than brass, although I do like to be able to sell the customer what he/she wants. Finally, the demand for bushings is down considerably. We make them in runs of 50,000 at a time, so it is quite a commitment. We are very complete in the brass line in both the KWM and Bergeon sizes. I hope this helps.

 

[ncollar]

To start with I thank everyone for all the wonderful explanations and some of their reasoning. I am just starting and as everyone at one time or the other, finances are not the best. Not saying I'm going to use something that will not work. I like to buy raw stock and turn a lot of my stuff. The cost a bar stock is not that bad so I like to have it on hand and if it is a little large, well I can still see the part in it. What I had in mind was 932 Bearing Bronze, 4 foot runs less than $5.00 plus shipping and I'm sure that will be a ten dollar bill. Still less than manufactures bearings. Thanks for all the ideas and especially the reasoning.
Nelson

 

[ncollar]

I have read almost all the post concerning the brass verse bronze and I come to a conclusion it is more a service thing. Both materials are very good but when they become dry, bronze can and will do more damage than brass. The real problem is just like a car- service, service and service. If you do not check the oil in a car it will do the very same thing as the clocks do. The big comment I've read is the ones being worked on are mostly around a hundred years, just how many times have they been serviced? I am kind of lead to offer a 3 or 4 year check up mainly for oiling more than anything. That might make a world of difference in how long the bushing would wear without going egg shaped.
Just my thoughts and I know we do not live in a perfect world.
Many happy tick-tocks
Nelson