bronze bushing

This relates to this musical instrument I'm planning to build...

There are buttons (approx 7/8 inch diam) attached to 1/8 inch brass rod shafts. I want the shafts to slide in bronze bushings. By the nature of the instrument, the player will often be pressing near the side of the button rather than in the middle. The bushing will probably need to be about 5/8 inch long.

What do you recommend for the bushings? I can buy 1/4 inch bronze rod from MSC and drill it out on the lathe. Or maybe a combination of drilling and reaming? I guess this will depend on the 1/8 inch brass rod I get, and how accurate it is. I can get brass rod from MSC, also I see that RC hobby suppliers carry brass rod in various small diameters.

Should I try to look into Oilite? This would probably be overkill, right?

All advice, suggestions, ideas, etc. will be much appreciated.


Reply to
Will Self
Loading thread data ...

Greetings Will, Don't use bronze bushings with brass rods. They will tend to stick to each other and will wear fast. Instead, use steel bushings. MSC sells drill bushings which are hardened and polished in the bore. Polished, hardened steel against brass is a pretty good combination. If the steel bushings won't work (corrosion from moisture?) then plastic bushings will also work real well. Nylon or delrin. Acetal plastics, of which delrin is one, absorb much less moisture than nylon and so won't swell in humid conditions. Here we go, 1/8 I.D. 1/4 O.D. acetal tube, 60" long, $3.03. MSC# 63384697. Don't know how close they hold the I.D., but it's cheap enough to buy and experiment. The O.D. would need to be supported. Maybe drilling holes in the instrument will work. You can also buy solid acetal rod and drill it yourself. You will need to use a slightly oversize drill because the plastic drills undersize.The hole size depends on how hot it gets when drilled, the type of drilling lubricant (water is fine), how sharp the drill is, etc.. Acetal can be turned and bored easily. I machine a lot of it and hold +/- .0003" tolerance with temperature contreolled conditions. Cheers, Eric R Snow, E T Precision Machine.

Reply to
Eric R Snow

The oil in the Oilite would probably attract and hold grit from the air speeding up the wear -- especially if these are serving to control air valves.

There is a Teflon impregnated Delrin (acetal) available in rod form which would make a very nice bushing in combination with a polished steel or brass rod. MSC carries it, though you may have to look through the descriptions to find it, as I don't remember the name. (I've got some downstairs, but it is too late, and I am about to go to bed.

Good Luck, DoN.

P.S. It sounds somewhat like a button accordion, just offhand.

Reply to
DoN. Nichols

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.