DP70 Gate Intermittent Bushing

[Henry Atkinson]

One of our 70mm gates just had its brash bushing give up the ghost - edge rolled over, crack in the brass. Looking for replacements, and having trouble finding any dimensioned correctly. Measuring our good ones, I'm getting:
ID: 8mm +/- 0.03mm
OD: 13mm +/- 0.06mm
Depth: 10mm +/- 0.5mm

Anyone ever had to find replacements for these, and if so:
1) Do those dimensions sound right, and if so, where were you finding them? McMaster doesn't have anything with the correct ID/OD combo
2) Are these just normal brass, or are they oil-permeable? There's an oil fill port on the top of the intermittent shaft support on the gate, but seems to just fill a channel around the bushing in that piece of the casting.

[Mark Gulbrandsen]

I always used an oilite bushing and lapped it to fit the star wheel shaft properly, then the few drops of oil you put in that oil hole will actually keep the oilite bearing itself saturated. Contact, or better yet, take the old one to any large bearing supplier and let them measure it. There is a Motion Industries in Auburn that should be able to help, but if they can't, they should be able to refer you to someone that can.

Contact Motion Industries in Auburn at.... 508-229-2688. You will need an arbor press to remove it and then press the new one back in place. Possibly an appropriate lap and some lapping compound to size it correctly. Worst case, you may have to find a machine shop that can make you a bushing. I thought you had a spare machine there??? Isn't there an outboard bearing on it?

[Henry Atkinson]

I'll check with Motion Industries in Auburn, I appreciate the pointer. We do have a spare machine, but we purchased it as barebones as possible (just needed the driveshaft out of it at the time), so we didn't get any gate/swap kit with it. That being said, we do have a spare intermittent, so I can take measurements off of that to size a "correct" bushing as all of ours are most likely originals and very worn-out.

I do have a whole machine shop at my disposal, so worst case, I'll turn my own bushings, just trying to avoid doing that since all of our manual lathes have been replaced with CNCs, and I have to cut an amount of red tape to get time on them. I took the opportunity to press out all of the good bushings as the oil passage behind the one that failed was totally clogged, and we were three for four on completely clogged oil passages. Cleaned them all thoroughly and pressed the good bushings back in - I'm sure that had something to do with this one failing.

[Mark Gulbrandsen]

Well, in my instances none of them ran 70mm. Just 35mm, so the wear to that bushing was almost zip. Yes, I think you'd find the oil passageway clogged on just about every machine out there. Plus you could put a flashing neon sign up to remind people to put a few drops in that bushing, but they never do. That outer bearing is not all that important for 35mm. The main housing of the intermittent supports most of the star shaft. I gathered that it was there mainly for 70mm. Most European projectors do not have any outer support for that shaft. Shakeameccanica, Prevost, Bauer, etc, all had zero outer support. ALso, if you do make your own, be sure to lap the bore so there is oil clearance.

[John Eickhof]

Like Mark stated, it should a sintered (oil impregnated) brass/ nickel alloy bushing. you should be able to find them locally, you may have to cut to legth though, but a lathe will make that simple.