Film-Tech Forum ARCHIVE: Repairing Jackshaft Christie P35c Shutter Gearbox

This is topic Repairing Jackshaft Christie P35c Shutter Gearbox in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jeremy Weigel (Member # 4208) on 09-14-2008, 05:10 PM:

For those that do machining, is it possible to fill in a groove cut into the outer end of the jackshaft on a P35c shutter gearbox? The groove in caused by the shaft slipping in the outer support bearing over time. I already checked with Christie on getting a replacement jackshaft but they don't carry this part any longer.

Posted by Mark Gulbrandsen (Member # 72) on 09-14-2008, 07:12 PM:

Actually that must be a really old jackshaft. Most of the JS's I've seen and repaired have an expandable spring steel thingy on the shaft at each end that causes the shaft to self center in the bearing bore. You sure you're not missing one of these springy things? The shutter driver has these too. If your shaft is really torn up replaccement is the only sure route... I don't think that shaft is all that expensive.

Mark

Posted by Tony Bandiera Jr (Member # 2365) on 09-15-2008, 07:19 PM:

If you pulled the old jackshaft and took it to any competent machinist, they could probably make another for you at a reasonable cost. Have them make a few spares too as it is the setup for the first one that costs the most money.. [Smile]

Posted by Jeremy Weigel (Member # 4208) on 09-15-2008, 11:20 PM:

Hey Mark,

The shaft I have is the one pictured on page 85 of the P35c manual in the manuals section. Its part #38.

Hey Tony,

I'll be checking into that as well.

Posted by Mark Gulbrandsen (Member # 72) on 09-16-2008, 06:28 PM:

Hi Jeremy,

Was not in the shop today... was out setting up a demo M Christie projector. I still think the spring equalizer on that end of the shaft is mmissing... I don't think the whole P-35 jackshaft assy. is all that expsnsive... the new ones are much nicer too.

Mark

Posted by Randy Bowden (Member # 587) on 09-17-2008, 12:05 PM:

Based on your initial post description here and your reference to the P35C projector. I would guess that what you have is not really a jackshaft at all, but the shutter gearbox assy? It's quite common for the main drive shaft to wear a groove on the outer end as you mentioned. There really is nothing you can do about fixing it other than replacing the entire assy'or having someone fab up a replacement. Christie does not sell the parts for these, only the complete assy. If you do have an actual jackshaft, as used the current production GPS machine, I would highly recommend you just replace the entire assy. The new version has larger bearings, and should last a long time.

Posted by David Zylstra (Member # 4230) on 09-17-2008, 12:20 PM:

I concur with both Mark and Randy - if the budget allows replace the entire assembly. I was recently faced with the decision to rebuild an old assembly or replace it with the new version - cost of all the replacement parts needed (from Christie) totalled out slightly less than replacing the entire assembly. After receiving the new assembly it was obviously a good choice since it was definitely an improvement over the old one (larger bearings); if I had opted for chasing down replacement parts locally I definitely would have spent more in time and gas (or shipping) than any savings over the full replacement.

Posted by Jeremy Weigel (Member # 4208) on 09-17-2008, 06:29 PM:

Hey Randy,

You are correct that it is the shutter gear box assembly. I got the "jackshaft" term from the exploded parts description in that P35c manual. I will probably just go ahead replace the gear box with their new version.

Posted by Mark Gulbrandsen (Member # 72) on 09-17-2008, 09:25 PM:

Jeremy,
Even the new shutter gearbox has been improved quite a bit. It's going to be the cheaper route to go... making a shaft is impractical unless you can find a home machinist with nothing to do...

Mark

Posted by Jeremy Weigel (Member # 4208) on 09-17-2008, 11:55 PM:

Yeah, I'll be giving Jim Graten a call tomorrow for the part#(s) to replace these worn gear boxes and hopefully I'll remember to ask about that alignment tool.

Posted by Jeremy Weigel (Member # 4208) on 09-18-2008, 06:46 PM:

OK, I'm a little confused. I spoke with Jim Graton and he said there is no replacement in any form (rebuild or upgrade) for these shutter gear boxes (P35c) available any longer. He suggested trying to find someone who rebuilds them. He did provide the name of a company in Florida to try, but he wasn't sure if this is an item that even they rebuild.

Posted by David Graham Rose (Member # 1450) on 09-19-2008, 01:00 PM:

Greetings

Far easier to remove the offending Christie projector, with all it's weaknesses, anmd install a Kinoton surely?

David

Posted by Mark Gulbrandsen (Member # 72) on 09-19-2008, 02:21 PM:

Ok, Now it's clear... you have the shutter gearbox... not the shutter driver assembly, two very different parts. I am pretty sure that Christie still has brand new gearboxes available for the 35C... I do know they are expensive though!!! I have a couple of good used ones in pulled projectors if that'd help....? I can't vouch for the condition of them except that they go round and round. Call me if you want one.

Mark @ CLACO
801-355-1250

Posted by Jeremy Weigel (Member # 4208) on 09-20-2008, 12:11 AM:

Hey Mark,

Well it turns out that our off-duty security officer has a friend that is a machinist, so he's going to see if he can fabricate the shaft.

Posted by Jeremy Weigel (Member # 4208) on 09-28-2008, 04:10 PM:

Randy or Mark,

Do you know the rotational speed of both shafts? I'm looking to replace both seals and need to be sure that I get replacements that are rated appropriately. Or if you have a preferred replacement that you would recommend.

Posted by Mark Gulbrandsen (Member # 72) on 09-28-2008, 10:19 PM:

All double blade shutters turn at 1440 rpm. I believe the input shaft is half that but to be honest I'd have to look at the gears to really tell. Perhaps Randy could confirm or correct this.

Mark

Posted by Randy Bowden (Member # 587) on 09-30-2008, 11:02 AM:

There are too many variations in these gearboxes to be able to tell you what bearings and seals you would need for the rebuild, you won't really know until you take it all apart. I would not give up on the idea of getting a new gearbox from Christie, I have had no trouble getting them, unless they stopped selling them more recently. Right now my vote would be for trying out one of the used ones that Mark has to offer. At the very least you may need to crack open the used one and add fresh grease.

Mark, you are right, for every one rotation of the drive shaft you get 2 full rotations of the shutter shaft.

[ 09-30-2008, 01:16 PM: Message edited by: Randy Bowden ]

Posted by Jeremy Weigel (Member # 4208) on 09-30-2008, 01:42 PM:

Hey Randy,

I had the shaft repaired. The gentleman "sleeved" the groove. I'm taking the unit to a bearing shop to have seals measured and ordered.

According to Jim Graton, Christie no longer sells (new or used) and no longer does repair/exchange on these shutter gear boxes. He said the company they used to make/repair them went out of business and given the extemely low demand Christie has opted to not seek another option.