Film-Tech Forum ARCHIVE: Simplex 35 sound head SH7310 Drive Belt

This is topic Simplex 35 sound head SH7310 Drive Belt in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Nils Hoover (Member # 6636) on 07-29-2012, 04:43 PM:

Belt broke, apparently we don't have any spares. It is a simple thing... we just can't get a hold of the part.

It is the drive belt that connects the motor to the soundhead unit.

http://i.imgur.com/B8d69.jpg - belt connects to projector on (now) beltless gear.
http://i.imgur.com/XIyYE.jpg - belt connects to motor bottom left

Can't find the specs in any manuals online, it is 13inches long and half an inch wide with teeth.

Can some one tell me what exactly I need, and if I could a generic drive belt close to it, that I might get at a local store to hold me over? And if that is a bad idea, where I could buy it online.

Our normal film part/equipment distributors aren't open on sundays, will probably just get the right thing from them tomorrow (overnighted for the next day), but if there is any where close that sells the correct part, or something very close (unless that is a really bad idea), we would just drive there to get it so we don't lose another set of shows tomorrow.

Any help would be appreciated, thanks.

Posted by Tony Bandiera Jr (Member # 2365) on 07-29-2012, 04:59 PM:

Odds are it is a standard timing belt, the "generic" number would be 260XL050 (260 teeth .050 pitch) If you call a bearing shop or perhaps Grainger's they should have it as a stock item.

Posted by Gordon McLeod (Member # 33) on 07-29-2012, 05:07 PM:

There were several different belts used by strong depending on the motor
early ones were not metric pitch
take the remains of the belt to a bearing shop

Posted by Tony Bandiera Jr (Member # 2365) on 07-29-2012, 05:11 PM:

Gordon is correct, however by looking at the pics the pulleys are the square tooth type and again odds are it is the 260XL050 type in this case.

He is also correct that you should take the remains of the belt to the bearing shop to match it up.

Posted by Steve Guttag (Member # 268) on 07-29-2012, 07:29 PM:

VERY few SH7310 heads would have been converted to round tooth belts (we did it but it does not use the same spacer/shim set as late-model 5-star. Odds are, your P-7015 bearings and that sprocket shaft are going to be rather undercut once you pull all the stuff off. Note, the projector and soundhead belts are the same...do yourself a favor and change them both.

Tony is correct on its specs 260XL050. We probably have them in stock if you strike out locally. I say probably where, once upon a time, it would have been deep-stock due to the change in demand on such things...the same goes for the bearings and sprocket shaft.

Posted by Monte L Fullmer (Member # 2797) on 08-03-2012, 02:55 AM:

(best get all of that grease and oil up for that stuff loves to eat belts real bad...)

I've purchased these belts from McGuire Bearing for less than 8 bucks apiece. I've seen them at Grainger, but not know of the prices.

Oh, for the round tooth variety (for reference sakes):

HTD-670-5M (metric measurements).

These are a bit more spendy.

EDIT: wasn't the 7310, the early 5 star with the solid door, different snubbing action and built in the early 70's?

thx-Monte

Posted by Louis Bornwasser (Member # 3063) on 08-03-2012, 08:15 AM:

If you find these off-the-shelf you are very lucky. I still have many. When we went to a very large "drive" supplier, they had every belt except this one; they couldn't order it from stock either. Apparently the length is non standard. They had them made for me, but I had to take a large supply. Louis