Need Advice: How should I weld this cracked clutch plate?

[Tony Thompson]

I am restoring a Twin City 27-44 with a "double" Twin Disc clutch in it.
One of the two center cast iron clutch drive plates has a crack from it's center out through one drive pin hole to other edge. I have highlighted the crack with a black marker in the photo so you folks can see it better.
I plan to have all the plates milled of to ensure a smooth operating clutch, but I would like advise on what would be the best method to weld this crack because replacments are not known to be available.
After prep, and preheat, I can braze it, spray weld with nickel, or arc it with 99% nickel rod.
What would you folks do?

[J.B. Castagnos]

If I were doing it I would make a new plate. If you weld it chances are it will warp, need machining, will probably have to be ground due to hardening of the welded area. Clutches are usually sensitive to total thickness, machining a lot will mean having to re set the pressure plate.

[Andrew Mackey]

Although expensive, I would have the disc re-cast. Brazing/welding will surely cause warpage and distortion Trying to machine a Ni rod repair on a flat surface such as a clutch disc face, can cause problems as well Besides all that, when you are done, you may end up with even more stress fractures, due to the heating and cooling of the disc itself. If casting is out, replacement with another - used disc would be a better option.
Andrew

[NAMPeters]

Personally I would look for a chunk of ductile iron large enough to machine out a new part. That way you would get a nice part without having to deal with the stresses ansd strains reulting from casting or welding etc.

[K D Redd]

Find a water jet and have a new one built. A local company has one which can make spur gears. If a water jet can make spur gears a clutch disc should not be a problem. The one this company has can use a scanner to use the old one for the need dimensions.

Kent

[Elden DuRand]

Tony:

If the disk is 12 inches or less in diameter, you can buy either grey or ductile cast iron rod by the linear inch. Look at MCMASTER.COM and search for "Iron Rods".

From there, it's only a matter of removing all the metal that is hiding the disc.

Take care - Elden
http://www.oldengine.org/members/durand

[OTTO-Sawyer]

I'd have to agree with what others have already said, don't even try to weld it.

As long as it's only cracked in one area you have an excellent pattern to either have one cast or have one machined either from ductile Iron or from steel plate. If you find some steel plate the right thickness that is smooth & flat you may not even have to surface it after cutting out the disc and drilling the holes...

[1baker016]

I say go for it! Only because you won't be out much if things don't work out. I would take very exact dimensions of them first though so you could have others made if this does not work. If I remember the pre-heat temp for cast iron is 400 to 600 deg. F for SMAW and 1100 to 1200 deg. F for oxyfuel gas welding. Maintain pre-heat temps untill welding is completed. Use AC or DCEP (direct current electrode positive) I would V groove the crack and weld to 100% penetration. Then let them cool slowly.

[1baker016]

Another cheep way to do this is to buy a pipe blind flange large enough to make your disk. I would say a 14" 150 pound class blind flange would work. then just have it machined to spec. You can buy them at any pipe supply company and they are common stock. The 150# class should be thick enough if not go to a 250# class Just make sure the 14" is big enough have them pull one out for you and check the flange against your clutch.