Jumbo Giant Drive Coupling

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Model T Ford Forum: Forum 2012: Jumbo Giant Drive Coupling
Top of pagePrevious messageNext messageBottom of page Link to this message  By Nick Stanley on Sunday, April 08, 2012 - 05:47 pm:

Does anyone have a Jumbo Giant aux. transmission drive coupling they would sell? Just figured I would try before I make one. Thanks all.

-Nick


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Danuser on Sunday, April 08, 2012 - 07:45 pm:

I have a friend making some, but of coarse they are are not in a hurry


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Monday, April 09, 2012 - 01:45 am:

I need two. I plan on making them myself. That is a problem with the JG, Most of those couplers were lost.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Hatch on Monday, April 09, 2012 - 08:39 am:

Nick: Email me, I think I still have one. danielh462@centurytel.net Dan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, July 02, 2012 - 02:09 pm:

I've also found a Jumbo trans without the coupler parts. Does anybody have the dimensions for making them? Or any for sale?
Here are Dean Youder's pics of the parts from another thread:

jumbo coupler 1
Jumbo Yoder

Thanks for any leads :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Thursday, July 05, 2012 - 04:21 am:

Wayne S, you mentioned making coupler parts yourself back in april - do you have the measurements?

I would be very interested in the measurements of the parts in case I have to make them myself too.. (no other Jumbo's around here to measure from)

Is it possible to make the part thet fits in the T trans output shaft from an old T U-joint?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Tuesday, July 10, 2012 - 11:07 pm:

Sorry, I have been detained and away from the computer for a few days.
The two Jumbo Giants I have are for projects that I hope to begin working on in a year or two. So I have not spent any time figuring out the particulars to make those pieces. I did look it over a year or so ago, and I figured, with just a little finagle, I should be able to make a good coupler out of a marginal U-joint. It would not be exactly like the original, but until Dean's posting awhile back, I had never seen exactly what one looked like.
This is not the best idea. But I would cut the front square off the U-joint, leaving enough for a wide spread to braze a steel disc onto (for some attachments, brazing is stronger than welding). I would then cut a single plane slip-joint. The problem with this is that the transmission must be nearly perfectly aligned when installed. The advantage to this is that it is easier to make the coupler stronger. An important consideration when cobbling together a Joe Maggee fix.
Important! Do not forget to provide good spring pressure to push the single (or better yet, double) plane coupler back into the transmission's single plane coupler. A hole needs to be drilled in the end of the U-joint square, and an appropriate spring placed in it to push the coupler back tightly against the input to the Jumbo G. There is a correct name for those couplers, but I do not recall it off the top of my pointed little head.
It should be easy to figure the measurements. They all need to be referenced to and from the same point, dead center across the back of the fourth-main-ball-cap.
I may be able to draw something up in a few days. But I make no promises.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, August 13, 2012 - 06:16 pm:

Now I've bought the coupler parts, thanks to Andy Loso :-)
I made a couple of pencil scetches with measurements I took. Not sure about tolerances, but if you make them reasonably like mine I think it'll work - if the material and the heat treatment is good enough.. But this isn't 400 hp racing machines so many modern steels should work, I think?

Unfortunately the front half from a Ford U-joint can't be easily used - the u-joint doesn't have material where needed, if you want to use one you must make an adapter giving distance between the jumbo giant and the hogshead/oil pan - then it might be possible. Got to make the disc too, but it's more straight forward machining.

jumbo coupler

Jumbo disc

Sorry, you've got to turn your head at an angle to read the drawings :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, August 13, 2012 - 06:27 pm:

Did you find the fault? The coupler wouldn't be able to connect with the disc if you follow the measurement above - I didn't make the conversion from my caliper millimeters to inches right.. (0.533" should be 0.494")

So here's the updated scetch:
jumbo coupler 2


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