MTFCA Forum

When doing research on rebuilding my transmission, I read a reference to a home brew method to concentrically grind tripke gear pins. Does this sound familiar to anyone?

Might need some more details on your question, but if you are talking about removing the pins to resize, not a good idea for refit to fly wheel, if doing them on the fly wheel I haven't heard of that. Now if new pins, they need no more than polishing to a fine finish in a lathe or drill if they fit in the chuck, 1000 or 1200 paper will do just fine.

Most repro pins do not have the shoulder on them that Ford put there. The shoulder kepts the pin from coming out the gear side of flywheel.
Have not seen this happen but have heard of it.

My question is mostly out of curiosity. There was a discussion of triple gear pins ( on the transmission side) sometimes becoming slightly egg shaped due to the side load, and if I remember correctly, the process of 'concentric grinding' of the pins was mentioned in passing.... And it was a bit difficult for most amature mechanics either that, or 8 wondered if there was such a process, as I looked for the thread again for an hour, and couldn't find it again! Lol

I have not heard of the pins having 'keeper' shoulders. Maybe the figured they weren't needed with the tapered set in the flywheel.

For rotating parts, rounder is generally better...unless you wanted a cam in the first place Some of the noise generated could be from accumulated eccentricities of high rpm small parts.

If the point sought from that previous post was based on past comments made by me, it was said for the reason that there were two known suppliers at that time and one supplied 'rounder' then the other. Point of Observation for anyone who cared to know, that's all. Sorry if I confused.

As far as the 1/8" rim shoulder not being on repro pins that is generally true...probably based the idea that a lot of folks did not know a rim was an OEM feature and folks were having a habit of pressing pins out in the wrong direction and when they didn't come out of the flywheel just went to a larger press.

There is also anecdotal evidence that has been passed around that actual replacement pins from FORD may not have had a rim...but the same evidence also had a larger flywheel shank area diameter 0.683/0.682 as the 'AR' replacement version vs. 0.680/0.679 for new.

FWIW

I happen to have a NOS pin - I'll have to go measure it !

dhosh wrote: ↑

Mon Sep 07, 2020 12:08 am

My question is mostly out of curiosity. There was a discussion of triple gear pins ( on the transmission side) sometimes becoming slightly egg shaped due to the side load, and if I remember correctly, the process of 'concentric grinding' of the pins was mentioned in passing.... And it was a bit difficult for most amature mechanics either that, or 8 wondered if there was such a process, as I looked for the thread again for an hour, and couldn't find it again! Lol

I have not heard of the pins having 'keeper' shoulders. Maybe the figured they weren't needed with the tapered set in the flywheel.

Dennis,

Do you maybe mean "centerless grinding"?

Jerry...

I remembered reading concentric (sp)? .... But perhaps it means the same thing?

I had ordered new pins just in case.... But think mine will be fine.

George... Were you one of the 2 gentleman that did the blind testing of pins and bushings? Some treats back? Sounded like a LOT of work!

Here is link to one of many threads on pins..
look down to ,I think the Feb 7 post and you will see a picture of the Ford drawing of triple gear pin. You will see shoulder. Without this pin can come out gear side of flywheel.
I have seen that happen, but others have. Dan
viewtopic.php?t=1166

Interesting, Dan.... And how the magnets would (intentionally or not) ace as a safety to keep the pin from falling out the 'back side'.

Dennis,

Yes, the late Ralph Ricks talked me into the Idea of a blind forensic test of pins and bushes and he offered to supply all of the blind samples, I’d get my people at work to do inspection to the Mercedes protocol (we did all the rotors and caliper frames for MB at the time), I’d get the lab rats to use the mass spectrometer to analyze every sample for chemical content, Then slice n polish to look at grain structure under a scope so We could confirm heat treatment——or not....and...

I think I got every used set of pins and bushes his locals had pulled off in every tranny rebuild ever done there in Southern California. We then added new from every supplier in an attempt to see if all the present stuff were single supply or not and get inspection data to the 4th decimal place.

It all kept growing legs which wasn’t all that bad as we learned a lot at each fork in the road...I had what academics call a “stack pass” into the e-libraries of some pretty serious academic places and that caused some big diversions into Neverland while Ralph remained Chief Cheerleader. So we felt like Don Quixote’s beating the windmills. Ralph then was diagnosed then he passed and that knocked the wind out of my sails...and guaranteed that the samples and their tags would stay blind forever as he never gave me the source sheet.

After all that there were still a few imponderables ( Do enough research into this stuff you find the last pickle in the barrel can never be caught in all things Ford...lol)

Yes it is very interesting. The magnets holding the pins is why I always install one of Dan M’s rings on a flywheel that I remove the magnets off of for a customer. I have not ever seen seen a pin back out, have heard of them. I also only install pins with the shoulders now for same reason.

Ford Service Bulletin, Nov. 1924 describes the use of the 'AR' part suffix triple pin, as opposed to the factory pin which can't be reused if punched out as the hole in the flywheel is now enlarged slightly.