Triple gear pins pressed into flywheel

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
Arnie
Posts: 17
Joined: Mon Jan 07, 2019 11:32 am
First Name: Arnie
Last Name: Johansen
Location: USA

Triple gear pins pressed into flywheel

Post by Arnie » Fri May 22, 2020 11:49 pm

MTFCA transmission booklet on page 16, Figure 13, states "Standard triple gear pin diameters are as follows: bushing segment is .675, press fit segment, .680, tapered head .697-.689.
In that same booklet in the paragraph titled Triple Gear Pins, it states: "The magnets directly behind each pin must be remove in order to properly remove the triple gear pins as the pin are tapered with the large end to the magnet side. The taper is only about 1/8 inch long and measures about .687, so if you push it the wrong way you're forcing a .687 through a .680 hole.

My questions are:
A. Do the holes in the flywheel have any taper? If so, how long is the taper and the angle of the taper and at which end?

B. According to the above the triple gear pins have a taper but it seems to be at the end. Would the taper conflict with the straight press fit segment in the flywheel. Or is the taper act like a shoulder and limit the travel of the pin pressing. I do not understand if there is taper on the pin but not taper in the hole in the flywheel hole how does it properly mate? Would not a pin with a shoulder and a counter bore in the flywheel hole (larger than the shoulder diameter of the pin) eliminate the conflict of straight bore and taper bore of the triple gear pin when pressed together?

C. Is there a taper portion of the hole and press fit length in the same hole? I would think this would be a conflict as two elements are fighting one another ( a straight press fit on part of the pin and then a taper on another part of the pin).

Please explain!
Arnie


Dan McEachern
Posts: 330
Joined: Sun Jan 06, 2019 11:08 am
First Name: DAN
Last Name: MCEACHERN
Location: ALAMEDA,CA,USA

Re: Triple gear pins pressed into flywheel

Post by Dan McEachern » Sat May 23, 2020 10:13 am

The pins are not tapered. The bore is not tapered. The book is correct in that the pins must be pushed out toward the magnet side of the flywheel.
There is no counterbore in the flywheel to accommodate the slight shoulder on the end of the pin. The pin gets driven in or pressed in until the shoulder begins to embed itself in the flywheel material. Look at the bore in the flywheel after you remove the old pin and you can see the deformation from the pin shoulder.


Topic author
Arnie
Posts: 17
Joined: Mon Jan 07, 2019 11:32 am
First Name: Arnie
Last Name: Johansen
Location: USA

Re: Triple gear pins pressed into flywheel

Post by Arnie » Sat May 23, 2020 2:07 pm

Further research seems to indicate that the pins were not tapered. Perhaps the MTFCA transmission booklet information needs to be revisited!


Arnie


OilyBill
Posts: 142
Joined: Sat Apr 25, 2020 3:51 pm
First Name: William
Last Name: May
Location: Tucson, Arizona

Re: Triple gear pins pressed into flywheel

Post by OilyBill » Sun May 24, 2020 12:41 pm

it might also depend on the year of production. Hard to tell when they started doing something, or stopped doing it. Someone posted on here, and they had actual documentation that they started doing something on July 6th, and then ceased doing it on August 8th, the same year. So there are just a few thousand "T"s with that particular feature. (Nothing to do with these pins, just an example of how often things could change in "T" production.)


Ron Patterson
Posts: 131
Joined: Sun Jan 06, 2019 12:32 pm
First Name: Ronald
Last Name: Patterson
Location: Nicholasville, KY

Re: Triple gear pins pressed into flywheel

Post by Ron Patterson » Sun May 24, 2020 2:08 pm

That information can be found on the ROC (Record of Change) Cards for the flywheel (factory #T-701) and triple gear pins (factory #T-715) and associated Ford drawings depicting each change.

Post Reply Previous topicNext topic