I have my transmission stripped and the shaft has a run out of 0.5mm
It looks simple enough to have a new one machined up, but since mine is 100 years old, I am not sure I can trust the current dimensions.
Does anyone has these available?
2nd Question: I do have a spare 1927 Model T engine and transmission. Will the transmission shaft from the 27 fit in the 13?
Same question for the reverse drum on the 13 which is cracked... Can I grab the one out of the 27 and will it fit?
Do you read 0.5mm run out if you hold it in the flywheel end and measure at the end of the thin shaft? In that case maybe you can true it up in the lathe by holding the thin shaft and shaving off a little on both sides of the flywheel end, just enough to true it up?
If the transmission shaft in the '27 spare engine is in better shape, you can use that one - they should be the same except the '13 shaft is a great historical piece, marked with the date of assembly for your trans
New transmission shafts are available from the vendors too: http://www.modeltford.com/item/3331.aspx
The reverse drum should be the same in the '27 - but they were all prone to cracking, so there's about a 50% risk your spare is cracked too Good used ones are still possible to find in the US with some searching - and repros: http://www.modeltford.com/item/3301.aspx
Another part you should check out in the '27 engine is the crankshaft. Old DB cranks has about the worst reputation among all T cranks while '27 cranks were the least bad, especially if it's marked "EE". It has to be magnafluxed for cracks before use like every "T" crank - no Model T crank can be expected to last forever.
I checked the run out holding the thin end. The flanged end was 0.5mm out.
I cleaned up the shaft with emery paper and then centered the flange end to clean up the face a bit.
Your'e right about the date stamp, mine is stamped with the 1913 date...
Anyway, going to have a guy have a look at making me one, and if he can do it for a good price, I will go that way.
I'm stripping the 27 tomorrow night to see what I've got...
Are you sure about the shaft of the 27 fitting? It has the wide brake drum.
The transmission shaft from the vendors is advertised as for 1909-27, so I'm sure the shaft will fit. 0.5mm at the flywheel flange would be a bit much to shave off - might take the date too.. ;)
Most of the transmission was the same except for the brake drum and the driven plate. I've read about some specifics about the clutch plates in transmissions up until about 1915, I think you need to have a thicker clutch plate in the bottom. The distance washers were also different, usually three in newer transmissions, but if what you've got is useable, then there would be no problem.
You should check the '13 triple gears for loose rivets. If loose, the one piece triple gears in the '27 trans may work better for you, all depending on wear.
You should really buy a manual "The Model T Transmission" from the club, it's worth much more than the $12 price http://modeltstore.myshopify.com/products/service-manuals
Here are a couple of threads on cracks in the webs of reverse drums: http://www.mtfca.com/discus/messages/257047/309504.html?1346694269
If you are going to have a new shaft machined, maybe you can have it a little bit oversize so you won't have to change the bushing of the brake drum shaft and clutch plate shaft, just ream them to adjust clearance.
You also have to verify if the flat end of crankshaft is not out of round and then verify the crankshaft bolted with flywheel and transmission shaft. Some errors can compensate or cumulate.
Morning Roger, Philippe
I'm having a guy give me quote on making up a new shaft for me, and if he has a decent enough price I will get him to do it, otherwise I will go another direction.
Do either of you have, or know where I can find, the dimensions of an original shaft?
In this thread Jim Weir measured his shaft to 0.9966": http://www.mtfca.com/cgi-bin/discus/show.cgi?tpc=257047&post=401419
So if you make it 1" maybe you don't have to change the bushings in the brake drum like Philippe says
Another important function of that diameter is where the clutch hub is pressed on. Sometimes the hub is enlarged, but the diameter of the hole in the hub has to be checked for normal press fit without excessive force. At the end of the shaft it should fit into the driven plate bushing, there you can also check the dimension of the bushing and make the shaft accordingly.
The big radius in the flange end is important to withstand metal fatigue.
The repro guys in the US first forge the end to get a thick end to machine the flange from, thus they don't need to start with a large expensive piece of metal.
For me, the hardest part in machining a transmission shaft would be to get the dovel pin holes in the right position - but then I'm not a machinist. Good luck
Thank you Roger.
I just dropped the part off for the quote. It is not hardened material. I asked for a quote in similar material and perhaps something harder.
Thank you for the dimensions, I appreciate it. I will let you know what the costs are for interest sake.
Personally I would not get a new one machined. Would the steel be the same as Ford used? Would it have the ability to flex in service without becoming fatigued?
Neither am I a fan of making the diameter greater to save worn out bushings. The hole in the disc drum rarely wears enough to allow a greater diameter shaft to be inserted.
Good used shafts are both plentiful and cheap. Why take a chance with something else?
I agree, Richard, but Justin's reality in South Africa may be different from ours with scarcity of used parts and expensive import costs while maybe his preferred machine shop is cheap?
Lang's listing gives a clue on how they're made: "Made of 4140 and heat treated to 305 -320 brinell"
..But hopefully the parts from the spare engine will work
Roger is correct. I am slowly getting to know all the guys with spares, and I might/might not find one that isn't bent etc.
You are correct about the strength and flexibility. It is a soft metal, something similar to En3 and the machinist is going to use a similar metal.
Now the New shafts I saw are forged or of the 4140 which I am not familiar with. You have to think Henry's engineers had a reason for specifying a soft metal... flexibility etc
Why go for anything tougher, you might break something else!? I don't know, but I'm going to go with the machinists recommendations and try to get a similar metal.
By the way, not a bad cost at all... Glad I did the exercise, and after testing it, we will know if it really was.
Best of all, My transmission should be dead on. I'm going to have him check some of the other shafts as well...
Cheers and thanks again,
4140 is a super common steel alloy in the U.S. The steel you're thinking of using, En3, is a European standard. It shouldn't be too difficult to cross reference the 4140 to a Euro standard.
The all knowing internet tells us that 4140 coverts to;
42CrMoS4 - Alloy special steel
42CrMo4 - Alloy special steel
I just measured a few transmission shafts in the garage. A couple I'm planning to use and a couple of bad ones. Seems like Jim Weir's shaft may have been worn, my good shafts were 25.36 mm or 0.9984". The flywheel flange was just under 4" (3.997") in diameter or 101.52 mm. Thickness 7.97mm or 0.3138".
The smaller diameter at the end of the shaft for the bushing in the driven plate was 23.75 mm or 0.935".
Thanks Roger and Jerry!
Yes I love the all knowing internet too! Still I think my late grandfather could have forgotten more than I will ever know.
To that I say "challenge accepted"
Roger, that is what I needed, thank you! PM me if you need any,
The machinist recommends EN8 which is:
EN8 is a very popular grade of through-hardening medium carbon steel, which is readily machinable in any condition. (Refer to our machinability guide). EN8 is suitable for the manufacture of parts such as general-purpose axles and shafts, gears, bolts and studs. It can be further surface-hardened typically to 50-55 HRC by induction processes, producing components with enhanced wear resistance. For such applications the use of EN8D (080A42) is advisable. It is also available in a free-machining version, EN8M (212A42)
The hardness is 201-255 Brinnell
4140 is equivalent to EN19A and is ideally suited for this application..
I learnt something today...
The machinist says that without testing the Rockwell strength of my original shaft he would Guess it to be EN8...
So my question is: do I get it tested and if EN8 is close, go with that? Or EN19A ~ 4140 which is much higher tensile..?