steel shim used as a thrust washer?

Greetings all:
I have my Triumph gearbox apart for a refresh and while going thru the vari=
ous tolerance checks,one of the thrust washers is too thin by 0.015 inch. =
This part retains the 1st gear axially on the trans shaft. This part is no=
longer available in any thickness - originally this part was available in =
4 thickness ranges.
formatting link
The existing thrust washer is hard=
ened. Since there is no rotation on this part (unless the mainshaft bearin=
g seizes and then I have much bigger issues). I am thinking of using a 0.01=
5 thk round steel shim as a spacer between the bearing inner and the existi=
ng thrust washer. This part would not be hardened (Rockwell B85).
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Does anyone see an issue wit=
h this? =20
The other alternative is to turn a thrust washer on the lathe out of some m=
ystery steel. Problem is that I have a difficult time parting off and keep=
ing the cut square. I do not have access to a surface grinder.
Reply to
aribert n
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tolerance checks,one of the thrust washers is too thin by 0.015 inch. This part retains the 1st gear axially on the trans shaft. This part is no longer available in any thickness - originally this part was available in 4 thickness ranges.
formatting link
The existing thrust washer is hardened. Since there is no rotation on this part (unless the mainshaft bearing seizes and then I have much bigger issues). I am thinking of using a 0.015 thk round steel shim as a spacer between the bearing inner and the existing thrust washer. This part would not be hardened (Rockwell B85).
formatting link
Does anyone see an issue with this?
mystery steel. Problem is that I have a difficult time parting off and keeping the cut square. I do not have access to a surface grinder.
It'll be fine sandwiched between the original shim and the bearing. The original is hard because it has to bear on the retaining ring.
Reply to
Ned Simmons
The other alternative is to turn a thrust washer on the lathe out of some mystery steel. Problem is that I have a difficult time parting off and keeping the cut square. I do not have access to a surface grinder.
How about turning a full-thickness replacement from the head of a grade 8 bolt?
jsw
Reply to
Jim Wilkins
tolerance checks,one of the thrust washers is too thin by 0.015 inch. This part retains the 1st gear axially on the trans shaft. This part is no longer available in any thickness - originally this part was available in 4 thickness ranges.
formatting link
The existing thrust washer is hardened. Since there is no rotation on this part (unless the mainshaft bearing seizes and then I have much bigger issues). I am thinking of using a 0.015 thk round steel shim as a spacer between the bearing inner and the existing thrust washer. This part would not be hardened (Rockwell B85).
formatting link
Does anyone see an issue with this?
mystery steel. Problem is that I have a difficult time parting off and keeping the cut square. I do not have access to a surface grinder.
I think that the first question is "how did the spacer get to be 0.015" too thin? Did it wear or was it originally assembles that way? If the latter then the next question is "how long has it been that way and did it shift all right ".
Cheers, John B.
Reply to
John B.
Possibly there probably was a second spacer, oftentimes these kind of things were intentionally designed with a loose fit and then the actual gap was measured during the assembly process; finally, the appropriate shim was selected and installed....
In fact, anyone that's rebuilding automatic transmissions is going to have on hand (or at least he SHOULD have ) certain kits containing parts that are commonly known as "selectables"...
--Basically, these are clutch plates that are a bit thicker (or thinner) than your stock plates...if you need an extra .005 then you pull out one that's say, .060 thick and replace it with a .065.
Then again, on the part pictured, it might not really be all that important--it's a helical gear and so depending on exactly where it is in the gear train, an extra .015 or so really may not be a big issue when it comes to the actual amount of force that is developed when it impacts against the snag ring as the throttle is suddenly let off.
Reply to
PrecisionmachinisT
As spares become No Longer Available, gearboxes are built up from several p= arts boxes. The excess axial play has been there for the last 8 years (20K= miles). I was not observant enough when I dismantled my worn but function= al trans and a parts box. The issue with this trans was a slow upshift fro= m 1-2 (1 sec pause during upshift) and major difficulty on both a 3-2 & 2-1= downshift. Over the past 5 years I found NOS 1st gear and 1-2 shift hub = along with a newly reproduced 2nd gear. Synchros back in the late 90s were= garbage -supposidly good quality now. All the other axial tolerance check= s are in spec on the low side.
I bought 0.015 thk round shim from McMasterCarr. I considered turning a th= rust spacer but my inability to part off square and to tolerance means that= I would end up filing & lapping the thrust washer to tolerance (but probab= ly not a uniform cross section). I really want a surface grinder or access= to one.
Reply to
aribert
boxes. The excess axial play has been there for the last 8 years (20K miles). I was not observant enough when I dismantled my worn but functional trans and a parts box. The issue with this trans was a slow upshift from 1-2 (1 sec pause during upshift) and major difficulty on both a 3-2 & 2-1 downshift. Over the past 5 years I found NOS 1st gear and 1-2 shift hub along with a newly reproduced 2nd gear. Synchros back in the late 90s were garbage -supposidly good quality now. All the other axial tolerance checks are in spec on the low side.
spacer but my inability to part off square and to tolerance means that I would end up filing & lapping the thrust washer to tolerance (but probably not a uniform cross section). I really want a surface grinder or access to one.
What..no machine shops in your area? Go in on a Tuesday morning with a box of donuts and ask if they could grind your spacer flat.
flattening out a spacer takes maybe 3 minutes on a surface grinder. Hell..stick it in an envelope and send it to me with 50 cents for postage back and Ill do it.
Gunner
Reply to
gunnerasch
a thrust spacer but my inability to part off square and to tolerance = means that I=20
probably not a uniform cross section). I really want a surface grinder = or access to one.
You'll probably be fine, even if it does eventually end up in pieces in = the bottom of the case...(which probably won't happen so long as it was = properly heat treated for use as a thrust washer)=20
But in the future, I would suggest using a pair of spacers that are = fairly close to one another in thickness rather than having one of them = be thin enough that it might easily tear or crack in use.
Reply to
PrecisionmachinisT
Material that thin doesn't stick to the mag chuck very well. I have a lot of trouble grinding 0.025" hacksaw blades. When the wheel grabs the work it launches it at ~60MPH. Also you can overheat and soften it.
Reply to
Jim Wilkins

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