There have been plenty of times where I have needed to finish a transmission and I have needed a shim that I did not have, or I needed a shim that was not available.

In these pictures I show a trick that I did using common DIN 988 shim that I ordered from mcmaster.com that allowed me to use a certain 5th gear as a 6th gear. There does not exist an off the shelf shim that is available for me to order that fits the dimensions that I needed. However, I was able to find some that had the correct ID, OD, but were a little bit too thick.

Using just my press, scrap pieces of wood, packing tape, sand paper, and a very smooth surface I was able to procure an appropriate sized shim fairly quickly. The particular project that I was working on required me to do something like this, however there have been times when this trick would have allowed me to finish a transmission and get it shipped out. Hopefully some of you may find this useful.


1. Shim that is too thick:



2. Place thick shim on block of wood in press



3. Place block of steel on top of wood + shim.



4. Press down and create shim sized indentation into scrap block of wood. This can probably be done using a vise.






5. Tape down sandpaper onto a smooth surface. You will not need this much. I was experimenting in this picture. You will most likely want to use sandpaper that is 180-400 grit.



6. You now have custom 'shim holders' that will hold the shim in place, thus allowing you to apply enough even pressure to sand this down quickly.



7. Now, just like Method Man in 'Gravel Pit'
https://www.youtube.com/watch?v=Of-lpfsBR8U#t=1m50s
'Back, back and forth and forth'
'Back, back and forth and forth'



8. Measure throughout the process until you have produced a shim that is in your desired thickness.

 

Update: You're absolutely going to want a higher quality sand paper. Otherwise you'll be spending most of your time removing worn sheets + spraying glass surface with rubbing alcohol to remove glue / adhesive residue from tape / scraping residue with razor, and then taping on a new sheet. I spent more time than I care to admit researching sandpaper options / brands. The conclusion that I reached was that the '3M Pro Grade Precision' sandpaper was the best option for me. I placed an order on line for a few 20-packs of the 9x11" sheets in various grits, but then a few weeks later I realized that home depot carries bulk packs (15 sheets) of this in every grit that I ordered, and for less.
https://www.homedepot.com/p/3M-Pro-G...P-15/205415971

I haven't used any of this yet for sanding down shims, but the sandpaper feels higher quality than what I got from Lowes.

Good luck.