Bushing Washer for MK IIIs question

patrickiv · Post by **patrickiv** » Tue May 22, 2012 11:17 pm

Bullseye, what type of steel did you use for this bushing? I'm interested in turning my own.

Post by **Bullseye** » Wed May 23, 2012 6:40 am

I used some tool steel. A or W grade works fine for this application. I wanted to keep wear to a minimum.

R,
Bullseye

patrickiv · Post by **patrickiv** » Thu May 24, 2012 3:28 pm

Would stainless steel work for this application? If so, what grade would be required?

Post by **Bullseye** » Thu May 24, 2012 4:28 pm

I would not use stainless as it is prone to galling under the conditions you have here with the hammer pivot pin and the mainspring's tension.

R,
Bullseye

patrickiv · Post by **patrickiv** » Thu May 24, 2012 5:40 pm

Interesting...I'm not very educated in metallurgy, I just really hate rust(I know that stainless can rust too). I saw that VQ used to make MKII bushings in stainless, but they're sold out everywhere. I think I'll give Sam's bushing a try.

Post by **Bullseye** » Thu May 24, 2012 7:05 pm

High carbon steel, which is what tool steel is, is very strong and is not very prone to corrosion. Before the bushing would corrode, most of the rest of the pistol would be heavily encrusted in rust. You asked what I used and why, you have my answer.

R,
Bullseye

blue68f100 · Post by **blue68f100** » Fri May 25, 2012 9:02 am

The Clark MKII Bushing is over size so it fits the hammer snugly, comes with a matching pin for the MKIII (not 22/45). This eliminates one of the rotating surfaces and creep from the trigger. I've also used LocTite to secure the bushing to the hammer too. Another thing on the Clark is that it will limit hammer/sear engagement to around 0.020". Where a stock setup is around 0.025" if I recall.

There is very little load on the bushing. Making one out of stainless will work but most stainless are soft, 300 series. High carbon steel like 4130 is a good choice then cold blue the part to slow the rust process down. You will still need to keep some oil on the inside pin area.

Sam Lam has been making these bushing for years and does do custom on request. So if you want a snug fit measure you hammer hole and have him make one 0.001" over size and you will be set.

All work.....