The Coolidge Chronicles #23: Part 7 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Bearings MRC 202SFF 12

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Blog entry by darthford posted 01-21-2014 07:57 PM 3491 reads 0 times favorited 1 comment Add to Favorites Watch
« Part 22: Part 6 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Rebuild Part 23 of The Coolidge Chronicles series Part 24: Part 8 of 8 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Rebuild »

Part 7 is a special edition blog focusing specifically on the carriage bearings. It took some leg work to track down an alternative bearing so hopefully this will save someone else all that trouble.

The original 4 carriage bearings were wasted, someone had previously pried off the dust covers no doubt in an attempt to clean/grease them but my 10x loop showed the races were rusted out. The original bearing is a MRC 202SFF 12 and no longer available anywhere on planet earth. So began the search for an alternative.

Wolfe Machinery has a bearing A80970 that will work. This bearing is for DeWalt radial arm saws and is itself no longer manufactured so Wolfe Machinery had to have these bearings custom manufactured. The minimum order was 1,000 bearings and custom manufacturing doesn’t come cheap so you guessed it these bearings are a bit expensive at $35 each. I ordered 4 so they gave me a discount $30×4 – $120.

The A80970 outer race was slightly smaller and narrower than the original however this proved to be a non-issue. The OD was smaller by .015 but that was easily soaked up by adjusting the eccentric cam adjusting bolts. The race thickness is narrower by .039 not a small amount, the A80970 seems to ride a bit deeper on the ways (1/4 precision ground hardened steel rods) but this doesn’t seem to be an issue it tracks smoothly. I have included some close up pictures to illustrate.

A80970 / MRC 202SFF 12 (original bearing)

ID .590 / .590
Inner race thickness .432 / .432
OD 1.575 / 1.590
Outer race thickness .432 / .471

1 comment so far

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7741 posts in 2574 days

#1 posted 01-21-2014 09:10 PM

Lookin’ good. Should be a sweet RAS when you’re done!

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