The Coolidge Chronicles #19: Part 3 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Rebuild

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Blog entry by darthford posted 01-16-2014 07:57 AM 2586 reads 0 times favorited 5 comments Add to Favorites Watch
« Part 18: Part 2 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Rebuild Part 19 of The Coolidge Chronicles series Part 20: Part 4 - 1952 Delta Multiplex 40-B 12"-14" Radial Arm Saw Rebuild »

In part 3 I finish up all the repairs, here we go…

This is a micro adjuster for the turret. On the Delta 40-B both the carriage and turret slide forward and back, the carriage on the carriage bearings and the turret on dovetail ways ground into the top arm. On many radial arm saws after 1952 the turret is fixed.

There’s a gear track up under the top arm this adjuster meshes with. The reason the shaft is ground so small left of the gear with that big chamfer is it has to reach over the dovetail way to get to the gear track which is up behind it.

So…I had a brain malfunction. Rather than fix the original adjuster and decided I should machine a whole new adjuster from scratch out of a big 3/4 inch grade 5 bolt. Well 2 broken C5 carbide bits later the bolt had defeated me, dang those things are hard. Hence I fixed the original adjuster below.

Here you see I machined the broken gear off with the lathe.

I found a new gear at McMaster Carr but it can’t go on this way due to having to clear the dovetail way in the top arm.

I turned it around.

I brazed the gear on with a torch then trimmed it leaving a hub of material for added strength.

Here’s the most mangled part on the saw, one of two eccentric cam bolts for the carriage. This thing was so mangled I had to force it out of the carriage with a hydraulic press. The hex socket was stripped out and the bolt was galled badly from someone over tightening a set screw. This part really should be thrown away but I decided to repair it temporarily for now so I can get the saw back in service.

Here I have machined down a socket head screw and plan to braze it on with a torch and brass brazing rod.

Here it is test fitted, the fit was fair not great.

Here it is finished, brazed on then turned on the lathe so the hex nut will fit. I had some brass wick up the threads a bit fortunately I had a die on hand to clean them up.

I decided to machine another brass bushing, this is for the front of the base where the crank handle is located to raise/lower the column. I’m using a 1” solid round of 360 alloy brass, it machines very nice dry no lubricants. I hogged out the hole with a couple drill bits and an end mill then bored it. Here I’m turning the OD.

Here’s the new one next to the old one.

Here it is installed in the cast iron base, again the casting was bored out of round so I had to rework it with a Dremel.

Finally I repainted the motor black.

In part 4 finally reassembly begins!!!

5 comments so far

View Handtooler's profile


1578 posts in 2159 days

#1 posted 01-16-2014 11:59 AM

My, my You must be a master machinist by education and career to do such nice work. No wonder you went for the big, heavy fine stuff for your recently updated shop. Thanks for the blog

-- Russell Pitner Hixson, TN 37343

View Kaleb the Swede's profile

Kaleb the Swede

1835 posts in 1996 days

#2 posted 01-16-2014 12:55 PM

Great work darthford. Once again very fun read. That radial arm saw is going to be one cool machine when done. I’ve never used one so I don’t know. But if given the chance with a machine like that I would.

-- Just trying to build something beautiful

View smitdog's profile


368 posts in 2132 days

#3 posted 01-16-2014 02:05 PM

Great read, and some great machining skills! Can’t wait to see the finished vintage RAS!

-- Jarrett - Mount Vernon, Ohio

View darthford's profile


608 posts in 1950 days

#4 posted 01-16-2014 03:23 PM

Thanks guys the next blog on this project is going to be loaded with fresh paint and shiny new parts going together stay tuned!

View chocolyle's profile


1 post in 1257 days

#5 posted 01-12-2015 04:26 AM

I am in the process of restoring a Red-Star 40-A, prior to Rockwell/Delta buying them out. Your finished unit looks great!

Would you have any interest in repairing another micro-adjuster for the turret? Mine has the same problem as yours. Please let me know if you could, and how much. I can send you out mine. I can not find a replacement anywhere.

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