ROCKWELL 21-122 milling machine REBUILD

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wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

When I went to install the motor mount I realized that the wires coming out of the hole in the back of
the column were going to be in the way of the motor mount.
After thinking about it for a bit, the only option was to put a couple holes out the side of the column.(pic 1)
pic no.2 The motor mount/motor are on and set up.
Next hook up the wiring/put oil in the spindle & gearbox and give it a test spin.
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wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
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Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

Well I got a bit of bad news on Thurs.
The powder coating won't get done till after the new year.
The main customer that uses Gray switched parts for some
needing a different colour.
So I went and pick up some parts to do the masking to
a more precise level to minimize cleanup after for fit
and tolerance. Some will have to get sand blasted and
then I can mask.
But more specifically I picked up the the end of table
bracket/power feed mount.
I just finished turning the leadscrew making spacers
fitting/fine tuning. You can see all the pcs/spacers
involved in the pics.
The best part is that I didn't have to add any length to the
end of the leadscrew shaft(pin or adapt a lengthening stub)
I still have 15.2" of length travel by using a custom made end of
table bracket that is only 1 inch thick and designed it to directly
mate with the power feed unit. And I didn't have to lose the
dial at the power feed end. On the bronze gear I turned off
some thickness on the outboard side and inserted a nylon
plate designed to keep chips out of the gear.
All thats left to do Is slot the thinwall spacer that adapts
the bronze gear to the leadscrew(to allow the shaft to gear key)
and put a keyway in the leadscrew. I'll have to go to a friend's and
use his mill to do that.
Attachments
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Last edited by rmac on Sat Dec 10, 2022 5:59 pm, edited 1 time in total.
Reason: Photo Orientation
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

Next while I'm killing time, I'll finish the motor pulley
for the vertical head. Quite a long time ago I made a
2 pc assembly machined of 1045 for 5 of the 6 speeds.
The assembly has a flange that center the 2 halves and
is bolted together. Then bored and broached.
I need to machine all the pulley Vees and 2 set screws.
Also I need to make the 6th speed pulley It will have
a short stub that will fit into the end of the main pulley and
drive off the keyway and be locked in place with a setscrew.
Because this pulley is made of solid steel as opposed to the
stock cast iron original(which was hollowed out) It will not
be as fragile as the cast one but also weighs probably double in
weight. When its finished I'll post the weight.
The weight will be a plus in use as centrifugal weight.
But will also strain the setscrew, so I bored and tapped the end
of the motor shaft for a bolt to take that load off the setscrew.
Attachments
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Harold_V
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Re: ROCKWELL 21-122 milling machine REBUILD

Post by Harold_V »

Slotting the screw may prove to be a bit of an issue. Not suggesting it won't machine ok, just that it has the potential to create a problem for you. You're likely to experience stress relief (from milling the slot), relaxing the screw. That would result in a crooked screw. If it occurs, you can expect the slot side to become the crown of the distortion. I'd appreciate hearing the results.

Use a sharp cutter to limit the amount of burring that will result from the cut. It's not going to be easy to debur the thread.

H

Edited to add a comment. The mill looks really nice!
Wise people talk because they have something to say. Fools talk because they have to say something.
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

The leadscrew will not be slotted/keywayed anywhere near the threads.
The slot goes in the shaft outboard of the bearing housings.
Near the key for the handwheels/dials.
For the bronze gear of the powerfeed.
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Harold_V
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Re: ROCKWELL 21-122 milling machine REBUILD

Post by Harold_V »

Ahhh! That makes sense. Don't know what I was thinking! :?

There's still a chance of change in the shaft. Don't assume it hasn't bowed a little.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

I've been sick the last few days, but finally got the pulleys done.
The original 5 step pc plus the extra 6 th speed weighed about
18-1/3 lbs and after the Vees were machined down to just under 15 lbs.
The front cast pulley in comparison weighs 7-5/8 lbs. w/o the brake
assy. From the Rockwell parts drawings it looks like the original cast
rear pulley is similarley hollowed out or similar weight.
So this pulley while basically replacing the missing rear pulley is also
a lot less fragile than the sock cast pulley and at almost double the weight
has a lot more flywheel effect.
So all thats left to do here is machine a keyway in the stub of the 6 th speed
and a couple set screws in the main pulley.
So in the next few days I'll go use my friend's mill and do 5 or 6 things for
the pulleys and power feed.
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NP317
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Re: ROCKWELL 21-122 milling machine REBUILD

Post by NP317 »

I hope you are feeling better, and can stay that way.
Lots of nasty viruses going around these days.
Shop work always helps me feel better. Same to you.
RussN
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

Well, back at it.
In getting ready to fit and adjust the saddle.
I couldn't remember the orientation of the 2 sliding plates
on the top of the knee. So in going through all the combinations( the cutouts
for the cross slide/table feed nut are not equally spaced)
I couldn't find a happy place to where you could see the
knee bevel gears for greasing.
So after fighting with it for a bit, the following is my solution.
See pic.1, both plates top and bottom are oriented with the
longer section toward the column and I put a cutout at the back end
for clearance of the nut about 9/16 to 5/8" wide and 5/8" long.
Pic. 2 & 3 shows how the plates sit when when the saddle is fully fwd
and fully to the column. A little hand manipulation of the plates may
be needed for full coverage in certain positions when doing lots of
longditudal milling.
Pic.4 shows good visual access to the bevel gear.
Attachments
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wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

Well the saddle is fully installed and adjusted.
The hardest part, besides cleaning up dings and burrs along the edges of the ways
was ... getting the saddle to travel the full length of the knee without binding.
It always seem to want to bind as it got close to the column. So from what I was
seeing, I decided to lift the nut up from the surface of the saddle.
After trying many different combinations, I settled on washers under the nut that
gave a .072" spacing.
After all the adjustments, I checked the backlash. It was .002" at the front and
.004 and .005 at the middle and rear.
With the screw in place it hides the bevel gear a bit. But are still able to see and grease it.
Attachments
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wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

I'm working on the table right now.
There are no driil marks or endmill oops.
But there are a lot of dings which I'm going over with a diamond lap to make sure there
aren't any high spots around them.
If all goes well, should have the table on tomorrow.
By the serial # the mill is from 1968. On the underside of the table
the date is cast in: Nov/Dec 1967.
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: ROCKWELL 21-122 milling machine REBUILD

Post by wally318 »

Well the table is on and set-up with all the associated little bits except on the RHS.
The bearing/end of table bracket isn't back from powder coat yet.
The backlash is .005 at the ends and .0085 in the middle.
Will check it again after RHS bracket is installed.
Attachments
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