ROCKWELL 21-122 milling machine REBUILD

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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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 I officially made the first chips with the Rockwell mill.
I had to wait till I got a long length pulley tap before starting.
Basically I put a set screw into the motor pulley that I had made.
Set screw was 6mm x 30mm.
I couldn't get a thread all the way to the keyway. Even after
shortening the tap to just under 4 inches, it still felt like it was
probably going to snap. So I erred on the side of caution and
turned the lead part of the set screw into a dowel 8mm long
that snugly fit into the unthreaded part of the hole.
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Harold_V
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Re: ROCKWELL 21-122 milling machine REBUILD

Post by Harold_V »

wally318 wrote: Fri Jan 13, 2023 9:28 pm I erred on the side of caution and turned the lead part of the set screw into a dowel 8mm long
that snugly fit into the unthreaded part of the hole.
While a little longer than normal, that's a dog point set screw. They're also available as a half dog---which is half the length of a dog point. Well done!

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 »

The last few days just been tinkering in the shop. Some work to the lathe and fitting/fine tuning
pcs for the vertical head. Just a few pcs left to scrub and clean.
Basically killing time. On Sat. got to head down to Oroville to pick up Abec 7 bearings for the quill.
And sometime this week I was promised the powder coat should be done.
Then I can put the mill on the stand.
Set up the RH end of the table w/power feed.
Finish off the vertical head.
Install covers and handles.
After its done will be a surprise.
All the accessories I have adapted to this machine.
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, finally got the powder coating back today-15 parts.
That was about a 3 months wait at least.
So, the mill is on the stand and leveled.
The 4 bolts to the mill base-really awkward.
Was tightening down the last bolt and noticed
that I forgot to put in the wood shelf into the stand
first. There was no way I was taking off the bolts re/re.
So I cut the shelf 60/40 and put it in through the door.
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 table/power feed is complete and up and running.
Even though I had test fitted everything pre-assembly, it didn't go
together as smoothly as I hoped. When I bolted on the RHS table
endcap/bearing brkt. The screw started to bind up within about 5-6
inches of travel to the the end of table.
The concusion I came to was that when I shimmed up the bronze nut
to smooth out cross slide travel, it put the table screw off center with
the endcap bearings. So I decided to slot the holes in the brackets
and tighten up the brackets with the screw in a neutral/relaxed position.
From there everything was straight forward.
This power feed unit is the same as the import model that Servo sells/lists
on their own website. But can be gotten from other sources like Shars etc.
for a lot less money.
I forgot to add this last night.
X axis backlash is now .0045" @ RH end and .007" @ center and LH end
with the RH bearing bracket installed.
Attachments
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Last edited by wally318 on Sun Jan 22, 2023 11:28 pm, edited 2 times in total.
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 »

Tomorrow I'll finish assembling/test run the vertical head.
I wasn't able to go down to Oroville today to pick up the new bearings
so will assemble with the old ones.
Will pull the quill and install new bearings after next weekend.
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 vertical head has motor and pulleys.
Just needs the fine feed installed.
Gave the motor a test run through all the speeds.
The AX 25 belt is just a tad tight for quick belt/speed changes.
Is also quite noisy at top speeds.
The motor is a 1 Hp leeson 1140 rpm and with some custom sizing
on the new pulley will get me 235 to 3950 rpm.
Will check that out with the tach tomorrow.
Will go and check out A belts and find one 1/2 inch longer
also one 1 inch shorter for speed #5. The pulley is smaller
on that size at the motor for the speed I was shooting for.
Don't have any more travel @ motor mount pivot to take
up the slack.
When I was prepping the pulley housing for powder coat,
I opened up the hole at the drawbar at the front side.
You can just sneak a V-belt at the front side of the hole.
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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 picked up an A24 and A26 belts.
They are a bit quieter than the AX cogged belt.
But the difference from low to top speed is huge
in terms of how loud it gets.
I think all 4 bearings may need replacing.
I'll see what difference the 2 bottom ones make
after I get them this weekend.That will give me and idea.
The 1 inch longer belt make speed changes quite a bit faster.
And it turns out I needed a shorter belt for both speed 4 and 5.
The stock chart says 245-470-780-1620-2940 and 4200 for 1140 motor
I tached each speed and got 235-490-775-1410-2530 and 4165
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 everythings on, except the new bearings for the quill.
As you can see from the pics of the quill parts and the fully assebled pic.
This is a 1 off custom setup. I bought a worm/wheel off ebay from China
And picked a ratio that improved the 76 handwheel revs to travel 2.6 inches
to 27-1/3 revs. But the best part is that the backlash is less than.001" in
1 direction and about.005" in the other.
One of the ways that that was acheived was by eleminating the clutching
mechanism from fine feed to drilling.
So if a lot of drilling needs to be done all it takes is to loosen 2 set screws
and the handle and worm slide out. And can be set up just as quickly to get
fine feed again. The stock fine feed setup on the Rockwell mill was probably
its weakest point with the aluminum gear and a cone clutch that was prone to
slippage, besides not having a feed dial and a very tiny handwheel/handle.
I put on a nice sized handwheel with a dial off a Bridgeport that rotates by
friction with a delrin bushing so is zero-able.
The handwheel feeds @ .092 to.096" per rev. I think there must be some wear
in the quill rack gear maybe.
The dial has 200 graduations, so .00046 to .00048" per graduation.
For most things that would be good enough. If more accuracy need dialing feed
with the knee or a dial indicator will get the job done.
The vertical head weighs 154 pounds with motor/pulleys.
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Last edited by wally318 on Tue Jan 24, 2023 8:14 pm, edited 1 time in total.
djjh87
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Location: florida

Re: ROCKWELL 21-122 milling machine REBUILD

Post by djjh87 »

Very nice job on the restoration. I always though the Rockwell mill vertical/horizontal is perfect mill for a small shop if space is limited. Jim
No problems just solutions.
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 »

Thank You.
I also came to that conclusion.
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 I did the first official project today.
Made a drive side dropout for a dirt jumper bicycle frame
for a fellow I know at a local bike shop.
The frame is new and has been sitting in a box for 15 years
and unsellable on account of the missing part.
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