Rockwell milling machine-removing COLUMN

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

Rockwell milling machine-removing COLUMN

Post by wally318 »

I have a rockwell model 122. Both horizontal/vertical.
The knee is stuck near the bottom of the column
The bottom gib screw fell out and gib is wedged down.
I have the mill on its back with table and cross slide off.
I'm trying to take off the base so that I can use a jack to slide
the knee off the bottom of the column.
With all 6 bolts out from under the base, the base won't budge
off the column.
It feels like something is still holding it there.
Even using some leverage on the front of the base to underneath
the knee, a gap barely opens up under load.
Some help/input please.
Russ Hanscom
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Re: Rockwell milling machine-removing COLUMN

Post by Russ Hanscom »

Ok, so you say the gib is wedged in. Possibly one of the problems. Any way you can get the lower gib screw back in and loosen the gib? Might be a start in the right direction. If the gib is wedged in, the knee is not going to move.

Please post some pictures. I do not have one of these mills, but I have plenty of machine tools with gibs so I do know how they function.
pete
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Re: Rockwell milling machine-removing COLUMN

Post by pete »

Wow, fwiw you have my sympathy. A wedged knee gib can easily go one of two ways. One you get it out with almost always a great deal of effort, or two your going to scrap the whole machine and there a very high chance of that if you do things wrong. The search function on the Practical Machinist forums is useless, instead do a DETAILED Google search using various terms such as wedged or broken knee gib. This has been covered more than once over there and Forest Addy (one of the members) has a whole lot of detailed information about the best methods. Start using any force and you are going to make things a whole lot worse.
wally318
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Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: Rockwell milling machine-removing COLUMN

Post by wally318 »

Thanks for the input.
The knee was stuck about 3" from the base.
The lower gib screw felt like it wasn't there, or the head was sheared off.
So consequently my need to remove the base.
This morning I went to work and picked up a bottle jack, some thick
aluminum plates, and some metal bars.
First I tried to push the knee down toward the base w/o removing the base
to see if the gib would unwedge. The mill is lying on its back.
I used the bottle jack and plates and metal blocks, pushing against the round
overarm using V blocks to stabilize the plates and keep everything centered.
No luck. With a reasonable amout of pressure build up nothing was budging.
So decided on path of least resistance and damage. GET the BASE off.
Put a couple bolts in the base mounting holes and used the long bar as leverage on the
bolts in shear between the base and column. In doing so I noticed the base was sliding against the column
around a pivot point- a seventh bolt that I didn't know about.
It was hidden on the underside of ribs in the casting shaped like 3 sides of a box with the
open side facing down. So hiding the bolt head. With that out of the way, it was down
to the business at hand.
\The gib screw was there all the way at the bottom of the recess.
The domed head for some reason wasn't contacting the bottom edge of the gib.
Maybe the head was too small in dia. it was contacting the outboard side of the gib.
With the bolt out of the way, I tried knocking the protruding bit of gib back with
an aluminum block. Didn't want to go.
So ... I took a chisel and ground a nice solid flat nose and the gib was pushed back
quite quickly. With the gib out of the way the knee came loose with a quick tap.
Before the base goes back on I'll give the bottom foot of the column ways a good going over.
Easier to do with it flat on its back and the base off. They come all the way down within
1-1/4" from the inside of the base.
Before I put the base on I'll mount the drum switch for the horizontal motor inside the column.
The holes are already drilled. Just need to wire in a power cable and mount it.

This is all part of a complete overhaul/rebuild/repaint project.
So everything that needs doing is getting done before paint.
Before I worked on the knee I adapted a Parkson slotting head that I brought in
from England to the horizontal spindle.
There's lots more. If you're interested I'll share.
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Harold_V
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Re: Rockwell milling machine-removing COLUMN

Post by Harold_V »

wally318 wrote: Sat Sep 19, 2020 7:58 pm If you're interested I'll share.
Please do! Any pictures?

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 milling machine-removing COLUMN

Post by wally318 »

I will post a few pics later today, re: the thread at hand.
For the sake of anyone searching in the future.

Harold, should I start a new Thread/subject on the rebuild?
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Harold_V
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Re: Rockwell milling machine-removing COLUMN

Post by Harold_V »

Might not be a bad idea, with a title that clearly advises the readers of the purpose. Makes it easy for others to find information when they do a search.

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

Re: Rockwell milling machine-removing COLUMN

Post by wally318 »

Here's a couple pics re: thread at hand.
The 1st pic is of the bottom of the base.
The ribs near the bottom forming 3 sides of a box were what was
hiding the 7 th bolt. With that off base came off easy.
2 nd pic is of damage to the gib.
I will lap the contact areas on the granite block with some
320 and 600 paper.
After I go over all the dovetails for the knee and column
and address any issues, although at 1 st glance they look real
good. I will test fit the gib and adjust for proper slide/play.
If it looks like I have enough room I may just grind the end of the gib shorter.
The gib was damaged because somehow the head of the bolt came off the
end of the gib and wedged itself on the outside of the gib.
You can see that in the pic. Thats the part of the gib length I would grind out.
Attachments
P1040292.JPG
P1040291.JPG
pete
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Re: Rockwell milling machine-removing COLUMN

Post by pete »

From some of the horror story's I've read on the PM forums about stuck knee gibs I'd say you got very lucky.
wally318
Posts: 260
Joined: Sun Jun 05, 2011 1:06 am
Location: Kelowna, British Columbia

Re: Rockwell milling machine-removing COLUMN

Post by wally318 »

Thats almost exactly what I thought.
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