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1938 Cincinnati 2MH - handles don't move the table anymore

Dope

Cast Iron
Joined
Jan 16, 2016
Hello friends,

I've been using my new-to-me-but-very-old Cincinnati 2MH for a few weeks now. However, tonight, immediately after taking a full-length pass on the X axis, the table suddenly would not move. There was no sound at all, I just suddenly couldn't move the table back for another pass. Both handles turn freely and they are turning the lead screw (the power feed also turns the lead screw) but the table does not move at all.

Anyone have any idea what the problem might be? I'm assuming I need to remove the table and I'm guessing that the nut stripped out or somehow fell out at the extreme end of travel. I'm open to suggestions, pitfalls, tips or tricks of any kind - I've never had a mill apart before. I do have a forklift and such so I'm guessing that the table removal shouldn't be too bad.

Assuming it is a stripped nut, does anyone sell replacements (haha)? I'm guessing I'll have to make one.

Much appreciated in advance, I am very inexperienced in machine repairs so talk to me like I am 5 years old :D

Dope
 
I would think removing the table will answer the questions.

Guessing the nut is not stripped, unless you had a crazy amount of end play to begin with.

A different mill all together, but i just yanked a table off another mill for some maintenance. The feed nut on mine is circular in shape and fits into a bore. A key way keeps the nut from spinning in the bore. If the key were to fall out or sheer off, id expect a similar problem.

I dont have a parts pic in front of me for yours, but maybe something similar.
 
Here is a round one from a 1919 #4 Vertical - from cast iron no less. You can see the notches for a face spanner, but all it has for anti-rotation is a set screw seat

20210520_155431.jpg
 
I would think removing the table will answer the questions.

Guessing the nut is not stripped, unless you had a crazy amount of end play to begin with.

A different mill all together, but i just yanked a table off another mill for some maintenance. The feed nut on mine is circular in shape and fits into a bore. A key way keeps the nut from spinning in the bore. If the key were to fall out or sheer off, id expect a similar problem.

I dont have a parts pic in front of me for yours, but maybe something similar.

I agree with you, I guess I didn't consider that the nut could be round and held in by other means. I googled some pics of Cincinnati cross feed nuts and they mostly seemed to be rectangular-ish externally (probably later designs intended to fix this exact problem, I suspect). I took a peek inside the saddle with a flashlight and I can see something circular rotating with the lead screw when I turn it, I'm guessing that's all it is. Key or set screw backed out. I'm about to start taking it apart now...
 
The manual I sent you should give excellent advice for removing table.

My first wild guess is table dogs weren’t set correctly or present at all and you accidentally began the table removal process by running screw plum out of the nut. A gentle shove on the table while turning screw COULD fix it.


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Okay, spent a few hours taking it apart tonight. I guarantee that none of these bolts and screws have been removed in 83 years, it was a complete nightmare.

However, I have the lead screw free and the feed nut is in fact free of its housing, so that was my problem. Set screw must have backed out and the nut slowly worked its way loose. I've got to take the table off but I'm stuck at the step of removing the gib. There's a screw on the left side of the gib, but it only turns 1/2 a turn in either direction and then stops. I've never seen a gib screw like this, usually they have a locknut but this is literally just a slotted screw. I'm pondering if I should try to slide the table off with the gib in place, but so far it doesn't budge at all. And I've put enough force on that screw that I'm afraid it's going to break something. I've given up for tonight and I'll take a fresh look tomorrow.

Dope
 
Again, I'm dealing with a different mill, but part of the reason i yanked my table off was to fix a stuck gib screw.

I removed the hand wheels from both sides of the table, then both end bearings that attach lead screw to table.

I then set a chain fall over head to take just a little weight up on table, but mostly just to hold table straight as i shoved table off the saddle. I pushed some by hand, but needed a pry bar to assist. Still being captured by dovetail with gib, table needs to be pretty straight.

Once i got table off, i just flipped gib out of the way. Turns out adjusting screw was bent, which is why mine was stuck. Same thing, about 1 turn in either direction, then freeze:
Bridgeport Maintenance Funny Time
 
Again, I'm dealing with a different mill, but part of the reason i yanked my table off was to fix a stuck gib screw.

I removed the hand wheels from both sides of the table, then both end bearings that attach lead screw to table.

I then set a chain fall over head to take just a little weight up on table, but mostly just to hold table straight as i shoved table off the saddle. I pushed some by hand, but needed a pry bar to assist. Still being captured by dovetail with gib, table needs to be pretty straight.

Once i got table off, i just flipped gib out of the way. Turns out adjusting screw was bent, which is why mine was stuck. Same thing, about 1 turn in either direction, then freeze:
Bridgeport Maintenance Funny Time

Excellent thoughts, thank you. I had pretty much decided to do something similar with a chainfall, and then pull it off with a come-along. I'll update next week.
 
All right, here's tonight's update. I've spent the last two days trying to get the table off with no luck. I could at least see that the feed nut had in fact backed out totally, which was good to see (easy fix).

20210523_004412.jpg

I got it so that table is halfway off the saddle and then it just stops, and nothing could move it. I tried taking off the table to the right and to the left but ran into a stop both ways. Turns out, the set screw had backed out but not fallen out, it was actually blocking the table from coming off because there was so little clearance.

20210523_004404.jpg

I never thought of that as a problem so I spent an insane amount of time trying to pry that damn table off. I only saw it when I decided to take a picture inside the tiny little gap (about 1/8") under the table, and I could just spy some threads in the shot:

20210523_004556.jpg


I ended up cutting off the set screw with a sawzall that could juusttt reach. I was then able to push the table almost all the way off but it stops again with only a few inches to go. This is where I'm stuck now, the table simply will not go off the end of saddle.

20210523_014057.jpg

20210523_014052.jpg

I tried everything, including putting upwards pressure on the end of the table with an engine hoist and a forklift. Also put some downward pressure on it by letting it rest on one of my fabrication tables. Tried using a come-along to pull it off, I nearly pulled my wall down with it. I resorted to literally ramming the table off with my forklift and it didn't budge, I only managed to almost knock over the mill. It's REALLY stuck on there. I assume that the ends of the table have the least wear, and the gib is adjusted to take up the larger wear in the center of the table, but it's causing it to bind up at the very end of the travel. I can't get the gib screw out, I even made a flathead impact bit and tried an electric impact to take it off, but the screw doesn't budge. I may try my big boy pneumatic impact tomorrow but I kinda didn't want to break the screw off. I guess it doesn't really matter, the screw doesn't move anyway.

Unless anyone has a magic wand idea to get the table the rest of the way off, I suppose I'll just screw the feed nut back on, replace the set screw and reassemble the machine.
 
Ever remove gib?

They make super-dooper taper locks

(the further you move the table in relation to the fat end of the gib, the tighter the table will be stuck - assumes gib is moving with table)

Cincinnati liked 5/32" taper per foot on their gibs - that's another .013" per inch
 
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Looking at your pics, I think I see the gib. With the table stuck over the top of the thicker part of gib. If that's right, I'm thinking the table is stopped over the adjusting screw. If its possible to shove the table either off, or atleast towards the other side, you might get better working access to the stuck screw.

If your table didn't jump or chatter on various cuts during operation, you might be ok to put it back together. I'd much prefer having total control of a working adjustable gib though, and you do have it a part this far . . . Just a guess, but no doubt the gib or table adjustment will bother you later with Murphy's Law and such. :D

If you're still getting used to using the machine you could deal with it later when you get more obsessive with certain tolerances. You know how it is, pay now or pay later. :D
 
Ever remove gib?

They make super-dooper taper locks

(the further you move the table in relation to the fat end of the gib, the tighter the table will be stuck - assumes gib is moving with table)

Cincinnati liked 5/32" taper per foot on their gibs - that's another .013" per inch

The gib is still on there, because I can't remove it due to the stuck gib adjustment screw. I believe the screw to be bent as it only moves half a turn and then stops. It's sort of a catch-22 situation, I need to get the table off so I can lay the gib over and remove the screw, but I can't remove the table without removing the screw/gib. The gib stays with the ways by the way, it doesn't move with the table.
 
Looking at your pics, I think I see the gib. With the table stuck over the top of the thicker part of gib. If that's right, I'm thinking the table is stopped over the adjusting screw. If its possible to shove the table either off, or atleast towards the other side, you might get better working access to the stuck screw.

If your table didn't jump or chatter on various cuts during operation, you might be ok to put it back together. I'd much prefer having total control of a working adjustable gib though, and you do have it a part this far . . . Just a guess, but no doubt the gib or table adjustment will bother you later with Murphy's Law and such. :D

If you're still getting used to using the machine you could deal with it later when you get more obsessive with certain tolerances. You know how it is, pay now or pay later. :D

Yeah that's the other thing, there was a fair amount of table vibration when making cuts, along with a poor surface finish. It wasn't terrible but it sort of make sense now, knowing that the gib adjustment screw is stuck. And yes, the table is stuck right at the adjustment screw. I'm working with the manual that specifies to take the table off to the left but you're right, I could try pulling it from the right side. The problem actually is, I've tried that and I need to secure the mill to the floor because if I try to pull it to the right, the mill just slides across the floor. I didn't have any concrete anchors long enough so I've got some on order (along with some roll pins and set screws for things I've destroyed along the way). More to come later this week...
 
I’ve intended to look at MY copy of the manual you have to try & give you another perspective but flat out haven’t had time.
I don’t remember, but does that mill have opposed gib screws?

Meaning-one pushing from each end? Instead of ONE screw pushing AND pulling one end of gib.

It should not be this hard. Fact that it is screams “something is WRONG!”


Sent from my iPhone using Tapatalk
 
I’ve intended to look at MY copy of the manual you have to try & give you another perspective but flat out haven’t had time.
I don’t remember, but does that mill have opposed gib screws?

Meaning-one pushing from each end? Instead of ONE screw pushing AND pulling one end of gib.

It should not be this hard. Fact that it is screams “something is WRONG!”


Sent from my iPhone using Tapatalk

Nope, just one gib screw on the left side of the table. I agree that it shouldn't be this hard but I think it all comes down to this stuck/bent gib screw. To be clear, I an open to any other ideas, there are a lot of very knowledgeable people here.
 
I an open to any other ideas, there are a lot of very knowledgeable people here

Be nice if you could start over and follow their instructions like here from M-786 Parts and Service

Gib removal is up there near the top of the steps required to get table off

Cinc Table Reove.jpg
 
There is so much wear in the table ways that it is causing you to bind up at the ends of the table where the ways are not worn. You have to somehow jack the table back to the middle or midways onto the saddle. Then work on getting the gib screw out to get the gib removed. This is the only way you are going to get the table off without destroying your table, gib and saddle, and you insanity! And if you break off the gib screw, no problem, make a new one. Done this many times over the years of machine tool rebuilding.
 
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