8x30 Milling Machine Restoration

[Mark Early]

hmmm, didn't see the photos, trying again

 

[Mark Early]

How do you remove the drawbar from the spindle, and do you have any photos of how you removed the bearings? I'm just trying to see why my collets won't draw up the end mill tight. I have the quill assembly out of the machine and the draw bar is captive by something. It's a 2001 Enco 8 x 30 from MSC I bought new. Thanks, Mark Early

 

[Radials]

I though at first it was the drawbar as well. It'll just pull right out if you lift it up, but yours is stuck? To me the setscrew looks correct in your picture. Just enough to keep the collet from spinning while tightening the drawbar. It does take two wrenches to tighten the drawbar on these mills since there no spindle brake. Are you using two? I'm not really too sure as to what is keeping yours in the spindle. Can you actually see the end of the bar? There should be some threads visible unless something is threaded onto it?

Nick

 

[MikeInOr]

Yes, the drawbar just pulls out the top of my Husky 8x30 mill. I assumed most 8x30 mills are similar.

Let me preface this by saying I am no expert but "I" would be tempted to try to gently clean up the inside of the spindle. Maybe some steel wool or scotch bright. Nice job on the picture by the way. I will confess to not having looked up the center of any other spindles but the set screw doesn't look out of whack to me either. The bottom of the draw bar looks unusually rough... almost like a previous owner might have broken off the bottom threads? I would definitely recommend pulling the draw bar out and looking at it. I would appreciate a picture if you do so. What happens when you try to pull the draw bar straight up? Does it catch on something?

Radials did a really nice rebuild on his 8x30 and as such is much more knowledgeable with them than I am. After reading his response several times I believe he is implying that a broken off top of a collet or other tooling might be on the bottom threaded portion of the draw bar which would explain both why you can't remove the draw bar and why you can't get anything tight. Now that I think about it this does make perfect sense! If this is so your next question will be: How do I fix it? For which I think that you may have to cut off the top of the draw bar then slant the mill head to the side so you can pull the draw bar out the bottom of the spindle once the top hex has been sawed off.

I know that replacement drawbars can be had for quite cheap on ebay if you end up needing to replace yours.

I am really just guessing here... I look forwards to seeing what others have to say on the subject.

Edit: Another thought, if the draw bar is stuck and there is something foreign screwed onto the bottom of the draw bar threads maybe you could put a rod of round stock up the spindle and lower the spindle or raise the knee so that it puts pressure on the foreign object to keep if from spinning while unscrewing the drawbar from the top counter clockwise? Maybe even use an impact wrench to try to unscrew the draw bar with the rod applying tension on the foreign piece?

Edit2: A higher resolution picture of the inside of the spindle might make it easier to decern if there is something foreign screwed on to the bottom of the draw bar... if possible.

Edit3: The threads on the end of a R8 draw bar are 7/16" x 20tpi. A 1/2" schedule 40 iron pipe has an ID of .625". Using a 1/2" pipe up through the spindle instead of the rod described above might allow you to actually pinch the foreign object between the pipe and the inside of the spindle while leaving the draw bar free to unscrew. I would still use the table and raise the knee to provide the upwards pressure on the pipe. I think this is the approach I would try first if you confirm there is something stuck on the bottom of the draw bar. Putting the pressure directly on the foreign object instead of the bottom of the draw bar should be much more effective in capturing the object and keep it from spinning while unscrewing the draw bar.

 

[Mark Early]

I though at first it was the drawbar as well. It'll just pull right out if you lift it up, but yours is stuck? To me the setscrew looks correct in your picture. Just enough to keep the collet from spinning while tightening the drawbar. It does take two wrenches to tighten the drawbar on these mills since there no spindle brake. Are you using two? I'm not really too sure as to what is keeping yours in the spindle. Can you actually see the end of the bar? There should be some threads visible unless something is threaded onto it?

Nick

Hi Nick,
Thanks for the information. I was able to pull everything apart yesterday. I have the quill, spindle and drawbar assembly in a vise (gently & padded). There is something that the drawbar is secured to above the top of where a collet sits. I kept spraying and dripping liquid wrench on the spindle and drawbar being careful not to get any on the bearings. After a while I noticed that the collets would seat a little more deep in the spindle. I think the drawbar and spindle come out as an assemble when the bearings are pressed out. I'm not sure I want to mess with that at this point. What did you do with yours to get the bearings out and repack or replace? I saw there were comments about using heat to expand the quill and special races turned to match the bearings. I had a 12 ton press that I recently got rid of, so not an option for me. I think I'll fiddle with the quill to see if it was just dirty, rusty and dusty from not using it for a couple of years. Can't believe I've had the machine for over 20 years now.
Mark

 

[Radials]

Hi Nick,
Thanks for the information. I was able to pull everything apart yesterday. I have the quill, spindle and drawbar assembly in a vise (gently & padded). There is something that the drawbar is secured to above the top of where a collet sits. I kept spraying and dripping liquid wrench on the spindle and drawbar being careful not to get any on the bearings. After a while I noticed that the collets would seat a little more deep in the spindle. I think the drawbar and spindle come out as an assemble when the bearings are pressed out. I'm not sure I want to mess with that at this point. What did you do with yours to get the bearings out and repack or replace? I saw there were comments about using heat to expand the quill and special races turned to match the bearings. I had a 12 ton press that I recently got rid of, so not an option for me. I think I'll fiddle with the quill to see if it was just dirty, rusty and dusty from not using it for a couple of years. Can't believe I've had the machine for over 20 years now.
Mark

Mark,

So just to clarify, it seems there was a time you used this machine and there was no trouble with the collet installation? Honestly I don't believe pressing the spindle out of the quill is necessary. The drawbar is a wear component on mills and having to go through all this just to change it doesn't seem logical. When I had my quill apart I didn't notice anything indicating that there was suppose to be an internal retainer on the drawbar. Mike's suggestion to put pressure on whatever you see up in the spindle threaded onto the drawbar to thread it out seems like a good method. Maybe even going as far as supergluing a modified rubber washer or some sandpaper to the end of the pipe/tube if you need some more grip on it.

Nick

 

[Mark Early]

Mark,

So just to clarify, it seems there was a time you used this machine and there was no trouble with the collet installation? Honestly I don't believe pressing the spindle out of the quill is necessary. The drawbar is a wear component on mills and having to go through all this just to change it doesn't seem logical. When I had my quill apart I didn't notice anything indicating that there was suppose to be an internal retainer on the drawbar. Mike's suggestion to put pressure on whatever you see up in the spindle threaded onto the drawbar to thread it out seems like a good method. Maybe even going as far as supergluing a modified rubber washer or some sandpaper to the end of the pipe/tube if you need some more grip on it.

Nick

 

[Mark Early]

Hmm, I will check through all my collets to see if any are missing something. Thanks for all the comments! Soaked it overnight with penetrating oil and tried tapping on it with a brass punch so as not to bugger up the bottom of the drawbar. Doesn't seem to want to move. Dennis at the MSC machine support in Atlanta seemed to think maybe it is a washer that got rusted onto the drawbar. I'll try some other tricks to free things up. Does anyone know of a place where I can have new bearing installed? I sold my 12 ton press recently and probably would not want to tackle this job anyway.

 

[Mark Early]

Mark,

So just to clarify, it seems there was a time you used this machine and there was no trouble with the collet installation? Honestly I don't believe pressing the spindle out of the quill is necessary. The drawbar is a wear component on mills and having to go through all this just to change it doesn't seem logical. When I had my quill apart I didn't notice anything indicating that there was suppose to be an internal retainer on the drawbar. Mike's suggestion to put pressure on whatever you see up in the spindle threaded onto the drawbar to thread it out seems like a good method. Maybe even going as far as supergluing a modified rubber washer or some sandpaper to the end of the pipe/tube if you need some more grip on it.

Nick

Hi Nick,

I get the dummy of the year award, but thanks to all the comments I finally figured it out. The last job I used the 3/4 inch collet while milling a weld bead off a large trailer hitch extender for my camper. When I pulled the collet out I didn't notice that the insert on the top of the collet was still on the drawbar, ha! Here is a photo of a 7/8 and 3/4 collet side by side. The 3/4 collet insert is missing and must be the piece on the end of the drawbar. I've been running bridgeports since I was 18 and am now 67 and I have never seen a collet do this. I'll have to get creative and somehow get ahold of that insert and remove it. All these enco collets will then go into the steel recycle bin at the dump. Thanks again for the help!

 

[Mark Early]

what kind of dolly are you using to move the machine on? Looks like it must be pretty robust.