# BRIDGEPORT M HEAD SPINDLE WEAR PROBLEM



## Currahee26 (Feb 21, 2018)

Greetings. I have an older  round ram, M head Bp mill.  The spindle is so worn out inside that my Morse taper # 2 (MT2) collets go all the way up inside almost to their widest end before they clamp the bit.  So far I can live with this but it consumes almost all of my bit length.  My biggest problem is with a NON COLLET tool, such as my MT2 fly cutter and MT2 keyless chuck.  they literally rattle around inside the spindle even when inserted all the way!  They wont take any milling load and will simply spin off the drawbar.   *Any suggestions*?  If I could find a new M head spindle, I'd just buy it and problem solved.  So far only used ( and probably also wallowed out) ones on line I've seen.  I managed to wrap a very thin tin shim around the shank of the fly cutter and it wedged in OK to work.  Such a contraption would make changing other tools and collets a PITA.......in my opinion.........Thanks for reading


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## markba633csi (Feb 22, 2018)

That's a toughie.  Perhaps a plating shop could plate it back? Or spray-plasma and re-grind. Don't know the cost


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## Hukshawn (Feb 22, 2018)

How different is the m head to a j head? I have a Bridgeport j head sitting on my garage floor I bought for space parts. I used up all the spare parts I needed and I’m left with an empty head, full pulley drive head, and a decent complete R8 spindle I don’t need. If it’ll fit, I’m sure we could make a deal.


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## Ed ke6bnl (Feb 22, 2018)

might be more reasonable to replace the entire head with a J head, I have a round ram with a J head. I got it that way.


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## Hukshawn (Feb 22, 2018)

Well... I have a whole j-head. Albiet, missing most of the innards, mostly the quill power feed stuff. The drive head will need to be torn down, it's very stiff. I have not looked at it all. If there's a mild interest in it, I can take pictures.


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## Bob Korves (Feb 22, 2018)

Currahee26 said:


> Greetings. I have an older  round ram, M head Bp mill.  The spindle is so worn out inside that my Morse taper # 2 (MT2) collets go all the way up inside almost to their widest end before they clamp the bit.  So far I can live with this but it consumes almost all of my bit length.  My biggest problem is with a NON COLLET tool, such as my MT2 fly cutter and MT2 keyless chuck.  they literally rattle around inside the spindle even when inserted all the way!  They wont take any milling load and will simply spin off the drawbar.   *Any suggestions*?  If I could find a new M head spindle, I'd just buy it and problem solved.  So far only used ( and probably also wallowed out) ones on line I've seen.  I managed to wrap a very thin tin shim around the shank of the fly cutter and it wedged in OK to work.  Such a contraption would make changing other tools and collets a PITA.......in my opinion.........Thanks for reading


Wait, doesn't an M head use R8 collets?  Make sure the serial number has a M at the beginning of it.  If it does, maybe try a R8 collet for fit.  If it has a H at the beginning of the s/n, then it a H head and you should talk to me about some nice unobtainium collets I have...


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## chips&more (Feb 22, 2018)

The taper being that worn does not make sense to me. What does is the assumption it has a #2 Morse taper and it probably does not. The M head came with 3 different tapers to my knowledge, a #2 Morse, B&S 7 and a B-3. Sorry Bob, don’t think there was ever a R8 in a M head. I would look again at the taper you have…Dave.


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## markba633csi (Feb 22, 2018)

Yes it could be a B&S #7 which is .720 on the big end- MT2 is .7005


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## Dredb (Feb 22, 2018)

I agree with the last 2 posts, can't see any way the spindle taper could wear like that, it's either been butchered or it's not MT2. In addition to the MT2 and B&S tapers there were also some specials but no R8 on these, the spindle is not big enough. Best thing to do is take a cast of your spindle taper and measure it. A J head would be a nice upgrade for your mill. I use an M head on my non Bridgeport mill, I like it, it's fine but the J head is in a different league altogether.


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## Currahee26 (Feb 24, 2018)

HMMMM!
Some very intriguing ideas and observations!  I'm not sure why I thought/think it's a MT2! I think it may have been the manual I found on it.
It was being used as a drill press and had a non drawbar loaded keyed chuck hammered up into it. (NOT by me!)  It didn't even come with a drawbar! I found one on eBay (Maralice ).  I've been surmising that the pounding just wallowed out the spindle.  Now that I know what B&S  #7 (thanks Markba633csi) size is,  I will either try and figure out how to take a cast (Dredb) and or find a B&S #7 and see if it fits. I have so many other questions about this mill and its normal functions, but for now Ill address the spindle issue.  It had been in the repair shop in Miami Fl at the USOA (US Overseas Airways).  They had GREASED it for years and I had to clean all the oiling ways to oil it properly.  The left and right movement of the table is sloppy but I have tightened it up as best I can for now.  Ill get your advice on that issue later. 
Thanks to you all for your time and help.


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## markba633csi (Feb 26, 2018)

You can hear the machine breathing a sigh of relief: "finally, some people who know how to care for me" 
LOL


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## Currahee26 (Feb 26, 2018)

I replied last night here with NEW FINDINGS, but the post is missing!   hmmm   Oh well, Ill try again.  I re read the manual for the round ram/M head Bp mill and it says that the M head could be ordered with one of three spindles ! Part number 2204820 was a #2 MT, Pn ***4821 was a #7 B& S and Pn ***4822 was a B-3!!   So, I'm going to try a #7 B&S collet first and see what happens.  I wouldn't have looked up the parts list if it weren't for your suggestions about different sized spindles!
SO< thanks again to all who took the time to reply 
dlB


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## Currahee26 (Mar 2, 2018)

WEll, as it turns out gents, the #7B&S taper fits perfectly!  It sticks out of the snout of the spindle almost half an inch more than my MT #2 collets do!
That gives me considerably more force on the clamping and virtually no spin on the fly cutter or drill chuck.
Thank you all again for your time and assistance.
Peace
dlB


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## Shiseiji (Aug 27, 2018)

For others, at the end of this page is a visual test for checking the type of taper:
"M" Head Collet Sizing


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## Currahee26 (Aug 27, 2018)

Thanks for posting this Link on "M" Head Collet Sizing. VERY informative!!  As it turns out my M head came with a spindle that takes #7 B&S collet as I stated in an earlier reply  I was able to find as many as I needed on eBay.  Just had to search a few sellers "stores" to find the listing but it was easy and not very expensive.

Thank again for all input
dlB


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## Shiseiji (Sep 1, 2018)

My pleasure, a small pass it forward.


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## Currahee26 (May 12, 2022)

AS IT TURNS OUT.......THE SPINDLE IS A BROWN AND SHARP #7!!!   A little research determined that some Brideports were equipped with B&S #7 spindles.  Problem solved!!  Thank you all...!


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