Tutorial for head disassembly?

D

DMS

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I finally got my VFD so that I can run my mill now. I powered it up this evening; when I bought it I knew there were some issues with the head (it's noisy). Its a bit noisier than I remembered, so, in order to keep my neighbors happy I am going to have to dig in and figure out what the problem is. I did clamp up a 3/4" piece of drill rod in a collet and put a DTI on it. Pushing on the bar there was no measurable movement, turning the spindle by hand in neutral I could not measure any runout (well, maybe 1/4 div on a 0.5 though dti), so I don't think it is the bearings.

I'm thinking my next step is to remove the motor and top part of the head. I am hoping somebody has a link to a tutorial on dismantling a variable speed head. Barring that, if anyone has done this, where do I start? I know the reeves drive creates tension on the belt, so should I wind the speed up to high and then just pull the motor bolts, or is the another order to do things?

DMS
 
Wow, that's a great walkthrough. Mine is a variable speed head, but it seems like everything below the reeves drive is the same. I also found some instructions that say to wind the speed down to the lowest setting. Guess I'll give that a try tomorrow.

DMS
 
Hi, glad it helped out.
I had some spare time so I went looking for them for you. I remembered them from when I had been looking at them to convert my mill to power down feed on the quill, but think I will just keep looking for a head unless I change my mind again. LOL
This one is a brilliant right up
http://home.comcast.net/~tom.jelly/j head rebuild web page/j head rebuild.htm

I haven't followed any of these links but came across them in my search
http://bridgeport.askmisterscience.com/bridgeportlit.htm

And another
http://www.neme-s.org/Shaper Books/...g Machine Parts Diagrams Series IJ and 2J.htm

A video for removing the complete head
[video=youtube;HFE_nXQCH6E] http://www.youtube.com/watch?v=HFE_nXQCH6E&feature=related [/video]

This is another guy with a similar problem and it can be the belt in some cases causing the problem.
http://www.cnczone.com/forums/bridgeport_hardinge_mills/6291-noise_bridgeport_2j_head_audio.html

from link
A belt will typically make noise if someone stalled the machine and the motor varidrive kept turning causing a low spot.
Also I have often seen that the bearing that is in the front stationary vari disc goes bad and starts to eat through the vari disc.
Remember the "clutch" teeth you saw? When new, they actually engage each other about half way down. As they wear, they go deeper untill they bottom out. Eventually they will have slop (play) and can be a source of noise. Try raising the back gear handle a bit further up to engage the clutch teeth a bit more and see what happens.
My customers are typically commercial machine shops. It is cost effective to just replace the discs. It gives them a machine that will not need me a lot longer and my office charges $120.00 per hour for me. That makes a difference also.

George W.
Click to expand...

And here is a parts and operation manual
http://www.babinmachine.com/BPTFULLMANUAL.pdf

And 2 others
http://www.shophardinge.com/kneemillparts.aspx

Another bit of info
http://bbs.homeshopmachinist.net/showthread.php?t=42594

Hope that helps out, as I am like you and have no hands on experience with these heads myself.
That should keep you busy for a while though, LOL

Dave
 
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Thanks for all the links. As it turns out, most of the import manuals as well as the BPT manuals have the info I was looking for in the maintenance section because you need to do it to replace the belts. Guess I was just making things hard on myself. In any case, I have most of the top half of the mill disassembled, and I think I have localized the noise to the front pulley assembly. Once I get that apart I guess I find out what the damage is.

DMS
 
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