Bridgeport M head spindle cap removal

[geshka]

Hello there.
I am refurbishing my BP with M head and stuck on removal this spindle cap. It is rotating freely, I see no any setscrews, there is no any thread underneath. I believe this cap has to be fixed firmly with some cross-pin: there are flats on a sides of this cap to tightening/slackening drawbar. It might be just broken. It is M head with step cone pulleys model.
Wondering, if anybody seen this before and have any clue.

 

[jim rozen]

Left hand thread on that.

 

[M.B. Naegle]

Do you mean the cap is rotating freely independent of the spindle? The only cap's I've seen were threaded on with a left hand thread, I think I see the end of a thread just past the edge of the cap, so it could be that the threads are stripped?

FWIW, not all BP M-heads came with the threaded cap. I've seen at least two that never had the threads and were B&S #7 taper, while my head with a Morse #2 taper has the threads but it missing the cap. I'm not sure if it was a generational thing or they only provided it for the Morse #2 spindles.

 

[geshka]

Do you mean the cap is rotating freely independent of the spindle?

Yes, this cap is rotating independent of the spindle - I can do it with my fingers. It also has a bit of axial move I tried to pull it of and engage some thread underneath if any) - no catch at all. What you see is not an end if the thread, but sort of groove encircling spindle into splines.

 

[geshka]

Left hand thread on that

Hmmm. tried to pull cap off and engage thread at the same time - no luck. May be thread is smashed up...

 

[M.B. Naegle]

Here's my spindle that's missing the cap.

 

[geshka]

Thanks a lot, M.B. Naegle. I will try harder tomorrow ...

 

[Doozer]

My MT2 model has a threaded cap that has 2 wrench
flats and it stamped LEFT ----> with an arrow and a
knurled band. It is hard, so I don't think it is shop made.

-Doozer

 

[geshka]

Thanks folks. Cap was removed - this is what left from the (left) thread

 

[M.B. Naegle]

That's unfortunate, but at least it's not 100% necessary to use the head.

If you want to restore the cap function on that head, perhaps you can turn the threads down, press and pin a steel sleeve on and then re cut the threads and splines? Is there any play between the splines and the pulley? If so I think I'd call it a parts head and look for a better one. They're not getting any more plentiful, but luckily a lot of guys pass them by for the bigger J-head BP's or replacement import heads, so they aren't really rare yet.

 

[geshka]

Is there any play between the splines and the pulley?

Not sure yet, Head is quite bitten up. Packed with awful mix of grease, dust and corrosion. Will disassemble completely and have assessment.

 

[Doozer]

That's unfortunate, but at least it's not 100% necessary to use the head.

If you want to restore the cap function on that head, perhaps you can turn the threads down, press and pin a steel sleeve on and then re cut the threads and splines?....

I would hesitate to sleeve the area and re-theread.
You don't need a sleeve. Keeping it on is tricky
and you remove good metal to make the sleeve
thick enough. Not my first choice.
Just re-cut the threads deeper and make the cap
to fit. Least amount of material and strength removed.

-Doozer

 

[jim rozen]

The reason M heads have that wonky extractor drawbar setup is mostly all of them had self-holding taper collets - and the pusher drawbar eliminated the need to pound the collets out, with the pounding going through the spindle bearings. J heads don't have this feature because R8s are not self-holding.

 

[geshka]

Another obstacle - cannot remove this long screw with depth adjustment nuts. It is corroded and Philips screwdriver in slot is not holding on. I already made several cycles of warming/PBblasting/cooling... not budging.

 

[geshka]

pusher drawbar eliminated the need to pound the collets out

Sorry, Jim. Did not quite understand how it should work, is there any explanation or may be short video

 

[jim rozen]

The drawbar is captive in the top nut, with the left-hand theads. When it's assembled properly, one holds the flats on the lower nut, and unscrews the hex on top of the drawbar. The drawbar can't back out of the top nut and the force pushing the collet out of the spindle (drawbar is now a pusher-bar) is applied such as to tighten, not loosen the coarse left-hand threads on that top nut. Collet pops out of the spindle. There's no force applied via the spindle bearings.

 

[geshka]

thanks Jim. So this not my case,. i was able to pull drawbar out of spindle and nut. It is not captive , I guess. Or something is missing like a locking washer.

 

[geshka]

OK. I am currently at the point when I disassembled everything, only quill is in housing and cross pinion is still there. I cannot move quill for some reason - it is stuck and I afraid to apply a big pressure to move it. Brass half nut is out as well (the one which is seen on the photo)
Is there any "hidden" detent or grab screw under the paint that might be preventing quill to move ?

 

[Doozer]

Looks like the rack pinion is still in there.

-D

 

[geshka]

Looks like the rack pinion is still in there.

Yes, still in there, though it is not locked - i can "wiggle" it a but and move sideways. so , I believe, it is not what is holding quill.