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#4 morse taper sticks in spindle?

M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
Not exactly machine reconditioning but I thought the experts here might be able to help.
I have a new to me Erlo drill press with a #4 morse taper spindle and the Rohm drill chuck that came with the machine (nice) becomes very stuck in the spindle after drilling even a small hole.
The machine has an "auto-eject" feature which is actually quite nice to use but not when the taper sticks so hard I have to use a hammer and wedge to release. None of my other taper sleeves stick like this one they all release with the auto eject. So it does seem like it is the drill taper and not the spindle.

Any ideas on how to make it release a bit easier?
 

hvnlymachining

Cast Iron
Joined
Jun 21, 2019
Location
St.Onge
The better a taper "sticks" shows just how matched and polished the two tapers are.
If sticking is troublesome try sanding lightly with coarse sandpaper, the goal is to get some scratches that will hold oil and air to allow an easier release.
 

Paolo_MD

Stainless
Joined
Apr 6, 2013
Location
Damascus, MD
The taper of many MT drill bit is interrupted by a rebated band roughly in the middle. This reduces significantly the contact surface between the male and female taper.
Perhaps, you might do the same with the taper of your chuck.

Paolo
 

52 Ford

Stainless
Joined
May 20, 2021
If you try the sandpaper thing, be careful you don't take off too much material.

You are NOT trying to reduce the diameter, just reduce the amount of contact area. 60 grit or coarser would be best, I think.

As Paolo said, it's not uncommon for the middle section of the taper to be turned down.

Maybe turn the middle section down.
 

M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
Ok, good suggestions. I will try the coarse sandpaper first and then try the relief if it still sticks too much. The current taper sleeve is very smooth and almost polished so maybe that is the problem.
 

Limy Sami

Diamond
Joined
Jan 7, 2007
Location
Norfolk, UK
#4 morse taper sticks in spindle?

On reading the thread title I was gonna say - it's what they're supposed to do ;) however I've had trouble with so called auto ejectors and that was only on # 2 & 3 - larger could only mean more trouble.
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
I recently scrapped a big Asquith OD2 radial......had a taper stuck in the spindle for at least 40 years......the self eject wouldnt move it,and also blocked the slot for a drive in drift........anyhoo,sitting in the scrapbin,I though Ill salvage the QD adaptor stuck in the spindle.....14lb hammer one side of spindle,smart whack other side with a 7lb hammer ,out comes the QD adaptor......releasing a taper 101.
 

M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
Limi,
I realized after that I could have worded the title better. It is doing what it is supposed to do but too much of a good thing can wear you down.

JohnK, not sure if that would be good for the spindle on a regular basis? Seems like a bad design if the drift slot was blocked? I have a slide hammer that I made from a drift and it is not enough to eject this particular sleeve. I have to use a hammer.

How large would the relieved area be on a typical sleeve? I have over 75 #4 taper drills set up for my machines and not one of the sleeves has a relief. Most have sleeves while some of the larger drills are factory #4.
 

Rickyb

Cast Iron
Joined
Jan 21, 2011
Location
Troy mi
I recently scrapped a big Asquith OD2 radial......had a taper stuck in the spindle for at least 40 years......the self eject wouldnt move it,and also blocked the slot for a drive in drift........anyhoo,sitting in the scrapbin,I though Ill salvage the QD adaptor stuck in the spindle.....14lb hammer one side of spindle,smart whack other side with a 7lb hammer ,out comes the QD adaptor......releasing a taper 101.

This has been the standard procedure for removing steering and tierod arms from heavy truck spindles for a century. But there were no bearings to worry about.
 

52 Ford

Stainless
Joined
May 20, 2021
I recently scrapped a big Asquith OD2 radial......had a taper stuck in the spindle for at least 40 years......the self eject wouldnt move it,and also blocked the slot for a drive in drift........anyhoo,sitting in the scrapbin,I though Ill salvage the QD adaptor stuck in the spindle.....14lb hammer one side of spindle,smart whack other side with a 7lb hammer ,out comes the QD adaptor......releasing a taper 101.

Right. Makes the taper go a little oblong and breaks the "sticktion".

Like Rickyb said, that's how you break loose tierod ends on steering knuckles.

Off topic, but the worst time I had knocking a taper loose was on a Lincoln car. They had some sort of retaining compound on the taper. It was a fairly steep taper, too. Big impact on a ball joint press, plus a sledge hammer FINALLY got it loose. Funny looking goop. Not sure what it was that they used.
 

52 Ford

Stainless
Joined
May 20, 2021
Limi,
I realized after that I could have worded the title better. It is doing what it is supposed to do but too much of a good thing can wear you down.

JohnK, not sure if that would be good for the spindle on a regular basis? Seems like a bad design if the drift slot was blocked? I have a slide hammer that I made from a drift and it is not enough to eject this particular sleeve. I have to use a hammer.

How large would the relieved area be on a typical sleeve? I have over 75 #4 taper drills set up for my machines and not one of the sleeves has a relief. Most have sleeves while some of the larger drills are factory #4.

Well, THESE MT4 tools seem to have axial relief slots cut in them. https://i.ebayimg.com/images/g/7PYAAOSwMNhe2IXc/s-l400.jpg Joking. :D

If you have a convenient way to chuck it in the lathe, you could start with a short relief and slowly add to it. At any rate, with MT4, you're only looking a a few inches of relief.

The MINIMUM I would leave is 1" of good contact on both ends of the shank.

As long as it's running true and it doesn't fall out on it's own... whatever works.

Good luck!

Let us know how it goes, if you get a chance.
 








 
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