Pillar Drill Problems - UK Vintage Radio Repair and Restoration Discussion Forum

Hermit6345 · 24th Aug 2017, 10:15 am

Not exactly Vintage, but old. I have a pillar drill in my workshop. It has a Jacobs chuck which fits into the Morse taper on the drill. The problem is that when the drill bit hits resistance, the chuck falls out! I don't have any drill bits with a Morse taper, so I can't check if that works OK. In the back of my head I seem to remember that a bodge is to use a centre punch and punch some pock marks over the taper on the Jacobs chuck. That seems a bit harsh to me. The drill is an inexpensive Draper model, but is fairly well put together. Can anyone suggest a fix for my problem, short of suggesting that I get a new drill. TIA

M0FYA Andy · 24th Aug 2017, 10:24 am

If you don't have a need to swap things around, clean the tapers well and apply some Loctite before reassembly?

Andy

Station X · 24th Aug 2017, 10:51 am

Are you using good drills, or are they ground off centre, which in the case of a large diameter drills, will set up vibrations loosening the taper?

Using engineer's marking blue will enable you to find high any high spots on the male taper, which can be stoned away. With Jacobs chucks the taper can be changed for a new one so long as you have access to a suitable press.

You may find that your local model engineering society has Morse Taper reamers which can be used to "clean up" the internal taper. Be very careful though as removal of even a small amount of material will enable the male taper to enter much further.

If you're really desperate use grinding paste to grind the two tapers together.

The use of centre punch marks or adhesive is a bodge.

These taper fits were meant to be assembled and disassembled thousands of times and should be a very tight fit. To split the taper a wedge is tapped into a slot in the shaft, or in the cases of lathes a rod is inserted into the hollow shaft.

Refugee · 24th Aug 2017, 11:50 am

After cleaning the taper have you tried lowering it firmly onto a block of wood to push it in a bit harder?

Boater Sam · 24th Aug 2017, 12:49 pm

Check that the female taper has not split if its a cheap drill press. Ensure the end of the chuck taper is not bottoming in the drill column, it may be just too long.
Clean and degrease both tapers, a rub with emery cloth is a good move.
Fit chuck taper wet with water and smack it in with a block of wood.
Should then lock in.

Hermit6345 · 26th Aug 2017, 10:42 am

Thanks for all the replies. A few things that I can check. I never thought about engineers blue. Takes me right back to my apprentice days 56 years ago. I definitely will not use the centre punch solution! Thanks again.

24th Aug 2017, 10:15 am	#1
Hermit6345 Rest in Peace Join Date: Oct 2006 Location: North Wiltshire, UK. Posts: 638	Pillar Drill Problems Not exactly Vintage, but old. I have a pillar drill in my workshop. It has a Jacobs chuck which fits into the Morse taper on the drill. The problem is that when the drill bit hits resistance, the chuck falls out! I don't have any drill bits with a Morse taper, so I can't check if that works OK. In the back of my head I seem to remember that a bodge is to use a centre punch and punch some pock marks over the taper on the Jacobs chuck. That seems a bit harsh to me. The drill is an inexpensive Draper model, but is fairly well put together. Can anyone suggest a fix for my problem, short of suggesting that I get a new drill. TIA

24th Aug 2017, 10:24 am	#2
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: Pillar Drill Problems If you don't have a need to swap things around, clean the tapers well and apply some Loctite before reassembly? Andy

24th Aug 2017, 10:51 am	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Pillar Drill Problems Are you using good drills, or are they ground off centre, which in the case of a large diameter drills, will set up vibrations loosening the taper? Using engineer's marking blue will enable you to find high any high spots on the male taper, which can be stoned away. With Jacobs chucks the taper can be changed for a new one so long as you have access to a suitable press. You may find that your local model engineering society has Morse Taper reamers which can be used to "clean up" the internal taper. Be very careful though as removal of even a small amount of material will enable the male taper to enter much further. If you're really desperate use grinding paste to grind the two tapers together. The use of centre punch marks or adhesive is a bodge. These taper fits were meant to be assembled and disassembled thousands of times and should be a very tight fit. To split the taper a wedge is tapped into a slot in the shaft, or in the cases of lathes a rod is inserted into the hollow shaft. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

24th Aug 2017, 11:50 am	#4
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,554	Re: Pillar Drill Problems After cleaning the taper have you tried lowering it firmly onto a block of wood to push it in a bit harder?

24th Aug 2017, 12:49 pm	#5
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Pillar Drill Problems Check that the female taper has not split if its a cheap drill press. Ensure the end of the chuck taper is not bottoming in the drill column, it may be just too long. Clean and degrease both tapers, a rub with emery cloth is a good move. Fit chuck taper wet with water and smack it in with a block of wood. Should then lock in.

26th Aug 2017, 10:42 am	#6
Hermit6345 Rest in Peace Join Date: Oct 2006 Location: North Wiltshire, UK. Posts: 638	Re: Pillar Drill Problems Thanks for all the replies. A few things that I can check. I never thought about engineers blue. Takes me right back to my apprentice days 56 years ago. I definitely will not use the centre punch solution! Thanks again.