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View Full Version : Mounting a drill in the tailstock



Tony Ennis
01-02-2011, 08:21 PM
I'd like to be able to drill in the lathe.

I have seen some Jacobs-style chucks having tapers and others having threads. Does it matter which style I get? The other end will be MT2 to fit in the tailstock.

How often do you put the chuck in the headstock and use a fixture to hold the work?

Or, is this all obsolete and everyone just uses a drill press or mill?

J Tiers
01-02-2011, 08:57 PM
I drill in the lathe all the time, for parts needing a concentric hole. Usually I will be boring after for size and concentricity.

I use chuck and drill, or taper shank drill. chuck is probably screw thread, either type works, I thin the little one is thread, the larger is taper.

For any mediumto large hole I put on a dog and rest it on compound or a 'drilling bar".... to prevent spinning.

tdmidget
01-02-2011, 08:59 PM
I'd like to be able to drill in the lathe.

I have seen some Jacobs-style chucks having tapers and others having threads. Does it matter which style I get? The other end will be MT2 to fit in the tailstock.

How often do you put the chuck in the headstock and use a fixture to hold the work?

Or, is this all obsolete and everyone just uses a drill press or mill?

Does it matter? Only if you want to make a decent part. Jacobs lists some the threaded junk as being allowed .015 run out. Get a real chuck and the proper arbor for it. The threaded crap will break drills and make oversized holes.

tdmidget
01-02-2011, 09:04 PM
I'd like to be able to drill in the lathe.

I have seen some Jacobs-style chucks having tapers and others having threads. Does it matter which style I get? The other end will be MT2 to fit in the tailstock.

How often do you put the chuck in the headstock and use a fixture to hold the work?

Or, is this all obsolete and everyone just uses a drill press or mill?

Does it matter? Only if you want to make a decent part. Jacobs lists some the threaded junk as being allowed .015 run out. Get a real chuck and the proper arbor for it. The threaded crap will break drills and make oversized holes.
PS I checked and they no longer show a run out. Since they are now made in China it's probably worse. Get yourself a Rohm if you are on a budget

J Tiers
01-02-2011, 09:12 PM
Does it matter? Only if you want to make a decent part. Jacobs lists some the threaded junk as being allowed .015 run out. Get a real chuck and the proper arbor for it. The threaded crap will break drills and make oversized holes.

Not if you buy something that was NOT made to go on a homeowner drill.

A good threaded-mount chuck, with a good arbor, will be as concentric and work as well as a taper-mount type.

Mine is just about dead-on concentric. But it wasn't cheap, and neither was the arbor. it's a 32-BA, IIRC. Available in either taper or threaded.

Tony Ennis
01-02-2011, 09:18 PM
Get yourself a Rohm if you are on a budget

Funny you should mention that. In the toolbox of mystery tapers, I found a Rohm 1/2" chuck.

R3-2 ROHM 1/32 - /2 T.2 KEY S-10 W GERMANY

It's got a taper of some sort. I think some research is called for.

PixMan
01-02-2011, 09:34 PM
Not if you buy something that was NOT made to go on a homeowner drill.

A good threaded-mount chuck, with a good arbor, will be as concentric and work as well as a taper-mount type.

Mine is just about dead-on concentric. But it wasn't cheap, and neither was the arbor. it's a 32-BA, IIRC. Available in either taper or threaded.

I don't know about that. While I admit I've never used a thread mount chuck on a Morse Taper adapter, I've never seen one run quite are concentric/true as a QUALITY double-tapered type.

OTOH, I have seen some double taper arbors be junk. Dad's Enco drill press came with an apparently butter-soft one between the spindle and the 5/8" capacity chuck. It actually bent when a 1/2" drill caught.

I replaced it with a genuine Jacobs MT3-JT33 arbor, and WOW, what a difference. The chuck now runs dead true, something it never really did as new.

Tony Ennis
01-02-2011, 09:39 PM
Heh, the specs stamped on the chuck don't match the specs for the current R3-2 model (WTF! lol) Thus I can't trust the current taper spec, either.

I sent an email to Rohm.

gnm109
01-02-2011, 10:33 PM
I drill holes routinely with my 13 X 40 Enco. When I bought the lathe, I also got an MT3 to JT6 adapter for the tailstock. I got a 1/8 to 5/8 keyless chuck and it works very well. The MT3 end has a tang that locks into the tailstock. If I want a really good hole, I will drill undersize and then ream or bore.

Works for me.

J Tiers
01-02-2011, 10:37 PM
I don't know about that. While I admit I've never used a thread mount chuck on a Morse Taper adapter, I've never seen one run quite are concentric/true as a QUALITY double-tapered type.


No doubt true..... although the differences will be small enough that there is no danger of breaking drills due to off-center.

A taper can be ground to tenths or better, and it ends up with zero clearance if "perfect".

A thread can be ground to a "very good" standard, but at the end of the argument one is left with "some" clearance that is required to screw it in... The thread itself is somewhat self-centering, since it is essentially a cone wrapped around a cylinder..... But friction, etc, make it unlikely to get much better than 0.001 or so.

That still is not enough to break many drills, or cause drastic wrong-sizing that is beyond what you have a right to expect from drills to begin with, nemmind the chuck.

tmc_31
01-02-2011, 11:12 PM
I drill holes routinely with my 13 X 40 Enco. When I bought the lathe, I also got an MT3 to JT6 adapter for the tailstock. I got a 1/8 to 5/8 keyless chuck and it works very well. The MT3 end has a tang that locks into the tailstock. If I want a really good hole, I will drill undersize and then ream or bore.

Works for me.

gnm109,

What is the largest drill that you have used in your tailstock? Have you ever used a drill in your tailstock under power by tying the tailstock to the carriage? If so, what is the largest drill you have used in this fashion? I also have a 13X40 lathe and will be trying this with a 7/8" drill in A36. Software shows to run the feed at .0028ipr. I also have a tool holder for a mt3 shank drill for my QCTP coming.

Jim Shaper
01-03-2011, 12:11 AM
I've done 1" numerous times via the tailstock taper with an 18N jacobs using silver & demming shank drills. I pilot them to 1/2" first, simply due to the point/flute clearance on a 1" twist drill (it also allows me to get some oil in there).

It's popped the arbor loose a time or three, but nothing another whack with the dead blow doesn't correct.

gnm109
01-03-2011, 12:21 AM
gnm109,

What is the largest drill that you have used in your tailstock? Have you ever used a drill in your tailstock under power by tying the tailstock to the carriage? If so, what is the largest drill you have used in this fashion? I also have a 13X40 lathe and will be trying this with a 7/8" drill in A36. Software shows to run the feed at .0028ipr. I also have a tool holder for a mt3 shank drill for my QCTP coming.


On my Enco I've not tied the tailstock to the carriage, at least yet. I'd have to find some way to do that. In any case, too much pressure would probably shear the 2mm aluminum shear pin on the acme screw that drives the carriage.

I've drilled up to 1" holes in aluminum and steel round stock and also in thick square steel and aluminum plates that were in the 4 jaw chuck. I run slow at 70 rpm on a 1" drill but it works very well. I simply turn the crank on the tailstock to drill the hole. I've got several Silver and Demming style drills with half inch shanks.

I don't see any advantage at all to power drilling with your lathe. I much prefer feeling the drill in by hand. It also helps sometimes to be able to peck and also quickly remove the drill to clear the chips out. I also use plenty of lube....

If there is too much pressure, you will probably shear something, at least it would on my machine. I also learned to do cutoffs by hand, rather than using the power crossfeed. Cutoffs seem to want to be felt out so that you don't break a tool.

.

dp
01-03-2011, 12:39 AM
I bought a Jacobs No. 14 chuck on Ebay years ago for about $15 or so. Replaced the old taper with a new one, took the chuck apart and cleaned it up inside and out. Touched up the jaws lightly - didn't require much, deburring, mostly, and it's been a solid chuck for me.

http://metalworkingathome.com/images/JacobsNo14.jpg

Looks like I need to get some rust proofing out. Such is the fate of bare steel in Seattle :)

Black Forest
01-03-2011, 01:42 AM
I recently broke my Albrecht 1 - 13mm drill chuck taper. The drill caught in the work and snapped the taper and drill bit.

I called Albrecht and talked to the service man. What I have is a double taper arbor. It is a MT2 to a what they call a cone. I thought I had an integrated MT2 taper. Meaning the taper and the body is one piece. After much back and forth and wrong parts I finally have my chuck back together. I rebuilt it with a integrated taper by replacing the chuck body with the one with the integrated taper. The reason being Albrecht told me they were more accurate.

The Albrecht drill chuck is very interesting in how it is built.

tmc_31
01-03-2011, 02:19 AM
Thanks guys,

I plan on experimenting with the power drilling thing and power tapping when I get my tools in (hopefully on Tuesday). I will report the results for anybody interested.

I will report on a new thread so as not to hijack this thread any further, my apologies to Tony.

Tim

PixMan
01-03-2011, 06:46 AM
gnm109,

What is the largest drill that you have used in your tailstock? Have you ever used a drill in your tailstock under power by tying the tailstock to the carriage? If so, what is the largest drill you have used in this fashion? I also have a 13X40 lathe and will be trying this with a 7/8" drill in A36. Software shows to run the feed at .0028ipr. I also have a tool holder for a mt3 shank drill for my QCTP coming.


Just out of curiosity, what software would have a 7/8" drill at that low of a feed rate? I have a pretty good (if free) program that would suggest almost 4 times that feed rate, and that's without a pilot hole. I also know from experience that a feed rate that low is practically rubbing the drill to dull even WITH a pilot drill. The A36 material is pretty easy-cutting, so push it.

This screen shot shows some data. You can't really use it at those numbers because you don't have the required torque or HP on your machine, but you can see where the drill is capable of running. If you were to pilot with a 1/2" drill, I'd venture that HP requirements of the 7/8" drill would be 1/3rd or less than shown even with a similar feed rate. It'll be lower because most of the power used is, as you know, at the center of the drill.

http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/Clip-1.jpg

I didn't have much luck using a drill in the QCTP. In my case, it was a 1-1/2" insert drill in a CA/400-size No.4 heavy duty boring bar block. The pressure at the tip of the drill, sticking out out by about 4-1/2", was pushing the QCTP out of square. (Rotating it about its bolt-down axis.)

In my younger days I used to drill a LOT of 2" to 4-1/2" holes in 1020 HRS in a manual lathe. We used big spade drills, and had the drills in the MT5 tailstock of the 27 x 60 Polish lathe. We had fashioned a hook-up between the cross slide and the talstock to have the carriage feed pull the tailstock. It worked great because all the force was straight in on center.

Best of luck.