Holding morse taper bits in a chuck

[John Rumm]

So a mate turns up with a lump of steel about a foot square and not far short of an inch thick. Says he wants a 4 inch strip cut off the side, and then a 3/4" hole drilled through one end of the bit we cut off.

So, ten to fifteen mins with the 9" grinder later, and we had a big pile of grinding dust, and a lump of metal (not sure what kind of steel it was). So I made a 1/4" pilot hole, and then stepped up until I have it at 1/2". Then realised that I did not actually have any HSS bits in large enough sizes. A bit of a rummage later and I found some blacksmith drills that came with an ancient small lathe that I was given, including something close enough to the size required.

Only problem was the drills in question had morse taper shanks, and the taper on my bench drill is both the wrong size, and the wrong way round (i.e. the shaft is part of the quill and the socket in the chuck) so I could not mount the drill directly. So in the end I had to go for a bodge, and grip the shank of the drill as best I could in the three jaw chuck, get it roughly centred, and then rely on the pilot hole in the material to keep it inline. Splashed on some cutting fluid, and took it slow (the drill has not really got the oomph for that size in steel, and the belts slip if you push it too hard). Got the job done in the end.

Which made me wonder, is there a nifty trick for holding MT shank drills when all you have is a jacobs style chuck?

[mailbin]

An R8-MT adapter should do it

[mailbin]

Alternatively, and if your chuck is big enough, you could use a "solid morse taper socket". Perhaps you could reduce the extension by getting a soft solid MT socket and boring a tapered hole in the back to match your drill quill taper so you could dispense with the chuck

[John Rumm]

Not sure from memory of its 13 or 16mm maximum.

Yup that could work, although would test both my machining skills, and my geriatric lathe!

[mailbin]

In that case why not find a bit of mild steel bar that's larger than the MT you want, step bore it close to the MT that you want and then finish with an MT reamer. Mount an MT stub in the lathe (or turn one, it's not difficult), fit your new female MT over the stub and turn the opposite end down to a size that will fit in your chuck. It should be concentric enough for drilling and there's nothing tricky involved. If you made it as MT3 you could use sleeves to adapt it to MT2 and MT1 if neeed.

Alternatively, take an MT sleeve with a reasonable hole (preferably soft, but you can probably soften a regular one), mount it on an MT stub in the lathe (preferably turned in situ, as above) and tap the inside of the hole. Then get a bar that will fit in the chuck and thread the end to fit the hole you've just tapped in the sleeve. You should probably arrange for the bar to have a shoulder for the sleeve to tighten against.

I would go for the first option because it's going to be more accurate and I don't like threading.

[FMurtz]

Turn the drill shank parallel.

[Tim Lamb]

Not likely to help you but I have heard of lathes being used as a drill press.

>

[John Rumm]

Yup that would work - so long as I don't want to go back in the tail stock directly.

[John Rumm]

My lathe is similar to:

can't see that swinging a 12" lump of steel!

[Tim Lamb]

I think you fit the drill in the headstock and use the tailstock adjustment to provide the drilling effort.

Fortunately my pillar drill has a no 2 morse taper quill...

[John Rumm]

I was about to say I don't think my headstock has a taper (its an externally threaded nipple) however you have made me wonder enough go go take the chuck off and have a look to see if it has an "inside" ;-)

I think when I build a bigger workshop, a decent floor standing drill would be a good addition.

[John Rumm]

Well you learn something every day ;-) It does indeed have a taper on the inside of the headstock - only a 1 or 2MT by the looks of it, but some of my drill do indeed fit it.

[Tim Lamb]

Yes. Ideally one where the table height can be easily altered and swung out of the way for special jobs.

Mine cost ?2.50 but that is a long story:-)

[Tim Lamb]

Now you will have to re-centre your chuck:-(

My pillar drill has a slot in the quill where you insert a wedge to tap out the drill/chuck. Presumably you can shove a rod through your lathe spindle to release any taper shank drills.

[John Rumm]

For the quality of work done on this machine, screwing it back on its mount has done that with enough accuracy ;-)

Yup looks like it.