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I'm having a tough time keeping my MT2 Drill Chuck secured in the Tail Stock, I have to have a death grip on the chuck and the Tail Stock with my left hand when I retract the bit or the chuck gets loose.
Does anyone here use or have comment on a Drill Chuck with a draw bar? Are these made?
Thanks,
Tim
My drill chuck has a 1/4 x 20 thread for a drawbar. I think that is fairly common. But, i am not sure it will work in the tailstock because the distance between the chuck and the handwheel increases as you drill, Have you checked your MT taper and the seat in the tail stock for nicks or dirt. Mine locks up pretty easily. I still have to hold it for a large forstner bit, but a death grip is not required.
I only drill about an inch at a time, withdrawing the bit to clean it and allow it to cool down. Also drill at 500 rpm to keep the heat down. Fast rpms and deep drilling make for wood expansion.
When I insert my chuck with adapter into the tailpiece I give it a tap with a hammer. I use some scrap hardwood between the two but that seams to seat it just fine. If yours isn't and you don't see anything like what Paul was talking about then I would suspect that one or the other might be slightly machined incorrectly.
It sounds like at some time in the past the Morse taper shank on the drill chuck has spun while in the Morse taper socket of the tailstock quill. This will cause galling on both surfaces and prevent solid contact in the future. Look at the shank of the drill chuck to see if it has rings with raised burs and dig ins. Use a flashlight to examine the socket on the tailstock. It should be smooth and shiny. If it has damaged areas like the shank has that is a problem that needs to be repaired. Morse tapers hold because the two surfaces are high precision machined to enable metal to metal bonding by molecular level forces. When either of these surfaces becomes damaged usually by spinning this is no longer possible. The MT socket is easy to repair using a Morse Taper hand reamer. Repairing the MT shank on the drill chuck is more difficult, but it is much easier less costly to just replace the shank on the drill chuck. The taper on the drill chuck is usually a Jacobs taper #6, but sometimes it is a #33. For about $10 you can get a MT2 to JT6 shank.Quote:
Originally Posted by Tim Boger
Once the MT socket on the tailstock has been repaired never insert a damaged MT shank into it or else the damaged shank will just cause the socket to become damaged again. If any of your MT shanks have light rust they should be cleaned up with 150 grit silicon carbide sandpaper and polished using a metal polish. If you live in a humid area where things rust it would be a good idea to use WD4 to protect the shanks, but be sure to clean the WD40 from the shank using naphtha or some other solvent before using it. Otherwise the oil could cause the shank to slip in the socket.
Try retracting the jaws all the way in and firmly seating the chuck with a hammer & block of wood. Do you have another MT2 taper? Does it seat well?
Tim,
Sometimes my drill chuck tries to spin. But if it does, I withdraw, clean it and reseat. I don't let it spin as it can mess up the MT. Also, a sharp forstner is less likely to spin.
When I withdraw the forstner from a drilled pocket that is when it is more likely to pull out and spin. That is when I need to hold on tight. But blowing out the chips frequently really minimizes that.
Thank you Paul
Thank you Dwight
Thank you Alex
Thank you Bill
Thank you Bruce
Tim,
The problems I see with using a drawbar in the wood lathe tailstock are the change in length as you crank, and also the hole through most tailstocks
Is your chuck keyless or keyed? I have several keyless and one precision keyed chuck with 2MT mandrels. The keyed chuck has three holes near the front that can be used with a tommy bar to keep the chuck from turning. I don't recommend using it held in the hand like this but rest the bar on the tool rest.
Attachment 410308
The keyless chucks also have such holes but they are on the part of the chuck that turns to tighten. I haven't tried holding them with a bar. My keyless chucks have a knurled flange near the 2MT mandrel which I have held with my left hand - it would be simple to drill some holes in it for a bar or pin wrench. What I have done when drilling large holes with the keyless chuck is grab and hold this flange with large pliers.
If your work is in a chuck (typical), you can use a drawbar if you put the drill chuck in the headstock instead of the tailstock. Mount the scroll chuck holding the work on the tailstock with a 2mt to spindle thread adapter.. probably easier than holding onto the I make drawbars from allthread rod. I grind a flat near the back end to grip with an adjustable wrench to remove if needed.
Attachment 410305
I use this adapter in the tailstock for positioning things but it should be OK for drilling if you hold on to the work - probably easier than holding onto the chuck! If the work is a spindle square blank I have held it with an adjustable wrench.
But all this said, I've almost quit using drill chucks to drill on the lathe and have switched to taper shank bits if I have the right size. I bought a bunch from Wholesale Tool Co. for as little as $1 each for the smaller sizes. A taper shank bit will fit into the 2MT socket of the tailstock directly or with an adapter for the smaller sizes.
Attachment 410306
An advantage to the taper shank bits is you don't need the chuck with the extra length and potential decrease in precision alignment or stiffness. Look at the length difference between the drill chuck and taper shank bits, both the same diameter (the shadow seems to show one bigger):
Attachment 410307
I always grip the taper shank bit with vise grip pliers while drilling to prevent it from spinning. I rest the handle of the vice grip on the tool rest while drilling.
As Bill mentioned, spinning a mandrel in the taper even once can be bad - it can gall the metal on the chuck (which can be cleaned up with a flat file) and worse, gall the metal inside the 2MT socket. A 2MT damaged like this won't hold anything. The socket can sometimes be fixed with careful work with a round file, but better, a 2MT reamer. I bought this a few months ago to repair the tailstock socket on my metal-cutting lathe after a bit spun while drilling steel.
https://www.amazon.com/gp/product/B07933VYD7
JKJ
Quote:
Originally Posted by Tim Boger