How To Mount A Drill Chuck?

hello folks

Peter here, brand new to machining and the forum so please forgive the newbie question, but I know the expertise I need counsel from will be here

I have just got my first lathe, but the work I want to create is very small - I am working on a 1/18 scale Supermarine Spitfire and things are generally tiny..

The stock I want to machine is mainly between 1 to 8mm in diameter so the 3 jaw chuck is too big to hold it. I bought a precision drill chuck with it that is supposed to go in the tailstock I think

My question is whether there is any way to mount this in the headstock? Can I remove the 3 jaw chuck and replace it with this? I have an arbor on it that seems to slot in the 3 jaw chuck, (and there seems to be a hole right through to the gearbox) but it is not stable or central

Or is there another way to hold work that is smaller than the closed 3 jaw chuck?

any ideas or suggestions?

yours in hope

Peter

If available , collets .

airscale said:

hello folks

Peter here, brand new to machining and the forum so please forgive the newbie question, but I know the expertise I need counsel from will be here

I have just got my first lathe, but the work I want to create is very small - I am working on a 1/18 scale Supermarine Spitfire and things are generally tiny..

The stock I want to machine is mainly between 1 to 8mm in diameter so the 3 jaw chuck is too big to hold it. I bought a precision drill chuck with it that is supposed to go in the tailstock I think

My question is whether there is any way to mount this in the headstock? Can I remove the 3 jaw chuck and replace it with this? I have an arbor on it that seems to slot in the 3 jaw chuck, (and there seems to be a hole right through to the gearbox) but it is not stable or central

Or is there another way to hold work that is smaller than the closed 3 jaw chuck?

any ideas or suggestions?

yours in hope

Peter

Click to expand...

You can get Morse taper adapter to go from one size to another. You can also get inexpensive Morse taper to Jacobs taper adapters. Morse tapers used in the headstock without a force pushing or pulling in can work loose during use with potentially disastrous results.

A collet system would be a better way to go, although more expensive, due to the need for a set of collets. A typical way to go would be to buy or make a backing plate to mount instead of your 3 jaw and machine it to fit the collet chuck. This results in closer mounting to the spindle, important to control flexing, and typically less runout.

You would probably opt for an ER style collet. An ER20 will accommodate work from 1mm to 13mm. An ER25, from 1mm to 16mm, and an ER32 from 1.5 to 20mm.

Tormach offers collet chucks for their TTS system which have a 3/4" shank which could be mounted in your 3 jaw or 4 jaw chuck. The TTS chuck is around $30. It's not ideal but would get you started.

Collet chucks are generally available on line. Look on line for less expensive collets.

I agree that collets would be the way to go - a drill chuck is just too inaccurate for the work you want to do. All lathes have an internal taper in the spindle and typically there will be a collet to match that taper, usually a Morse taper. You can simply make a drawbar that screws into the back of the collet and as you tighten it, it will lock the part and be as accurate as your spindle. Sherline does exactly this and it is very, very accurate.

ER collets for sure. And at the scale you're working the smaller, cheaper ER20 would be ample. (The number indicates maximum capacity in millimeters.) And unlike most other collet systems it closes at the front, so you can have a collet block (google it) mounted in a mill vise, for instance, and you don't have to remove the collet block from the vise in order to remove the part from the collet and insert another. It's a very cool system.

What lathe do you have?

Thank you gentlemen, very much for your advice

I was hoping I could aviod the expense of collets, but then if it was as easy as I thought to just use a drill chuck then everybody would be doing it I suppose

Sounds like ER20 collets are the answer, and I have found some at the same online store I got the Lathe from - (Axminster C2/300 Mini Lathe Sieg C2A). I will need to get a holder too

Is the idea that an arbor is a friction fit into the chuck, or do you tighten the jaws onto it? The arbor I have (MT3 B16) seems to fit into the hole, but it does not lock solidly and centrally like the pointed centering part that fits into the tailstock. The collet holder I looked at that goes with the ER20 Collets says MT2 which is the same as another Arbor I have, but that is too small for the headstock

I am sorry to ask what must seem ridiculously stupid questions - I have so much to learn and this is literally day one A, B C stage for me

Thank you again for your patience

Peter

You're in the right place for beginner questions. Every member here remembers being a beginner, and a lot of us still are. You may occasionally catch someone here on a slightly more grumpy day than another, but there doesn't seem to be anyone here who looks down on another member for wanting to learn something others have already mastered. Crazy, right?

I don't have many answers beyond the collet recommendation myself, as I'm not all that much further along than you have. As I mentioned in another thread yesterday I have tons of time to read, but very little time to practice, so I'm just regurgitating what I've read.

Sorry, I forgot to actually answer this part:

A Morse taper is designed to be a friction fit, no tightening/drawing needed. I wasn't familiar with that model, but I looked it up and sure enough it has an MT3 headstock and MT2 tailstock. The good news is those are both very common sizes for all sorts of accessories. The bad news is they aren't the same. I have seen MT2 to MT3 adapters (and many other taper-to-taper adapters) but every time you introduce something like that you are adding another potential point of failure/flex/inaccuracy.

Some milling machines were/are equipped with Morse taper spindles. A lot of drill presses also have MT spindles. Drill presses generally do not have drawbars, only a friction fit of the tapers. Milling machines with MT spindles have been built with and without drawbars. In a drill press there is minimal side loading, and tapers usually stay put. Milling machines have heavy side loading, and sometimes on the old machines without a drawbar the taper would come loose, usually damaging the work, the tool, the spindle, or all of them. On a lathe, much work is concentric with the spindle, like drilling and reaming on the center line. Turning, facing, and milling on a lathe is a whole different type of loading, and the tapers may come loose without a drawbar to keep them in.

Here is a pic of a couple vintage NOS Putnam MT3 end mills, one 7/8" and the other 1", probably at least 50 years old, they look like they were made last week. I only kept them because I thought I might sometime want to put them in the tailstock of my lathe for finishing holes with a square bottom or shoulder. I also have an adapter to fit them in my R8 mill spindle, but I don't think I have guts enough to try that, even though that was what they were designed for...

Interesting. I had read that Morse tapers were designed to not be drawn. Good to know.