Collets

[Ian L2Participant @ianl2]

I am not far off getting Halifax 10" (Atlas) lathe running. Looking to purchase some collets to fit milling cutters in place of the chuck. Do all MT collets fit I'v seen quite a lot but none mention the Halifax or Atlas l0" lathes. Some seem to have something that screws on the threads that hold the chuck, is this thread the same on all machines?

[Ian L2Participant @ianl2]

confused what should I purchase

[Enough!Participant @enough]

Morses for courses – if it's designed for a certain size of MT collet, any MT collet of that size should fit. It's a standard.

[Thor 🇳🇴Participant @thor]

Hi Ian,

The thread that holds the chuck differ from one lathe to another. The Myford ML7 uses 1 1/8 x 12 TPI (with MT 2 in the spindle), the 10" Atlas seem to have 1.5" x 8 TPI NF (with MT 3). You can get MT 3 collets that should fit the 10" Halifax.

Thor

[Bob Brown 1Participant @bobbrown1]

I found that the collet chucks that fit on a back plate are the most versatile as it allows bar to pass through the head stock.

[Ian L2Participant @ianl2]

Thanks Guys

Thor. In the link in your posting the collets mention Draw bar thread XXmm do I need to purchase something to pull and hold these in the lathe also how does one get them out?

Bob. not seen any that fit on a back plate but will have search on internet latter.

[Bob Brown 1Participant @bobbrown1]

here you go **LINK** amongst others

Bob

[Ian L2Participant @ianl2]

Thanks Bob

[RobboParticipant @robbo]

Ian,

Further to Bob's post ,collet chucks that fit on a backplate can also be more accurate than those with a built in thread.

The accuracy depends on the chuck having a snug fit on the spindle register, the thread serves to draw the chuck onto this. With a ready made threaded chuck the register may not be the required fit. However, as the backplate will be machined on the lathe itself to fit the back of the collet chuck, concentricity should be guaranteed.

However, if you just want to try it out, get MT3 collets to suit the size of your milling cutters and make yourself a drawbar to pull them in to the taper.    Cheapest option while you decide if you need ER collets, and if so which size.

Edited By Robbo on 26/12/2014 10:34:40

[Ian L2Participant @ianl2]

Posted by Robbo on 26/12/2014 10:13:13:

Ian,

Further to Bob's post ,collet chucks that fit on a backplate can also be more accurate than those with a built in thread.

The accuracy depends on the chuck having a snug fit on the spindle register, the thread serves to draw the chuck onto this. With a ready made threaded chuck the register may not be the required fit. However, as the backplate will be machined on the lathe itself to fit the back of the collet chuck, concentricity should be guaranteed.

However, if you just want to try it out, get MT3 collets to suit the size of your milling cutters and make yourself a drawbar to pull them in to the taper. Cheapest option while you decide if you need ER collets, and if so which size.

Edited By Robbo on 26/12/2014 10:34:40

Hi Robbo

Just bit confused with what you mean with back plate machined on lathe itself !

[John HaineParticipant @johnhaine32865]

When it comes to the drawbar, the easiest thing to do is buy a length of studding the right thread for your collets and saw off a suitable length. Use either a big washer or if you want to be fancy make a bush to locate the other end of the studding for the nut to tighten against. You do NOT want a very high tightening force on a morse taper, it just gets stuck! No need for high tensile steel drawbars or anything like that.

[Bob Brown 1Participant @bobbrown1]

Posted by Ian L2 on 26/12/2014 10:58:55:

Hi Robbo

Just bit confused with what you mean with back plate machined on lathe itself !

With any back plate it is normal to fit the bare back plate the spindle and machine the chuck mounting face while attached including any register (step) to locate the chuck on the back concentric to the lathe spindle and square.

**LINK**

[Ian L2Participant @ianl2]

Posted by Bob Brown 1 on 26/12/2014 12:43:47:

Posted by Ian L2 on 26/12/2014 10:58:55:

Hi Robbo

Just bit confused with what you mean with back plate machined on lathe itself !

With any back plate it is normal to fit the bare back plate the spindle and machine the chuck mounting face while attached including any register (step) to locate the chuck on the back concentric to the lathe spindle and square.

**LINK**

So what I need is a back plate to match the spindle thread on my lathe.

[OuBallieParticipant @ouballie]

I just knew I would be kicking myself soon after finishing the Marlow Drawbar

Completely forgot about them collects I have

A solution can blithering well wait until I need to use one

Other half's voice just about gone due to yakking the past two days with family and friends and too much

Geoff – Peace and quiet for a while now

[Author]

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