Flexispeed Lathe

I have just bought a 60s Flexispeed Meteor 2 lathe. It's in excellent condition having been owned by an engineer.

The problem I have is I don't have a 3 jaw chuck for it . It has a very nice Burnerd 65mm 4 jaw chuck , a faceplate and tailstock chuck.

I need to find a chuck to fit the 1/2" BSF spindle or can I find someone to modify a modern 65mm 14x1 modern 3 jaw chuck ?

I did read an article here from 2015 where a person named Roderick turned a bush with the correct internal thread , and pressed it into a modern chuck.

Is this person still able to do this, or is there anyone else who could ?

I would be most grateful for any help, and of course happy to pay for such a job

Regards

Rob

Have you tried to match the MT0 spindle taper to a chuck?

I haven't, but I am not sure I like the idea, and there might be a bit much overhang.

I will give it some thought. Cheers Dave.

Rob

It actually depends on what you want to make with the lathe,.....Several members of my clock club have Flexi's and at least one uses ER 16(?) collets in a collet chuck using a drawbar in the spindle throat.

Also, if you have a good 4 jaw then you hardly need to bother with a 3 jaw....It does take an hour or so to get the hang of centreing work using a dial guage but there after it's very easy and gives the best accuracy of any workholding method.

Finally, be extremely careful about always measuring and checking threads on your machine (especially chuck fit) since there were several used during the production life of th Flexi and this is perhas one of the biggest drawbacks to using a Flexi now.

Thank you your comments. I do have good 4 jaw, and dial gauge. I will give it a try when I have the lathe set up.

At the moment I am sorting out drive belts.

Looking at what I can find on the history of Flexispeed lathes. I think this one is early to mid 60s. No later than that I reckon.

I understand what you say re the threads, and am cautious of that.

Your comments are much apprieciated.

Rob..

Thank you your comments. I do have good 4 jaw, and dial gauge. I will give it a try when I have the lathe set up.

At the moment I am sorting out drive belts.

Looking at what I can find on the history of Flexispeed lathes. I think this one is early to mid 60s. No later than that I reckon.

I understand what you say re the threads, and am cautious of that.

Your comments are much apprieciated.

Rob..

you ?

Bob makes an excellent point: if I could only have one chuck, it would be a 4-jaw. There are turners who, by choice, always use 4-jaw chucks.

The advantage of a 3-jaw chuck is speed. They are the quickest easiest way of gripping round work and hexagons, but after that are nothing but bad news. They're not very accurate in terms of run-out, which often doesn't matter, and it's difficult to reset work in them, which does matter. So 3-jaws are great for turning shortish round jobs, where it's not necessary to move the work half-way through to a mill, saw, shaper or bench vice, and then go back to the lathe. Perhaps 90% of what I do can be done in a 3-jaw.

Collets have low run-out, are good for close work, and support fast accurate resetting but can only hold round objects of particular diameters. Extremely useful for certain types of work, such as clockmaking, but otherwise limiting.

4-jaws chucks are versatile. They can be adjusted to minimise run-out, accurately reset, hold shapes other than round, and offset jobs for boring super-accurate holes. Offsetting is also useful for turning ovals. The downside is having to learn how to use them. Centring 4-jaws is best done with two chuck keys and a DTI :

1. Using one chuck key, position the job centrally by eye, but don't tighten the jaws.
2. Position the DTI to measure how far the job moves horizontally when the chuck is turned.
3. Turn the chuck by hand so one pair of jaws are horizontal. Note the DTI reading. Turn the chuck through half a turn. If the job is centred, first DTI reading minus second DTI reading = zero. If not zero, use both chuck keys on the opposing horizontal adjusters to ease the job such that the DTI difference is halved. Repeat step 3, halving the difference each time until the DTI says the job is centred. Then go to step 4
4. Turn the chuck through 90° and repeat step 3 on the other pair of jaws.
5. When the job is centred between both pairs of jaws, carefully tighten them without moving the work. Confirm with the DTI.

At first adjusting a 4-jaw is tedious and fiddly, especially if attempted with only one chuck key. Don't give up! The good news is the technique gets faster and easier with practice. An experienced operator can often get close enough by eye with a few tweaks, for example by looking for wobble relative to the sharp end of a centre held in the tailstock. Lesser mortals, and those needing high accuracy should confirm all is well with the DTI. The accuracy of the method is limited by the sensitivity of the DTI as a comparator and even a cheapo one should centre within 0.01mm.

Dave

Cheers Dave ,

I certainly will try to get to grips with the 4 jaw, but in reality I don't need that sort of accuracy for the work that I do. I know of course there are times I could need the 4 jaw, and I certainly use it then.

Re the Flexispeed threads.. I am a bit puzzled by the measurements I have taken. The spindle nose is said to be 1/2" x 16 tpi BSF, but my measurements are imperial 0.545" thread diameter and 0.550 register. Metric are 13.87 thread 13.97 register. Can anyone make sense of that ?

It seems more like it might be M14x1 than BSF

Yours Puzzled

Rob

Cowells lathe is m14*1, I think unimat is same, perhaps someone can confirm 

Edited By duncan webster on 12/10/2021 13:48:06

That certainly sounds like M14 but you should check the pitch. Early Cowells lathes were M14x1.5 not 1.0

Here is the drawing of the early spindle : **LINK**

https://www.model-engineer.co.uk/sites/7/images/member_albums/79913/669092.jpg

MichaelG.

I have a knackered Unimat chuck it is 14mm but the thread looks very fine. I also have what is I think a 1/2" BSF arbour . it will screw in to the $ jaw chuck that fits the lathe spindle. it's a very sloppy fit. So obviously not right. The thread pitch looks similar, but is not exactly the same. Quite course though. Nothing like the Unimat thread. Would it be any use me phoning speaking to somebody at Cowells ?

The drawing for the spindle is useful, but my spindle is not quite same. Mine is not bored right the way through for instance. On my previous Flexispeed it was.

It is quite mystifying at this stage, but as an engineer I worked with years ago said to me. ' There is not an engineering problem that can't be solved'.

Rob

Edited By Robert Holton on 12/10/2021 15:11:22

Robert, where are you? My Cowells is an early, so it has M14 * 1.5 thread. If you're nearby you can borrow a chuck to try, or even bring the lathe round, but these chucks are as rare as the proverbial rocking horse droppings, so I'm not keen on trusting to the post. I'm in North Cheshire

The Unimat 3 is M14 x 1 and IIRC the thread and register OD are just as you measured. I may have the odd threaded collar I could let you have to try?

Unimat 3 and 4 are 14x1

Dave

Just put a mm steel rule against the nose. You should easily be able to see if the pitch is 1.0.

Hi All, I checked the internal thread on an old Unimat chuck and it is very fine. I have since removed the chuck from the Unimat I use and checked. It is indeed a very fine thread not like the thread on the Flexispeed. Is it possible there is a coarse metric thread it could be ???? I will check it with a m6 screw.

Duncan, I live in Madeley, Shropshire, near to Ironbridge, so a bit of a distance really..

Thank you everyone for all your help so far, but the mystery isn't solved yet ......

Rob.

Hi All, I checked the internal thread on an old Unimat chuck and it is very fine. I have since removed the chuck from the Unimat I use and checked. It is indeed a very fine thread not like the thread on the Flexispeed. Is it possible there is a coarse metric thread it could be ???? I will check it with a m6 screw.

Duncan, I live in Madeley, Shropshire, near to Ironbridge, so a bit of a distance really..

Thank you everyone for all your help so far, but the mystery isn't solved yet ......

Rob.

As a matter of interest, I have just checked the Unimat thread with a 6mm  screw and the pitch matches perfectly.

Now I will have to go through the bolts and set screws and compare with the Flexispeed thread.

Edited By Robert Holton on 12/10/2021 19:34:35