Running a 125mm chuck in a Myford ML10 SPEED 10

Think of getting a new chuck for speed 10

but rather than just go for standard 100mm 4”

thought May go for 125mm 5” as would give me options

for the future , but are there any disadvantages or even advantages.

Any advice appreciated

Thanks

I'm hiding under the rug, ready for the barrage.

Steve.

Please read previous threads.

:O)

Martin

I might have to join you

If you fit something large in that chuck the jaws might hit the bed!

YOu could do a Burt Munro and cut a section out of your bed with a hacksaw. I suppose in today's world an angle grinder would be more appropriate. ( )

Edited By Hopper on 15/11/2020 23:41:53

👏Thanks , I’ve just checked with the 100mm chuck with jaws fully extended leaves me 12.3mm clearance but i running a 125mm chuck I would need 12.7mm and prob 13mm at least so unless I make my own gap to be on the safe side I’ll think I’ll stick with 100mm 👍

Sorry rik. There was a thread the other day with the same question nearly. Many said a 125mm chuck on the Myford would not do the bearings much good. I have a 125mm 4 jaw & use it often. On the Super 7B. But that has a bronze front bearing & twin races at the rear. . I think you may have white metal bearings which are considered to be fine with a 100mm but not with a 125mm. Only a reply from others. I do not know the answer.

Steve.

Apology not needed I have speed 10 with later taper bearings , but now after measuring clearance with the jaws fully opened wouldn’t clear the bed IF I wanted to turn something at the max the 5” jaw could take but would probably be very rare if at all , so would be interested if anyone running a 5” on a ML10 or Speed 10 or Diamond etc . 👍

Bearing load and other stresses increase more than common sense might suggest because the weight of a chuck is proportional to the square of it's radius. A 50mm x 125mm chuck is roughly twice the weight of a 40mm x 100mm chuck, not 25% heavier. And because bigger chucks will used to support heftier work as well, the total stresses could be out of specification.

As even grossly overloaded machines are unlikely to fail immediately, such 'upgrades' often seem harmless. It takes time for damage to become apparent, thus a bearing that would have lasted 20 years, now only lasts 2.

Bodgers rarely think about long term consequences, so in their world this isn't a problem. Think twice about buying a second-hand machine the owner has 'improved' with this sort of modification. Self confidence is not valid engineering, ask to see his sums and references!

But hobby lathes generally have an easy life. They aren't worked flat out round the clock like production kit. So while I wouldn't fit an oversized chuck to a lathe as a permanent feature, I'd happily risk it to get the odd job done. Point is it's a mistake to overload machines all the time, but thay have a safety margin that can be exploited occasionally. Don't take the p*ss though, best get a bigger machine when lots of heavy work is to be done.

Easy test. Put the big chuck on and use it to grip a suitably heavy lump of metal. Then put 360 hours of work on the bearings, gears, belt and motor by leaving the lathe running continuously for 15 days. Would it be a surprise if this caused a problem?

Dave

Normal everyday wear is my 4 inch 3 jaw, I have a 5 inch for when it could be useful, a four jaw scroll chuck is also in my collection. Apart from the extra weight of the 5inch chuck it also extends the overhang distance from the bearing so increases the forces from cutting applied to the bearing, this can be mitigated by using a centre to support, people are used to thinking of the job overhang from the chuck and using a centre or steady but forget to add the extra from a big chuck.

Mike

The thought of cutting a bigger gap into a lathe bed with a hacksaw, or angle grinder, appalls me. It will weaken the bed, and so may well affect accuracy, by making the bed more flexible.

Granted, there ARE times when needs must, and the devil drives!

Risking the wrath of Myford owners, in my book, the ML7, and it's offspring, is too flexible anyway.

Confessing some of my many prejudices, I learned on industrial machines, and so am a graduate of the "Brick mausoleum" school of engineering.

Which is not much good for aeronautical work, but does explain why so many Victorian machine still survive!

Howard

.

In what sense is the Speed 10 “offspring” of the ML7, Howard ?

There is much that sets them apart, and relatively little in common

MichaelG.

Horses for courses springs to mind, would you use a watchmaker's lathe to machine a 8" flywheel?

No, then there are reasonable uses for Myfords as well as industrial size machines in the right environment. History of ME proves the case.

I think you will be ok for home use, but sometimes a bigger chuck cannot hold much bigger work as the jaws are also bigger, and tend to hit the bed earlier. The biggest chuck a lathe can hold, safely, or not is the one that allows the maximum safe extension of its jaws to clear the bed. People frequently fit 125mm chucks to 7 x 12 Chinese lathes, I was happy with a 100mm four jaw independent on mine.

For the occasional job you might look at faceplate dogs which with a little thought you could design yourself to give greater capacity than a chuck.