One way with a chuck

[goldstar31]

Almost 5 years I bought a cheap but new 100mm 4jaw SC Chuck for a Myford but never really got down to using it.
Now I find that it wobbles- which is not a good thing.

OK, I'd read that it can be 'improved' and recalling other advice from the past, i split the chuck from the Myford backplate.
If all else failed, I could do many things with it but the first thing was to take a 'Truing cut' of the back plate 'in situ'
I bolted it up with the 4 star socket screws and some wobble was corrected. It perhaps would improve with more attention, so I left the backplate on the lathe spindle and reduced the register a few thous in diameter. As a test, I simply chuck a bit of 'round' and much of the off centre had gone. Time to mike it and if neccessary either enlarge or elongate the 4 fixing holes. Happily, I found there was a thous or two 'airspace' to move the chuck.
Out with a soft hammer and a clock and that bit of 'round'.
So far it is really at lot better than some of the chuck that I have had.
The next is to refine thing by drilling and tapping the periphery of the chuck to tale little grub vrews and actually hold a ground piece of round to 'look for thous and then tenths( )
Before anyone rushes to tell me that a set of lathe jaws will only accurate at ONE diameter, I know.

However for what took me less time than writing this to do.

More Anon but others can probably copy the idea

 

[BaronJ]

Hi Norman,

I've recently bought a new 100 mm 3 jaw SC chuck from ARC and fitted it to a back plate that I have had for a couple of years.

I did a similar thing made the register about 25 thou small and loose fitting bolts so I could do the same tap tap with a plastic hammer to get it true, though I do prefer the aluminum soft jaws that I made for the original 100 mm PB Myford chuck.

I can get effectively zero run out with the soft jaws and about 3/4 of a thou on the new one, but yes the scroll soon runs out as the diameter gets larger. There is five or six thou difference between an 1/8" inch rod and a 60 mm round.

The thing I did find annoying, the back plate I had was stainless steel and bloody hard to machine and drill the holes in it. Interestingly the chuck can be mounted from the back or the front, although only the cap screws for front mounting are supplied.

 

[goldstar31]

Hi Norman,

I've recently bought a new 100 mm 3 jaw SC chuck from ARC and fitted it to a back plate that I have had for a couple of years.*************************************************************

Hi John

It's quite fascinating as I had a 100mm SC one and it came from my Sieg C4 but the outside jaws were missing so I bought a Myford Backplate and did the old 72mm thing and bored the 3 holes to link the two up.
Then I bought 2 pairs of soft jaws which were discounted from Axminster Tools and I have an unused one.
Sounds quite barmy but I have a spot on SC chuck on the Myford.
Today, in a fit of insanity( or not) I phoned Axminster to say that as most of my change gears on the Sieg had- gone???????, had they a set or enough to add to the ones - which were 'left'. Well, that is answer to get but I have 2 sets of Myford ones- spare as I have a gearbox. So flushed with information- or eventual Sieg gears,I asked whether I could change the rotary DRO's and fit something which my old eye could read. I bought a pair of dials from ArcEurotrade in the event that 'nothing came from Axminster.
Gets confusing- but it makes a change. Otherwise there is little do in this Covid-19 but to drink whisky in vertual isolation.

Just in case of doubt, I actually live on an estate which once supplied food for the local home for people who wear are- inmates. All very logical as I will not have far to travel-- when my turn comes. To that event, I have changed the tyres and tubes on my little electric disability scooter.
Meantime best regards to all!

 

[Apprentice707]

I did the same with a 4 jaw SC chuck some years back. Now it is my standard fit chuck, after all, I don't machine much hex bar mainly round and square.
Why can't some decent chuck manufacturer produce a good quality 4 jaw SC chuck with a direct fitting threaded body for Myford, Boxford, etc at a reasonable price?
The same goes for square and hex ER collets, I am sure there would be a demand.

Cheers

B

 

[goldstar31]

I did the same with a 4 jaw SC chuck some years back. Now it is my standard fit chuck, after all, I don't machine much hex bar mainly round and square.
Why can't some decent chuck manufacturer produce a good quality 4 jaw SC chuck with a direct fitting threaded body for Myford, Boxford, etc at a reasonable price?
The same goes for square and hex ER collets, I am sure there would be a demand.

Cheers

B

I agree with the above. The difficulty is that a manufacturer has to cost in the price of an extra pair of jaws! As a sideways comment, a 3 jaw chuck will hold a rather rough round piece of bar rather better than in a four jaw. Of course, one should use am independent 4 jaw chuck--- but, but

Regarding the provision of 'other shapes and fixings', the answer seems to be a marked reluctance for most NOT to buy anything unless is absolutely necessary.

 

[johwen]

Hi,
Talking about 4jawSC chucks I have been using same for years they are so universal. Round, hex, square they will chuck up accurately I've found. Yes they will accurately hold hex just try it. But best buy a quality known brand from Europe. My current one is Polish made 125mm and will hold accuracy of a thou over its range. The Chinese variety i first used not so accurate though. John