1. Home
  2. ⚙ Model Engineering in the UK
  3. Chuck change

Chuck change

I managed to break the chuck key tonight while using it to unscrew the 4-jaw
chuck from the mandrel of my ML7, prior to fitting the 3-jaw chuck. Luckily
I could extract the broken piece, and grind four new flats on the key, but I
wonder what the recommended method is for loosening the chuck from its
thread? The only thing that occurs to me is to use a bar across the jaws of
the chuck but I worry about damaging the jaws.
Cliff Coggin
Kent
UK
Reply to
Cliff Coggin
Loading thread data ...
Not much help this, but it shouldn't be that tight that the key breaks off. I Had one that was very tight on the threads, due to using a cheap backplate. No problem, lock the backgear, use a long lever, a few taps with the hammer, and bingo! chuck off.
Then a new backgear costs about £50.........
This explains why so many ML7s have teeeth missing from the backgear. I thought it was moving the lever into backgear when it is running, but it isn't....
I just use a short tyre lever between the jaws. If I can bend them it wasn't a very good chuck :-)
Reply to
Martin
Grab the sides of one jaw with a large adjustable spanner and heave. Have the outer edge of the jaws roughly flush with the chuck body diameter. This provides maximum leverage and ensures that forces are not transmitted to the scroll or the scroll bearing.
This is pretty kind to the chuck but the back gear is still the weak point. If all goes pear shaped and you break a tooth at least you had the comfort that you used minimum force and broke it gently !!
jim
Reply to
pentagrid
I quote the Myford ML7 manual:-
(11) When removing a chuck (or faceplate), do not 'yank' the chuck off with the headstock locked with the back-gear, but set the headstock for normal back-gear drive, and after placing a piece of hard wood on the lathe bed, pull the spindle round by means of the belt so one jaw of the chuck or slot in the faceplate strikes the wood sharply. The most obstinate chuck is released in this way, and a great deal of the load is taken from the back-gear teeth.
I have used this method once or twice and it does work. I must admit that my normal method is to use the chuck key with the back-gear locked, but I do find the 'Myford method' useful if the chuck has got itself stuck on as a result of interrupted cuts.
Mark Rand RTFM
Reply to
Mark Rand
I have been taught to NEVER use the chuck key to remove screwed chucks (Like Myford). I open the jaws enough to insert a short length of hardwood between the jaws (about 18 inches of 1 1/2" x 3/4" Jarrah) across the chuck, lock the spindle and give the end of the wooden bar a whack with my hand. The chuck comes loose every time and the wood will not bruise the jaws at all.
Charlie Stone (Western Australia)
Reply to
Charlie Stone
Does it ever bruise the hands?
Mark Rand RTFM
Reply to
Mark Rand
Bruised hands will recover on their own; bruised jaws cost money.
Cliff Coggin Kent UK
Reply to
Cliff Coggin
How do you effectively lock the spindle? By putting on the lowest gear ratio?
Reply to
Airy R. Bean
The way I used to take screw off chucks of was (this was a 12" taper scroll chuck on a very old Ward lathe but I think the idea could be used on smaller with a bit of care)......
using a good strong piece of wood (I used to use a bit of 3" X 2") tighten the jaws onto it, and rest it on the rear slidway, then engage the slowest gear in reverse, there would be one almighty bang and the chuck would come off first time (although I did once manage to break the wood)
HTH
Reply to
Tim Bird
The Myford has a built-in spindle lock (found under the change wheel cover next to the spindle). And the force needed is not all that high, it doesn't bruise the hand at all.
Charlie
Reply to
Charlie Stone
?????????? What model Myford ? I have owned 3 ML7's one C7 capstan and one S7. None of mine had a spindle lock. Just curious.
-- Regards,
John Stevenson Nottingham, England.
Reply to
John Stevenson
It is a Super 7 circa late sixties. A rod (about 3/8" dia) that is located with a ball and spring detent to stop it floating about is pushed into a hole machined in the spindle pulleys to lock it up. It is definitely original equipment.
Reply to
Charlie Stone
Yep - my Super 7 had one too. -- Steve Blackmore
Reply to
Steve Blackmore
There is one fitted on my ML7R too. I think the 'R' variant has a super 7 head and tailstock on a standard bed and fitted with standard saddle from what I can recognise.
Bob
Reply to
Bob Minchin
By the time a piece of Jarrah gets to Britain, it probably costs more than its weight in gold!
It certainly wouldn't be used for bashing a chuck off a lathe!
In the days when things were done properly (i.e, before British Rail) Jarrah was frequently used by the "better" railways for sleepers, on account of its properties. Since they can't afford such sensible things nowadays, they have to use steel or concrete - the former a non-renewable-source material, and the latter prone to snapping! (If in doubt on the latter, take a close look at some of the present-day main lines - they are easy to spot :(
Dave.
Reply to
speedy2

Further Reading

  • What key for this chuck?

  • I just got a drill chuck marked RJ3-16L It's a 5/8 chuck.What key will fit...

  • Chuck key identification

  • I've got a mangy old benchtop drill press that's still in reasonably...

  • Chuck Key for Lodge & Shipley Collet Chuck

  • I am looking for a key to actuate the closer on a collet chuck Iacquired. The...

  • Using Brass Round to Lap Chuck Jaws

  • I was reading up on lapping chuck jaws and came across the threadabout using a...

  • Jacobs chuck

  • Someone at rec.crafts.woodturning suggested I post my query here. Belo=w is...

  • Where to find an 11/32" lathe chuck key?

  • I recently purchased a used 4-jaw chuck for my Atlas 12" lathe.The problem is...

  • Mini Drill Chuck Key & Belt

  • Does anyone know how to identify the sizes of 'Jacobs'-type chuck keys?I...

  • chuck key

  • What number chuck key do I need for a 1/2" cap. chuck with a 15/64" pilot? Is...

  • Metric Chuck Key?

  • I picked up a Chinese drill chuck cheap today at the flea market. The chuck is a...

  • Rohm Chuck Disassembly

  • I have a Rohm Supra 1/2" chuck. It has a JT6 taper and a 1/2" straightshank...

  • Chuck Key for South Bend 4 Jaw

  • I recently purchased a model # 4006 South Bend 6" four jaw manual lathe chuck...

  • lathe chuck runout

  • I just got the first 3 jaw chuck for my lathe. I was using a 4 jaw for the last...

  • Chuck key magnet

  • For 30+ years I've had my chuck key chained to the drill press at home. Not...

  • TdeG chuck question

  • I recently bought an Astra Meca semi-universal dividing head, which came with a...

  • Need help identifying old Delta Drill Press & need chuck key

  • I was recently given an old Delta Drill press (see photo at address below). The...

  • Wanted : hydraulic cylinders / Indespension units

  • Looking for 4 hydraulic cylinders about 2" stroke and 2 1/2" to 3" diameter,...
  • « previous thread

  • Threading questions

  • Two questions please from of novice at metal working. [1] I have been...
  • next thread »

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.