Thread: Chuck removal

I spent 1/2 of last weekend getting the chuck of mine for exactly the same reason

I spent quite a bit of time trying to stop the spindle from turning without using the back gears - unfortunately none of them worked.

In the end I removed the front of the chuck (take of the 3 hex bolts in the front, and work the chuck loose). I could then get good access to the first turn of thread, and get lots of WD40 soaking in. I then used a combination of the back gears and a tight grip on the belt with my free hand to give the chuck a few taps in the right direction with a copper mallot to free it.

It took a looooong time and really tested my patience, but in the end it came off,

In the picture I have attached you can see how far the WD40 soaked in and the rust that was holding it. The more oil you get to soak in, the easier it will be.

Ouch,

Weekend would have been better spent tuning steel into swath...

Mine are not rusted - I suspect one of my back plates has too much thread so it is not sitting against the Spindle but trying to cut more thread on it.

Either way they can get tight with work, and I'm sure we are not the only users inflicted but I am confident the solution(s) is out there

You could try a piece of Hardwood placed between your chuck jaws (under one jaw and over the top of another.Length of Timber depends on what you have as long as its longer than your chuck.
Put it in an adjust your jaws so its snug and give it a good hit.
It may take a few hits to loosen the chuck.
You can also use a bit of Timber as an lever under your pullies to try and stop the spindle from turning as easily.
For saftey of gearing place your Reverse Tumbler in Neutral.
When you finally get the chuck off machine your Backing Plate Threads so that you only have the Back Plate Shoulder seating on the Headstock Spindle.

Originally Posted by MarkJ

I spent 1/2 of last weekend getting the chuck of mine for exactly the same reason

I spent quite a bit of time trying to stop the spindle from turning without using the back gears - unfortunately none of them worked.

In the end I removed the front of the chuck (take of the 3 hex bolts in the front, and work the chuck loose). I could then get good access to the first turn of thread, and get lots of WD40 soaking in. I then used a combination of the back gears and a tight grip on the belt with my free hand to give the chuck a few taps in the right direction with a copper mallot to free it.

It took a looooong time and really tested my patience, but in the end it came off,

In the picture I have attached you can see how far the WD40 soaked in and the rust that was holding it. The more oil you get to soak in, the easier it will be.

that looks bad ah dont you wish you had a cam lock chuck lol

I'll second what Pipeclay has said, follow his advice and your doing it "right".

When you have relieved the threads in the backing plate so that the shoulder hits, then make sure the thread on the lathe and the threads in the backing plate are squeaky clean, before you screw it all back together again.

No gunk, means that it will come off easy next time, endear yourself to the other half, go swipe her toothbrush and use it, to clean the threads in the backing plate.
regards radish

As above. Also, don't leave WD-40 on the threads-it will soon turn to a gummy residue, then harden over time. I had a Taylor three jaw so frozen on my old machine that I had to sell it with the headstock when I parted it out. It's probably still there.

You might also try a strap wrench on the chuck body. There are other good tips on the various South Bend forums, dedicated to the Hercus' ancestor.

Following on from Greg's comments, the following Practical Machinist South Bend link has some good tips.

http://www.practicalmachinist.com/vb...=chuck+removal

Ken

Hi all well I have been there and done that and some of you will probably condem me for this
I use a electricians size screwdriver and wedge it between the tumbler and the idler below
As these gears take all the force of the machine I found after many goes that this was the easiest maybe not the best but it worked
I had a piece of pipe in the chuck held the stilsons on the chuck with one hand and held the screwdriver with the other

I always put a dab of grease on when I fit a chuck to prevent it seizing

Another old method is to find the old steel brake hose clamps and loosen the belt put on the clamp and reclamp the belt with a bit of a adjustment the brake hose clamp just stops the belt from moving

But yes there are some that are determined to stay on as I have found which has since I am usually pulling them apart I put the mainshaft in a vice with some soft jaws and the same bit of pipe and stilsons does it's job again

But as my first lathe had never been off it was a horror I jambed all the back gears and the tumblers with a chisel and still no go so as the good old WD40 and 2 weeks later it fell off

I am not proud of doing things this way but if it has to come off I will try and do it with the least possible amount of damage

I have been looking at grinding the end of the mainshaft to put 2 flats on but it would not leave much metal so that was scrapped

To whoever can supply a easy way please let us know as having wrecked a few Hercus's I still am not happy with locking the tumbler and idler

all the best Derek

Thanks all,

What great info...

Ken That great link is where I was thinking because I was bit loathe to stick something in the jaws of my new chuck and belt it, likewise jam up any gears - they are too scarce.

Couple of good points in that some have used the the back gear lock without an issue, and as Bitza says locking the gears has worked for him - and he has gotten a couple apart - just make me nervous....


Clearly the issue is not to have them so tight in the first place, but as many of us are re-birthing old machines it is probable .

Now it off I'll machine the backing plate thread back a tad. Also interested in the point of using steel backing plate - not sure why that is an issue. Does steel on steel bind ?

Do you think a machined insert in the end of the spindle would help protect the spindle against potentially being deformed when clamped.

Cheers

Ian

Just a thought about holding the spindle.
Why not use a shaft or arbor with a MT3 taper and lock into the spindle similar to a milling machine? Could easily be adapted to another spanner at the front, with chuck fixed with a packing block.
Also heat the thread area with a hot air blower (a paint stripper or the daughters good hair dryer) beforehand.
Use a metal antisieze/heatproof grease with copper or silver on the spindle thread to stop future problems. I always used this grease on car wheel studs and was always able to remove by hand crank.
Regards, Peter

Godzilla,

I have been using a couple of steel backplates for over 20 years - no problems yet.

Another tip for removing a difficult chuck which I have heard but not tried, is to grip a piece of suitably sized hex in the chuck and use an air or electric impact wrench on it. To me, it sounds that this approach, if it works, would be easier on the lathe and chuck than some of the common alternative approaches, such as using a long piece of timber held across the chuck jaws and applying a suitable amount of persuasion with a large hammer.

Frank