Dmt 450 runout and Chuck removal

[Mark Hancock]

Thanks for that.

I have never removed the jaws, I guess I am using wrong terminology. The toolpost site lists them as "jaws", but all I am removing are the two threaded screws and swapping between jaws (adaptors).

I bought two sets of jaws with the sorby chuck, and they came separately boxed, so there was never any respective identifying numbers, and they cannot have been matched to fit - that's what has me unsure as to whether this is the issue.

Sounds like I just need to try it!

Mick explanation works for Axminster chucks where the jaw carriers can be removed but all other chucks, as far as I am aware, have a safety feature which means that the carriers cannot be unwound out of the body of the chuck without removing the safety/stop pin. With these chucks changing the jaws does mean unscrewing each jaw from it's carrier and reattaching different jaws. So in theory the carriers should be in their correct position if it is as it came from the supplier. Regarding the jaws, some manufacturers do number the individual jaws (as opposed to the carriers) and others don't.

 

[graduate_owner]

Hi Wcndave,

If you can't get a C-spanner or if a rod in the hole of the spindle won't work, you could try a strap wrench (as used for removing vehicle oil filters, only smaller). You might possibly be able to get a strap wrench around one of the pulleys to give a better grip. Perhaps even a rope around the largest pulley, knotted and twisted with a bar to tighten it may grip the pulley enough.

Before you refit the chuck, make sure you clean the internal thread of the chuck and the external thread of the spindle. Also make sure you fit the chuck fully on the spindle before turning on, because if there is any free thread the inertia of the chuck will cause it to spin tight and this can be very tight indeed. Also clean out the internal taper on the spindle before fitting any (cleaned) taper accessories such as centres.

Also try a washer on the spindle as previously suggested.

Sorry if this is all old hat, but I thought it would be worth mentioning.

K

 

[wcndave]

No, all good advice.

I have been cleaning regularly.

The things about attaching jaws to carriers, I found that the grooves in the jaws and the machined threads meant there was effectively no play.

I will try though to gently bring them together before fully tightening, that might help.

Thanks so much to everyone for taking the time to help!

 

[CHJ]

Knocking noises from the headstock, assuming the drive belt is sound and the drive pulleys and linkage are not just rattling is an indication that a bearing is worn or has debris in it.
To prove this Hold a large screwdriver with the blade in contact with the headstock near the bearing location and rest you ear against the screwdriver handle, normal smooth bearing whine or a rumble and any associated unwanted noises will be evident.

Operating unloaded may well show no apparent run-out without good dial gauges.
To check for worn bearings use the wood batten as previously described to apply sideways pressure to the spindle and look for flexing.
Also apply fore and aft pressure to the chuck rear and front to see if there is spindle end float.

 

[wcndave]

Here is a video if that helps, really hard to tell where the noise is coming from.

https://www.youtube.com/watch?v=4O3yCen ... ata_player

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[CHJ]

If you change belt positions what is the effect on the noise?

 

[wcndave]

At higher speeds or sounds smoother of course. I have another of dial on original faceplate. https://www.youtube.com/watch?v=7WMoJEP ... ata_player

And one with Chuck https://www.youtube.com/watch?v=9Yva_DF ... ata_player

about 0.1mm from that.

Both ear against and wedging wood and testing seem a little redundant but I will try the wedge now

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[wcndave]

Maybe I understand the wedge wood now... one quarter rotation I can do with one finger, the opposite quarter takes my whole hand..

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[CHJ]

By checking different positions with the ear you should be able to determine the location of loudest noise, this should lead you closer to source.

Is there by any chance dust debris impacted in the belt grooves at one or more points? This would create a similar noise and produce the stiffness on rotation as the belt tightens as it tries to traverse the pulley.

 

[Spindle]

Hi

What is the run out on the drill bit? Measured as close as possible to the chuck

Regards Mick

 

[wcndave]

The Chuck is definitely tightening against the wood. This also happens with the belt off.

My next experiment was to put scotch tape around register and put chuck on, no damage to tape. With blue tape it went on ok, however did mash the tape up a little bit.

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[wcndave]

Calipers out and chuck register is 34.1 whereas spindle register is 33.94...

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[wcndave]

https://www.youtube.com/watch?v=0jL2eRO ... ata_player

Run out on drill bit, which I must point out its held in carriers, not jaws is about .2 mm

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[YewTube]

I am a little late to this thread but can I offer the following suggestions.

1. Ticking noise.
Check that the belt pulleys are are tight and in alignment. They are held in place with grub screws which can come loose and allow the pulley to go slightly out of alignment. I had a similar noise caused by the belt trying to ride up the side of an adjacent pulley and making a click as it dropped back.

2. Run out.
To reach a conclusion of where the problem is you need to measure the bare spindle.

If you measure a faceplate, chuck and drill bit you are compounding the errors. In some cases the errors may add together to give a bigger error or subtract to reduce the error. Either way it is not possible to make an informed judgement.

Bill

 

[Spindle]

Hi

With a spindle run out of 0.01mm and 0.2 at the chuck I wouldn't worry about trying to improve things, (the wood will move more than that during the turning process).

If you can't find any play in the headstock bearings you may need to look at your technique / tooling / materials to address the chattering.

Regards Mick

 

[wcndave]

The problem is that the run out makes it impossible to create a cylinder, especially when using a jam chuck, or if I need to remount a piece...

Any slight movement, and the piece is eccentric, which I think causes the chattering.

The face of the chuck is also out quite a bit. which makes me think it's not mounted properly, however it is tight against the spindle back.

A couple of the threads on the spindle are a bit damaged, and I wondered if that was holding back one side of the chuck. I removed some of the burrs, however no difference.

 

[CHJ]

The problem is that the run out makes it impossible to create a cylinder, especially when using a jam chuck, or if I need to remount a piece...

Any slight movement, and the piece is eccentric, which I think causes the chattering.
...

A chuck or faceplate that is solidly mounted on a true running spindle with no bearing slop will make no difference to turning a true cylinder, you can do so even on a eccentric displacement chuck.

I suspect that your chuck is not mounted correctly regardless of it feeling tight. Is it by any chance bottoming out with the internal bore bottom face hitting the spindle end.

To turn something other than a cylinder either the chuck is wobbling (twisting during the revolution) on the spindle nose or the spindle bearings have side float.

Have you taken the spindle out and checked that it is not bent, or at least dial gauge checked the spindle nose.
Have you turned a spindle between centres, is that a true cylinder?

 

[Doofusme]

"The problem is that the shaft hole that you see in the picture is only a quarter of an inch deep, so putting anything in it to lock the spindle just doesn't work."

Take a look at this 3rd paragraph down

http://www.laymar-crafts.co.uk/tip53.htm

For a modification to help yo with this roblem.

Regards

Phil

 

[wcndave]

A chuck or faceplate that is solidly mounted on a true running spindle with no bearing slop will make no difference to turning a true cylinder, you can do so even on a eccentric displacement chuck.

Ok, i see what you mean, the centre of the chuck will describe a circle, however this will be inside the exact circle that one is turning

However the problem is remounting. If remount anything in the jaws, it is out. If i remount anything on the steb centre it will be out. I can do this with the morse taper, however i got the steb to avoid removing chuck all the time.

Also for the birdhouses on page 1, I have a cylinder which is use as a jam chuck. If i don't mount the cylinder exactly as before (and i may well have removed my chuck/steb/jaws in meantime) it will be eccentric for the next piece of work.

Also i have some reverse mounting bowl jaws, again mounting in here with a wobbly chuck will cause issues.

I suspect that your chuck is not mounted correctly regardless of it feeling tight. Is it by any chance bottoming out with the internal bore bottom face hitting the spindle end.

This was something that happened when i first got the chuck, as the scheppach has a long nose. However i got a mate to extend the collar at his metal works, and it is tight against the shoulder of the spindle.

To turn something other than a cylinder either the chuck is wobbling (twisting during the revolution) on the spindle nose or the spindle bearings have side float.

Have you taken the spindle out and checked that it is not bent, or at least dial gauge checked the spindle nose.

Looking at the lathe i could see no easy way to do this, so likely to be a pain. I did check the nose, and the scheppach provided faceplate, and a morse taper. All were within 0.01mm in all directions...

Have you turned a spindle between centres, is that a true cylinder?

Yes, well, true enough for me ;-)

 

[CHJ]

You are never going to re-mount any of the average wood species back in a chuck and get perfect alignment.
Wood moves and compresses at different rates dependant upon the grain direction and even with exact re-alignment of the piece in the corresponding chuck jaws the chances are that the wood will have relaxed and moved whilst off the lathe.

Using something like box or one of the very dense hardwoods works reasonably well but realignment within 2-3 mm with most pieces is as much as can be reasonably expected in my experience.