Collet chuck runout issues/question

[NT_2112]

Hi all.

Please take a look at the video.

Would a drawbar help reduce the wobble?

Is this excessive run out?

Would I be better off with a mounting a plate style collet chuck using bolts like the 3 jaw chuck?

Thank you for your time.

 

[Dick Mahany]

It looks to me like your collet chuck is being run on a mini metal lathe? If so is the mount a MT3? I haven't had the best runout with a MT3 ER32 collet chuck even when using a drawbar. I have also experienced that a long blank such as shown can often have the tail whip that I see in the video.

The collet is extended a considerable distance from the spindle and that likely isn't helping, but it may be fine especially if you use a live center in the tailstock to help stability.

I've used that type of collet chuck to successfully make many TBC bushings, and while not perfect, they have been quite suitable for good results. Try chucking a true cylinder rod of a stable material, then use a dial indicator near the collet to see if you can influence the trueness by tapping on the OD of the collet lightly. If it does move around, clean your tapers thoroughly and try again.

 

[NT_2112]

It is a MT3 hole and MT3 shaft.

 

[Dick Mahany]

It is a MT3 hole and MT3 shaft.

I edited my post above, but check that both the internal and external MT3 tapers are absolutely clean. BTW Rochester was my home town (Webster/Ontario) many years ago.

If the internal taper is in need of more than just a cleaning, a set of MT3 taper reamers can be had for less than $40 and if used gently may help.

 

[Mortalis]

Having the blank extend that far out from the collet is going to exaggerate any "wobble". Can you tighten the collet up any more? Is the end of the blank that is in the collet perpendicular to the axis of the blank or is it just cut off or even worse, raw cast? Try not seating the blank completely against the back of the collet. You may need to rotate the blank a bit in the collet to get it to run concentric. The blank may not be exactly round.
Many reasons for that to wobble at the end like that.

 

[dogcatcher]

After turning a square round the wood will move a little. Pool cue makers remove very little wood every few days over a period of time. Is that the problem? No clue, it could be the chuck, the collet, or all of the other reasons combined.

 

[Curly]

It is a combination of a couple things. As dogcatcher said, the wood has moved some. Get a ground rod to check against. Because of the long length of the collet chuck and the wood in it the runout is exaggerated. A drawbar will not improve the runout in the slightest but it will keep the taper from loosening under vibration and coming out. A flange mounted collet chuck will reduce the overall length thus reducing any runout at the work. What might be happening is that you might be installing the collets incorrectly into the chuck. They are supposed to be tipped into and under the circlip in the nut. The groove around the top of the nut when seated properly will be on both sides of the circlip, capturing it. If you put the collet into the chuck and then the nut and tighten, it will not necessarily be square to the axis of rotation.

 

[darrin1200]

As Pete said, maybe your collet is not seated properly.

One of my chucks, that mounts in a 4-jaw chuck the collet does not click and lock into the collet nut. It's like the lip only goes part way around the inside of the nut. I have to hold the collet nut in a specific orientation, so that the collet will hang in place by a sort of hook and lever principle. Kinda hard to explain. The chuck works just fine, with almost no run out. But if I don't hold everything properly, the collet slips out of the lip and doesn't lock correctly.

It's a bit of a pain, but it works. My goal is to replace that chuck with a D1-3 collet chuck.

 

[TonyL]

In addition to the above advice, I would first determine if the blank was round by rolling it on a flat surface. My guess is that you determined that already and now you suspect the chuck. I hope you get to the bottom of this.

 

[monophoto]

All very good suggestions.

Another point - the blank is round, but is it mounted in the collet such that the axis of the blank aligns with the axis of rotation? I always leave a center dimple at the end of the blank that I used to align it to the tailstock live center before clamping down on the collet.

 

[howsitwork]

I think the above should cure you're issues , that is quite a lot of overhang from the lathe headstock to end of blank though. Anything you can do to reduce that extension should help you.

Setting it between centres before final collet tightening is a good idea , do you need to have the tailstock missing??

 

[NT_2112]

Thank you everyone.


I think the runout on the MT3 chuck is too much. It's of questionable origin and may be more trouble than it's worth.

I ordered one of these from amazon. https://amzn.to/3mtVOr9



Thanks again. I appreciate the feedback.

 

[NT_2112]

Quick followup.

The new collet chuck plate works much better.

Going with the Chicom cheap MT3 option was likely a waste of money.

Thanks again for the feedback.

 

[Curly]

Good to know what solved your problem.

Just so you know in metal machining the rule of thumb is 3 diameters of the material sticking out of the chuck unless supported by a tailstock centre or a steady rest. While you can push that to some degree depending on the material you should have support for material that long. It reduces chatter and surface finish issues, not to mention being safer.