Good MT5 collet holder recommendation

[Sonic EscapeParticipant @sonicescape38234]

Finally I managed to remove the chuck from my lathe. The screws were in very bad shape. I want to use some kind of collet, preferably ER type, to avoid the lack of repeatability of the 3 jaw chuck. I discovered that is had an MT5 spindle. I measured the runout on different positions on the internal taper. To my surprise the error is very small. I think it is +/- 1µm! There is some wear on the bed and I was expecting the spindle to also have some issues.

I have an ER32 MT5 collet from my milling machine. But it is an no-name AliExpress style. When I put it on the spindle the concentricity error on the collet taper jumped to +/- 10µm. I suppose there must be better holders. What are some good brands?

Until a few days ago I was looking for a small lathe to have more precision on small parts. But now I’m thinking that if I could preserve the small runout of this lathe down to the collet holder then it would make no sense to buy another one. So I have a decent (I think) budget for a good holder.

[JasonBModerator @jasonb]

You would do better using a backplate mounted ER chuck as that will allow you to hold any length of material. The Tapered shank of an MT5 will block the spindle so only short work can be held.

[Sonic EscapeParticipant @sonicescape38234]

That is a good idea. But I measured now the runout of the backplate and it is +/-2 or 3µm. Depending on the spot. The spindle taper is more precise. Those arceurotrade ER chucks don’t have any specs related to accuracy. This is not a bad sign?

I just discovered that there are MT soft blank end arbors. If I could find an MT5 model I could make the perfect collet holder 🙂

 

[John HaineParticipant @johnhaine32865]

I think you would find that an MT5 ER collet chuck would be severely limiting because you couldn’t hold any length stock and it would stick out too much.  Jason’s suggestion of a good quality backplate mounting ER chuck is much better.  I bought one for my Super 7 that has a separate backplate that screws onto the spindle nose then the register is turned true to the spindle axis.  I use ER40 collets and have no problems with runout though I’m sure it isn’t zero.

[RobinParticipant @robin]

I bought a no-name Chinese MT5 ER40 adapter for my lathe with one 18mm collet and two large spanners to wind it shut.

At first it was inaccurate. I cleaned the spindle taper and it improved. I went on cleaning the taper until perfection was achieved. I did wonder if the MT5, ER40 market is less hobby-orientated and less willing to buy crap? Or did I just get lucky?

I don’t think the lathe maker expected me to use MT5 tooling, the thing came with an MT5->MT3 adapter. I think they knew I was more likely to buy it with the 40mm spindle bore and I probably hadn’t appreciated the consequences for the taper. They were probably right 😀

Robin

 

[DiogenesParticipant @diogenes]

ARC collet chuck, stuffed straight onto the nose of Warco GH600..

https://www.youtube.com/watch?v=-SMNIVJcSuE

 

[Sonic EscapeParticipant @sonicescape38234]

That is perfect! I need a 160mm backplate mounted ER chuck. It looks like most of the are bellow 125mm. This one is the right size but has very poor concentricity.

[Sonic Escape]

On 10 May 2024 at 09:38 Sonic Escape Said:

…When I put it on the spindle the concentricity error on the collet taper jumped to +/- 10µm. I suppose there must be better holders.

On 10 May 2024 at 09:38 Sonic Escape Said:

When I put it on the spindle the concentricity error on the collet taper jumped to +/- 10µm. I suppose there must be better holders.

10 microns? That is about 3 tenths of a thou. Good enough for most lathe work. An amateur in a home workshop without controlled temperature and calibrated top quality measuring equipment would struggle to even measure to that level of precision. For most lathe work, if you can get total indicated runout within one thou (25.4um) all is well.

[JasonBModerator @jasonb]

There is no real reason you can’t make a 160mm backplate to take a 125mm collet chuck. Or even the other way round, I have a 160mm chuck on a 125mm backplate.

 

[JasonB]

On JasonB Said:

There is no real reason you can’t make a 160mm backplate to take a 125mm collet chuck. Or even the other way round, I have a 160mm chuck on a 125mm backplate.

 

But how? I can drill new holes in the backplate but there is also a shoulder that should match.

[JourneymanParticipant @journeyman]

This – Collet chuck fitting for WM250 – may help, at least will give you an idea of how it can be done.

John

[JasonBModerator @jasonb]

A backplate is a separate part, it is not the flange on the spindle nose.

You machine the backplate to fit whatever spindle nose you machine has and bolt it to the nose. Then with it help like that you machine the other side to suit the chuck

[Sonic EscapeParticipant @sonicescape38234]

<p style=”text-align: left;”>Now I understood, thank you</p>

[Author]

Posts