Recomendations for a Keyless Chuck?

[Roger BestParticipant @rogerbest89007]

Thanks for all the diverse advice from everyone.

I did make at least one mistake – I now think the chuck is undersize, rather than the arbour too big. Explanation will have to wait till I post the pictures. In short the taper does not penetrate 24mm, only 21 or so. As observed above, it only takes a tiny difference in the diameter to cause that.

However, the very gracious Ian Davidson has persuaded me that its a good product, and I have come home to find other arguments to that effect and that this level of protrusion is normal, so all is well and I feel better about everything.

The only problem is that after jamming it on good and hard the runout is now a little worse, it would be so nice to get it down to 0.04mm.

[JasonBModerator @jasonb]

It may be a combination of various run outs in the spindle, arbor and chuck, you don't need much to alter the dti rading by 0.01 either way depending on how the various parts line up. You could try the chuck in a different position on the arbour.

From measurements of my own ARC Chucks and Arbors I would say it is a bit of both, chuck possible very small amount under size and arbor slightly more towards the large side. as I measure the 15.73 between the 24mm gauge length and where the chuck goes up to which like you is 21mm, I get about 15.8 at the 24mm gauge length.

[Roger BestParticipant @rogerbest89007]

Hi folks

I have uploaded some pictures. My first impression that the taper was an incorrect fit was because it protruded so much more than the original chuck.

So after all the discussion I marked the male taper 25mm up, ignoring the chamfer. This was a mistake, the chamfer is part of the specified dimension, it should have been 24mm so take 1mm off your measurements below. I fitted the chuck by hand and there was a good gap between the mark and the top of the chuck.

I fitted the assembly and forced it together with the mill quill which I videoed. I don't think it got much deeper so maybe a squeeze in the vice or a tap with a hammer, suitably protected, is required.

Lastly for the night here is a simple picture that shows that I needed something to hold small drills.

As Jason says there is a lot of luck on those last few microns of any set up so I will have another try another day. then I will update the video or do a part 2. I videoed the runout of the chuck as jammed on and it was 0.055mm so a little worse than before and worth playing with.

There is also the drilling test to look forward to.

[Neil LickfoldParticipant @neillickfold44316]

With my mill drill, I put the MT4 arbour in the mill and kept rotating it in the spindle, to the place of the least runout with an indicator. Marked a 0 on the arbour to match the 0 that was already on the spindle dog. Then put a 6mm pin into the chuck, and kept moving that around until the pin had the lowest run reading and pushed the chuck by had at that point. checked again. Then used some different sized tools to see how they looked, like 4mm, 8mm and 10mm. Sometimes you get lucky and find the best place quite easy with some chucks, others not so lucky. Not sure who actually makes the Niraw brand sold out here with a picture of a whale on it's side. But very reasonable priced cucks with very good accuracy. I did get one that has the body integral with the MT4 arbour(Not the Niraw), and it has about 0.1 to 0.12 mm runout when fiddled with. I know that my spindle is not totally true, but is not 0.1mm out that's for sure. It does seem unusual to see such a gap between the chuck and the mandrel though. With the 4mm and 6mm carbide reamers, my good chuck runs better than 0.02mm tir. So it is only used for the work that is going to use the carbide reamers. Otherwise for clearance, holes the integral one is used. In doing the exercise, I did find that carbide blanks and pins that I thought were straight, really were quite bent, and throwing off the initial readings. The integral chuck still puts holes in quite accurately despite the run out of things. So the drills must be flexing a bit somewhere and following the spot drilled or centre drilled holes quite well.

Be interesting to see how your one turns out after the trial and error.

[Roger BestParticipant @rogerbest89007]

Progress delayed due to arrival of a new loco.

Small list of jobs required before spring testing day.

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