Recomendations for a Keyless Chuck?

Ketan, Interesting & informative read as I like all things engineering.

Tony

Interesting, I always thought that chuck removal wedges were used as a pair so that they remain parallel to both the arbor shoulder and the back of the chuck and avoid bending forces.

I had a look at my collection of chucks and on many of these the back of the chuck is quite a way from shoulder in the arbor probably not such a large gap as the OP's but wouldn't work with standard (thin) chuck removal wedges without packing but would brobably be OK with the Albrecht ones.

John

One advantage of the standard keyed chuck is that the body can be drilled and tapped for a jack-off screw; the same hole can then be used for a (smaller) retaining screw.

They are used as pairs, much better engineering.

Tony

The Jacobs style 'thin wedges' are sold and used in pairs.

I have observed the thick Albrecht ones being used as singles as well as pairs. Although it feels better for the Albrecht ones (or any other) to be used as pairs, sometimes these wedges are too thick at the slimmest part to fit into the gap in between the chuck and the arbor. I guess it depends on the application.

Many moons ago we purchased the Albrecht ones for use in our own workshop (now mothballed) in singles rather than pairs. We also used pairs of the jacobs slim style, and we made a few of our own... all depending on application.

We stopped selling the slim wedges a couple of years ago after the maker closed down.

Ketan at ARC

The reason why we had different wedges in our workshop was for the purpose checking different chucks on arbors.

Question for those who may know: In normal use environment, why would people need these wedge/s?, unless the JT/B taper is a permanent part of the spindle, or the wedge/s are being used in a muti-tool type assembly... such as the one used in a multi-purpose live centre set.

I mean, once the chuck and arbor are assembled correctly, why should there be a need to take the assembly apart?. If the chuck becomes faulty over time, it should be cheap enough nowadays to buy both the chuck and arbor NEW, doing away with any damage when taking the assembly apart.

Ketan at ARC

You should know by now how deep the pockets of many model engineers are compared to the length of their arms, they would rather spend £5 on a pair of wedges than £6 on a new arbor Either that or spend 3months contemplating and finally making a pair of wedges.

I see in an Albrecht catalogue they show their tool (not described as a wedge) being used as you show with a lever action.

Ketan

Sometimes the male taper is formed directly on the end of a machine spindle, eg drilling machine spindle, and if the chuck becomes faulty the wedges are used to remove the chuck ready to replace it with a new one.

Rod

Ahh I see. I am familiar with the JT/B taper being a part of the spindle, where the wedges become essential... as is the case in a SIEG X0 mill.

As I am not too familiar with drilling machine spindles, I failed to take that thought into consideration.

Thank you Rod... learned something new (to me) today.

Ketan at ARC

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.

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.

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.

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.

Progress delayed due to arrival of a new loco.

Small list of jobs required before spring testing day.