Play in new arbour for mill

Hi,

Have a question, I am new to milling but got myself a 2^nd hand mill and just bought a new Arbour and Drill Chuck for it. Before joining the two together I put an indicator dial on outgoing shaft of the arbour while in the mill rotating. The "play" in the shaft was about 1.5mm. I tried to reseat the arbour a couple of times but 1.5mm play was the best of all three times.

Would you say this is not bad "play" for a £50 arbour ??? or should I return it and ask for another one?

What size and fitting is it?

..that sounds rather a lot of money for a drill chuck arbor..?

Totally unacceptable. Return it and get a refund. 0.15mm would be just about ok.

I'd say it is a masive error for a £10 arbor let alone a £50.00 one. Should be looking for about 0,015mm or less.

Have you checked the spindle and/or something else in the taper to see if the 2nd hand machine is the problem?

How many divisions on your gauge was the needle actully moving, sounds like you may be reading it wrong unles steh needle was making about three ful revolutions.

Edited By JasonB on 16/09/2023 19:31:48

Exact and more details are important, terminology is as well. Since you mentioned checking with an indicator I suspect you mean run out and not play as each has completely different meanings. But if you mean play as in the arbor is still loose? As Diogenes asked, what spindle taper is the machine? And 1.5 mm / .060" shows something is very wrong. Unusable in fact. At most it should be around .025 mm / .001" or less for a decently ground arbor. Either you have bought the incorrect arbor taper for it, or on something like a R8 taper machine, possibly the spindles internal key isn't engaged with the side slot in the arbor. If it is R8? The arbors front taper should be pulled up fully within the spindle taper and almost flush with the end of the spindle. About all you should then see is the bottom taper that accepts the drill chuck taper below the spindle nose. That can only be done if the side slot is indexed properly to engage with that internal key.

+1

A photo would help.

I'm wondering what the word 'play' means. My first thought was run-out, that is the arbour axis is misaligned with the mill's spindle axis. If so 1.5mm is huge! Second thought is 'play' means the socket goes part way in, and there's an all round gap in which it rocks. If so that suggests the tapers are mismatched - the arbour's male taper doesn't match the taper in the mill's socket. Several different tapers are available, and identifying them often causes bother.

Dave

Edited By SillyOldDuffer on 16/09/2023 19:54:46

Earlier posts seem to suggest INT40 in a Beaver Mill

Hi guys - sorry yep its a INT40 in a Beaver Mill. Give me 2mins will try and post a photo of the dial.

Hi, so hopfully i am readying the dial correct... the movement is from 0 to 15. I take that as 1.5mm.

Will see if i can get a screenshot of the "set-up" i done.

Each small division round the large scale is 0.01 mm as is printed across the dial. So that's 0.15mm TIR which isn't bad though not wonderful.

Yep 0.15mm whch is still not that good,

Put the indicator into the spindle taper and see what that reads.

Hi guys,

I throught as the dial noted 0 - 10mm each "10" was 1mm. I take it I was completely reading this incorrectly.

The internal face of the INT40 and the arbour face look fine, I cleaned them and wiped them down with cleaner to get rid of any oils.

Would you agree its best to send this back and ask for another arbour ?

.

I think you have probably ‘got it’ now, Antony … but the 0 - 10mm reference means the total travel is 10mm

… The little dial counts rotations of the big one.

MichaelG.

That is the trouble with thought, it can mislead you. Best not to think but to test the indicator with something of a known dimension (thickness) and see how much the indicator moves. For instance, a search could tell you the thickness of every coin that is legal tender in the UK. Passing one of each of those under the indicator would teach you a lot.

Given how badly thought can divert you from truth, 'look', as you have done with the arbor face, is at least an order of magnitude worse. Now you know what each of the little lines on the indicator mean, poke it up inside the spindle, even if it is at an angle, and actually measure if there is any run out in the spindle itself.

You have paid money for the tool. Why 'look' when you can recoup some of that money?

All you can say for sure is that there is run out on the arbor. You have not yet identified or isolated the source of that runout. You will soon become bored, as will your supplier, if you return a few arbors as faulty and then subsequently discover there is an issue with the milling machine spindle.

On the left is "mm 0.01" that is what each division measures.

The "0-10" is total travel. Each complete turn of the needle will be 1.0mm and for each of those rotations the small "clock" upper centre will count upto 10.

Was there any tooling with teh machine a sthat would be something else you could clock and compare results with.

The new arbour has probably got centre holes at each end. Is there any way for you to set it up between centres, such as in a lathe, and check if it is bent? I ask this as the usual reason for changing arbors when I was at work is because someone swung a large radial drill around and clouted a vice with a drill chuck. The neck of the arbor was the weak spot that bent as a result. I would assume a new arbor without any obvious bruising is not going to be bent and that the spindle is likely the source of your runout, especially since you have tried different positions and got the same result.

The other thing to do is when you measure the runout on the end of the arbor mark the high spot on the arbor and the spindle Then see if it moves with the arbor when the arbor is tried in a different position or stays in the same place on the spindle.

Martin C

You must have other holders that fit your machine, put one of those in and see how far out that is, also have a good look at the taper in your spindle, all it needs is a bit of swarf embedded there and surprisingly in industry where your machine most probably came from the operators don’t always look after machinery as men in sheds do, also if you have them remove any spindle drive dogs, the arbor slots can be undersize and catch on the dogs causing a runout.

This is what I would do first. Turn a centre in your lathe chuck and then put the new arbor between that and the tailstock centre. Put a dial gauge on the wide part of the taper and turn it by hand between the centres. If there is runout the part is bad, if none then the spindle needs looking at.

By the way, to original poster Antony:- You've definitely earned a 'You Suck' for getting your hands on a 40 taper Beaver, even if it should turn out to need a rebuild at this point in its life.

Edited By Mark Rand on 17/09/2023 12:20:21