How much is too much...

[Tinbasherdan]

So there's no taper?

Not apart from the er40 taper. I wouldn’t have thought a ding on a register would make a difference as it was machined on the spindle itself. Going to have to have a rethink and retrace my steps. I’m wondering if the spindle is slightly bent

 

[Tinbasherdan]

so this is the nose adaptor I made. You can see the join line at the top where it is screwed up against the spindle register. I can’t get my head around why it would run out when the spindle was clocked so true, certainly much much less than the 22 thou of runout on the nose now

 

[Pete.]

My guess is a bad taper angle.

 

[RichardM]

Are you just relying on the threads on the spindle to keep it in line? i.e. The piece you have made is just screwed onto the spindle nose instead of the original collect nut.

 

[Tinbasherdan]

My guess is a bad taper angle.

The outside of the block is running out just as bad!

and yes, it screws on in place of the original spindle but, but butts up on the collar on the spindle as a register

 

[RichardM]

So it just screws on, nothing to register axially on apart from the threads?
Do you need er40 specifically? What is the inside diameter of the original nut?

 

[Tinbasherdan]

So it just screws on, nothing to register axially on apart from the threads?
Do you need er40 specifically? What is the inside diameter of the original nut?

It also located on the plain nose of the spindle below the thread. I went er40 as it’s nigh on impossible to get the collets for this machine without spunking a fair wedge! And I have an er40 collet set

 

[Tinbasherdan]

Spindle as is standard, for reference

 

[RichardM]

Original collets like this? is there provision (hole) for a drawbar to go through the spindle?

 

[Tinbasherdan]

View attachment 318936

Original collects like this? is there provision (hole) for a drawbar to go through the spindle?

Yes, exactly like those. I have a drawing, and I have a quote to get some made and a full set would be worth more than the machine. There is a drawbar hole in the spindle

 

[RichardM]

Why don't you make it like this instead?

 

[Seadog]

OK, you made this on the lathe. Did you make a threaded mandrel mimicking the mill spindle to mount the part on when you machined the taper?

 

[Tinbasherdan]

OK, you made this on the lathe. Did you make a threaded mandrel mimicking the mill spindle to mount the part on when you machined the taper?

I dropped the spindle out of the machine and set it up in the lathe to machine the taper. I’ve obviously made a boo boo somewhere

 

[Seadog]

If it was clocked dead-on in the lathe, then i can only imagine that there is an issue with the register diameter. Did you confirm runout both on the OD as well as the ID of the spindle?

 

[Tinbasherdan]

If it was clocked dead-on in the lathe, then i can only imagine that there is an issue with the register diameter. Did you confirm runout both on the OD as well as the ID of the spindle?

I did, at least I thought I did! I’ve another chunk of steel, I’ll give it another go tomorrow and see if I can find out where I made the balls up. If not, it’s back to the drawing board. Ideally it’s a new spindle job really

 

[Tinbasherdan]

View attachment 318939
Why don't you make it like this instead?

That’s an option, although plenty for me to get wrong there!

 

[ukracer]

As I posted, I made an adaptor block for the spindle nose on the Taylor mill to take er40 collets. I’ll not lie, I’m not the greatest machinist in the world and so I’ve got about 12 thou runout of the cutter shank now.
It still quite happily cuts, although oversize to the cutter which in and of itself isn’t an enormous issue to be fair but what does the forum collective think

I am impressed you got one working. All the time I had it I never got round to making one.

Most of the stuff I do on the Bridgeport would be fine using that. I am a heathen anyway. I tend to expect the milling machine to take cuts like the lathe does.
It won't..

I would be interested in how accurate @doubleboost could make one in a Sunday nite nightcap.

 

[ukracer]

View attachment 318936

Original collets like this? is there provision (hole) for a drawbar to go through the spindle?

Yes that's them. But I tried and found none. A Bridgeport came up before I could get round to making a collet holder up.

 

[Brad93]

@Tinbasherdan

Right, so have you measured the runout with the spindle in the machine? I don't want to teach you to suck eggs I just need to see where you're at.

That's the first job. Get the original spindle running bang on in the machine. You should have literally no runout.
If you do then the bearings are shot. You can inspect the spindle out of the machine in a set of bench centres or balancing rolls.

You need to ensure that the spindle is running true at the top bearing journal and at the bottom bearing journal which is likely to be a pair of angular contacts opposed.

Once that is all verified, check the runout of your threads on the spindle (using a flat disc Stylus on the indicator) and the shoulder that your collet chuck is going to seat against.

This will validate the spindle.

Moving over to the collet chuck body.

I would turn an OD just so it's true, then cut your shoulder and your threads. Leave the stock over length.

Mount the 'collet chuck' to your mill. Inspect the OD for runout. You're really looking for zero. If you can't get the OD running right there is no point going further boring out a taper for the ER40 collets

 

[Kram]

What fit did you cut the register into the body? It will need to be a tight exact fit within 0.005mm or better as you have no adjustment using a one peice threaded body.

If you want adjustment and an easier job making it, you could make a threaded plate to go on the spindle, with 3 tapped holes for the chuck to attach. Cut the register slightly loose - that will allow you to clock it in then tighten up the bolts.