ER32 Collet Chuck for Proxxon PD 400

[EdK]

Wong,

With a tip of that large a radius the angle is not going to matter too much.

Ed

[Wongster]

Nothing much to show lately as I haven't have much time in the shop. This morning, I spent about an hour continuing where I left off. From 90mm dia, I managed to get it down to 76mm. Took me about 1.5 hours with some calls in between from my clients.

In the session, I replace the Sherline insert tool with the Proxxon HSS roughing tool. It was till at an angle so that I do not have too much unintended chamfer on the shoulder. The slight slope will be squared off later when I reach the desired 50mm dia for the boss.

I found that I'm able to cut deeper with this tool without the strange sound I heard earlier. But I stayed on at 0.5mm doc (1mm off dia each pass). Also, I was turning by hand using the saddle handwheel. This allows me the control over the feed. Like what was suggested, finishing is not critical at this point. Using the power feed, I have the problem of long stringy swarf bundling together. I've to stop several times each pass to remove them. By hand, the swarf just broke off when I ease off the feed. Closer to the shoulder, I would just wind back the saddle to remove them.

This is the angle I set for the HSS roughing tool:



This is where I am at:



I may have an hour later to do some work. Hope to finish off the boss today.

May I ask, should I start drilling and boring the centre hole after roughing out the boss or it should be done after I flip the stock over to clean out the other side?

Regards,
Wong

[DaveH]

Wong,

Just think after this you will be an expert on turning steel

Like they say "practise makes perfect" and here is your chance to practise a little using that HSS cutter. Try different angles -see and hear what happens

I would leave the drilling and boring 'til last but this is just a personal choice.

After you have turned the nose down and flipped it around, you will need to know how you are going to "measure" the register.


DaveH

[Wongster]

Thanks Dave, but expert I'm not and will not be.

I thought about how I should measure the register. My plan is to have the centre hole done after cleaning up the other side. From the hole, I'll face outwards and stop to measure with the caliper. Once I established where I'm on the 70mm dia recess, I can continue to open up the recess using the dial on the handwheel.

Is that the right way?

Regards,
Wong

[DaveH]

Wong,

This register is the most important part of the Collet Chuck. When the register is done it should just allow the Collet Chuck to go on the lathe spindle plate, and only just go on - with no "play". This will allow you to take the Collet Chuck off the lathe and to put it back on without any loss of accuracy.
Measuring a 'large' (small step) internal diameter with callipers with the accuracy required is damn near impossible. This is not a reflection on you, your ability or the callipers, it is just the way it is.

I think we need a more accurate way to do it.
What is really required some way to try the fit.

DaveH

[Wongster]

Dave,

A cylinder block turned to 70mm as a gauge helps? Like the dummy nose you did? I'm thinking aluminium as it is easier and faster to machine. Will it do?

Regards,
Wong

[DaveH]

Wong,

Perfect

DaveH

[Wongster]

Dave,

Should the aluminium gauge be a little smaller than 70mm to fit? How much smaller should it be?

Regards,
Wong

[DaveH]

Wong,

One makes the aluminium gauge to fit your chucks, again so that it just (and only just) goes into the chucks, a bit of oil, nice and clean, you may have to turn it a little to get it to go in.
Then you have a means to "measure" any register you wish to make in the future.
I know it is a bit long "winded" but for us in a home workshop, one of the "best" ways.
You will be making a precision and very accurate register gauge, just because we can't always measure it does not mean it is not accurate, so after you have made it keep it safe.

DaveH

[Wongster]

Roger that, Dave.

Silly me for not thinking of using my other chuck to test the gauge. I've just ordered a 4 jaw automatic chuck from Proxxon. Placed the order after confirming that it's going to be a Rohm chuck and opens to about 100mm. I wonder how many version they have as a follower of my blog told me he received a Proxxon brand 3 jaw chuck with his lathe. Mine is a Rohm. The 4 jaw independent, unfortunately, is brand Proxxon and is definitely not German made. Heard that they took some of their chuck from India.

Regards,
Wong