ER32 Collet Chuck for Proxxon PD 400

[Wongster]

Another short session today of about an hour to an hour and a half. The nose is now down to slightly below 50mm in diameter after "smoothening" out the surface. The spindle was bumped up to 660 rpm with very light cut using the Sherline's carbide insert tool. The tip on this tool has radius of 0.4mm. The result was great! The flange was also squared up and finished with the same method. I realised that I've to lock down the carriage to produce a decent finish when face turning. Also, I discovered that having a small relief angle between the edge of the insert and the work helps in the finish.

Facing the flange



The surfaces are rather smooth to touch, despite the looks. I didn't bother to sand down the surface.



From another angle. Should have also smoothen out the face of the nose, just for the fun of it.



Flipping it around in the 3 jaw chuck. I wanted to see if the jaws give enough clearance for drilling and boring the centre hole. Changed my mind doing the bore at this stage.



I left slightly smaller than 50mm in diameter on the nose after discussing this with GeneK. The idea is to finished up the recess and mounting holes first, mount it on the spindle flange, and turn the nose true to the setup. I'm hoping that I've left enough "meat" for the purpose.

Wanted to make the gauge Dave pointed out but the biggest piece of aluminium stock is a tad too small and I'm not prepared to turn down a piece of rectangular aluminium stock for this. I'll be visiting the metal shop, hopefully this coming week, to buy the required. At the same time, will be getting a thicker piece of mild steel stock to make this chuck as the material left for the flange seems a bit on the thin side.

Few questions:
1) Should I be boring the centre hole and turn the taper before threading?
2) On the mounting holes, I was planning to follow the article posted on the 7x12minilathe to mark the hole positions till I saw an article on Tool and Mods http://www.toolsandmods.com/mini-lathe-c...plate.html The author scribed the PCD of the mounting holes on the lathe after indexing the tool to the centre line. I don't really understand how he did the indexing and dropped him an email yesterday, hoping that he will reply. Any other methods available to do this?
3) On the mounting holes again, should I go with 3 holes or 4?

Regards,
Wong