Absolutely chuffed to bits!!

[websterz]

Today I cut my very first metric single point thread!   

I have been working a 3 3/4" diameter lump of mystery steel down into the shape of an ER32 collet chuck for my 7x12 for the past several days. Today I finished turning the collet boss to diameter (40 mm or 1.575 for us Colonial types) and single pointed a lovely 1.5mm thread for the closer nut. Considering my lathe is Imperial I was a bit nervous about cutting metric threads on it. I was worried about nothing as it turns out! By a stroke of good fortune my new control board does not require that the speed be set to zero before reversing the motor. So it was a simple matter of one hand on the F/R switch and one on the compound. Back and forth, pretty as you please, until I had about 2 full threads engaging on the nut. Then I switched over to a double cut 3 corner file and dressed the thread until I had a very snug fit. A quick polish with 200 grit emery to clean up the ragged crown and the nut spins on and off like silk. Here's a video of the final result. (Sorry about the loud radio in the background)

http://vid797.photobucket.com/albums/yy258/websterzdesign/er32chuck.mp4

[Bogstandard]

Websterz,

Congratulations, another string to your bow.

Isn't it nice when you discover how to do something that has previously eluded you?

Sorry I couldn't watch the vid, but I won't allow Quicktime anywhere near my computer, but I am sure you are well proud of your achievement. As you should be.


Bogs

[websterz]

Thanks John, I feel like one of the guys now! 

I just came in from the shop for a bite to eat. This morning I set up for cutting the 8* taper and finished the lathe portion of the collet chuck project. I had about .003" of non-repeatable TIR according to my Starrett Last Word DTI. I am chalking that up to a bit of a rough job boring the taper. I will spend some time with my cratex sticks and hone the bore down and I imagine the runout will drop dramatically. Now I have to pull the chuck and set it up on the mill to drill tommy bar holes and d/t set screw holes for dialing out the runout (if there is any left). I recessed the back of the chuck and left a 3/8" thick lip that extends over the spindle face. It will act like a Set-Tru chuck and allow me to dial the chuck in dead nuts. I know there wiill be no error in the collets as they are top o' the line Parlec brand. I was going to buy the cheap Chinese stuff but I got these on the 'bay for a couple bucks more than the cheap stuff. I love it when a good bargain comes along!!

[DaveH]

Websterz,

Well done - give yourself a pat on the back

DaveH

[75Plus]

Websterz,

Well done - give yourself a pat on the back

DaveH

Hey!! A guy can break an arm that way! Let the rest of us do the patting. Congrats. Websterz

[websterz]

Websterz,

Congratulations, another string to your bow.

Isn't it nice when you discover how to do something that has previously eluded you?

Sorry I couldn't watch the vid, but I won't allow Quicktime anywhere near my computer, but I am sure you are well proud of your achievement. As you should be.


Bogs

Here are a couple of pics of the final product. I added the 4 set screw holes and numbered them for easy reference. I also added 2 tommy bar holes. Ignore the mess behind the lathe...I'll get to it later. Oh, a little trick for indexing the part on the mill for drilling holes. I mounted a 3/8" stud in the collet chuck with a square nut on the end of it, held solidly with a smaller jam nut to keep it tight. It was a simple matter of rotating the chuck in the vise in 90* increments and clamping down on the square nut for equally spaced holes. Why set up the rotab for six quick holes?



The bar is the one that came with my mill for locking the spindle during tool changes. I built a spring loaded one a long time back but kept the little Chinese persuasion bar...knew I'd find a use for it eventually! As luck would have it the spanner that came with the lathe for adjusting preload on the spindle bearings is also a perfect fit on the closer nut. My lucky day!

And yes, the power was OFF when I left the tools in the chuck for the pic. 

[Pete.]

Websterz,

Congratulations, another string to your bow.

Isn't it nice when you discover how to do something that has previously eluded you?

Sorry I couldn't watch the vid, but I won't allow Quicktime anywhere near my computer, but I am sure you are well proud of your achievement. As you should be.


Bogs

Vid is just an MP4 John - I right-clicked, save as and watched it with GOMplayer.

[doubleboost]

Well done
There is nothing like screw cutting to clear the mind
Total concentration is a relaxing thing
John

[websterz]

...Total concentration is a relaxing thing
John

Indeed it is. It is also a great way to speed up the clock. I put in 8 hours in my little playground today and it feels like half that.