Sunday, May 20, 2012

ER32 Collet Chuck - Test Fit

I was rather curious to find out if the recess fits the bore on the spindle flange. Went back to the shop and take everything off and fit the work.

It seems to fit nicely...

Pushing the flange of the chuck to be against the flange with one hand, I tried moving the chuck against the registration boss on the flange. I can feel slight movement and some knocking sound at certain point... boy am I disappointed...

I put on the 3 jaw chuck (without the bolts) and did the same. The slight movements and a little knocking sound was also there.

I measured the gauge with the caliper - 70.01mm.  The registration boss on the spindle flange measures 69.99mm.  That means that the recess is 0.02mm over sized...  No wonder the gauge fits so tightly into the recess of the 4 jaw chuck.  I've to press it in with my hands.  If the gauge is oversize, the recess will also be...

I'll push on till the end to complete this project.  The decision of making another piece will be left till the completed collet chuck is tested.


GeneK said...

Wong, I've been mulling this over for a while. Your error of 0.02mm isn't adding up in my mind. That is less than 1/10,000 of an inch. (Sorry that's what I grew up using, except when in college) So I think that if you are feeling some side shake there is more difference than that.
I don't trust digital calipers to be any closer than 2/1000 of an inch. Your measurements of 69.99mm and 70.01mm are at the extreme of your calipers sensitivity. In physics and chemistry we had to measure with tools that were ten time more sensitive that what we wanted to measure. I would use my 2-3" micrometer that reads to 1/10,000 of an inch to measure those hubs. While we are thinking, in the long run you may actually want more slop in the fitting. If it can move a little, you can loosen the screw and tap the collet chuck to center it like a set-tru chuck. Of course that would require aligning it every time it is installed. Just some thinking that I hope will help.


Wongster said...

The tapping of the collet chuck to centre it sounds like a good idea in this case.

The transfer screws have arrived, but sent to the post office for collection as there wasn't anyone at home to sign for it. I'll pick them up, together with the 3" angle plate on Monday. Got another full day duty tomorrow and the post office isn't open on Sunday.

Thanks for the comment; it does help.


GeneK said...

Wong if you do make another chuck just open up this one so it can be adjusted and use it for some of the special jobs that need a loving 'tap' to get things just right.