Sunday, September 5, 2010

My attempt in making tool holders for A2Z QCTP - Failed Attempt

The session I had ended badly.  I was drilling the 4mm hole on the lathe for the tiny boring bar to find that the hole wasn't parallel to the body of the tool holder when the drill exited the opposite side.  I told myself it is alright as I still have the use of one side and that the QCTP can be adjusted to the angle I need before fastening it down to the cross feed table.

With that in mind, I proceeded with the drilling of the cross hole to accept a 10-32 screw to hold the boring bar.  As usual, I started with a centre drill before introducing the 4mm twist drill.  The only different this time was, the hole locations were centre punched.  The tip of the centre drill snapped off as soon as I bring down the spindle. I went on to do flip the 2 ended centre drill around and tried again - the other tip also snapped off.  But this time, I get to see what happened; I wasn't in total alignment with the punch marks with the tip of the centre drill.

To try saving my work, I relocate the holes and push through using the 4mm twist drill without any centre drilling or punch mark.  It went on well.

Though I've not completed the single trial piece of the tool holder, I've learned a few things:

1) Assuming my mill was properly trammed, to square the vise to the mill, I need to also indicate the bottom of the vise and not just the clamping face of the fixed jaw.
2) Don't centre punch when I am using the centre drill unless I'm sure that the spindle is lined up to the hole.
3) If I've no confident in drilling parallel to the work piece on the lathe with the workpiece fastened to the cross slide, use the mill or drill press after marking the hole location.
4) Reduce the width of the slot for dovetailing.  I'll have a firmer grip on the QCTP.

Thank God that I decided to cut out a small piece from the stock to test this out.  Though milling the slot and the dovetail took quite a while to complete, I don't end up with the whole batch going into waste.

Some pics:

The tiny boring bar not being aligned to the body of the tool holder.

Note the dimple above the cap screw. There is a tip of the centre drill inside.  Cap Screw for test only. I've not gotten the set screw yet.

The other end of the mounting hole is too close to the edge.  I drilled through so that I can use the 2 sides.  Should have just drill the 2 holes individually.

My new toy: Proxxon Parallels.  They're out by only 0.0005mm!  Fantastic for the price I paid - S$180++!!!

This set was bought from Mike of  My machines and accessories were from him too.  Nice chap to work with.

I'm going back to tramming my mill again in my next session in a week or 2.  Some company event next weekend.  The vise will be indicated in properly this time.  No more excuse not to get this right.

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