Mini Kossel: Carriage Wheels

The trial in making the wheels started on Saturday and Sunday for a couple of hours each day.  Some pix were taken but I didn't have the time to update the blog till now.  Just returned from the A&E of Changi General Hospital which we spent the last 4 plus hours waiting for the doctor to administer treatment to my poor little Ruth.  Her fever went back up Monday night and she started bleeding from her left nose.  We panic and drove her straight to A&E after midnight.  The wait was rather long with more time spent waiting for the result of her blood test to be out.

Ruth is such a brave girl.  Despite the pain and discomfort, she allowed the doctor to draw blood from her without once pulling back her arm.  I'm so proud of her!

As I was to send our helper to the airport in about 2 hours time for her trip back to Myanmar, I gave up the idea of sleeping - and so this blog entry.

Terrace provided me with a length of delrin of about 28.6mm diameter.  I felt bad as it will be such a waste of the expensive plastic as the final diameter of the wheels will only be 15mm.  He explained that it was meant for another project of his which didn't happen and so using it for this purpose - felt so much better after learning this.

On with the pix.  

A short section was chopped off at the bandsaw and chucked into the lathe. Both ends were faced. As the material is softer than what I usually play with, I went straight with the 3/8" drill. It cut through like butter!

Next came boring to ID of 10mm to fit the bearings. I target at 9.95mm to press fit the 2 bears into it. I wanted to try using the boring head I bought from CTC Tools but the dial to adjust the boring head was facing the wrong side if I want the clamping capscrews to face up. I may have use the tool the wrong way. Will study it further.

Next I tried putting the boring tool on the QCTP Tool Holder. After setting the height, I find that I can fit it into the hole... Its too big...

Setting the face of the QCTP square to the faced workpiece.

I ended up using the micro tool bar my Irish friend bought on my behalf and shipped over. This little tool works very well but a tad too short for this job. So I've to go one wheel at a time.

Test fitting the bearing.

Working on the OD. I didn't expect myself to be able to hit 15mm exactly! At least that was what my 2 decimal places Mitutoyo Digital Caliper said.

Parting off with the insert tool.

After parting off.

After facing off the other side, the first bearing was fitted. I pressed it in simply using a 123 block. Easy job.

2nd bearing pressed in. To remove the bearings, I've to use a pin big enough so as not to damage the bearings to tap them out.

The next ops is to turn the chamfers on each side of the wheel so that it seats nicely in the slot of the aluminium extrusion.  The plan is to cut all the 18 pieces needed for the mini kossel and turn a shaft to hold them each at a time.  I've yet to think of how to turn the chamfers accurately for it to balance itself in the slot like the cross section pix below.

I'll figure that out when I feel better.  A little under the weather myself...

Be blessed!