mills 1.3cc diesel mikes-models

22nd and 23rd February 2008 session 10

Well today (23/02/2008) was much better than yesterday’s efforts. I gave up
trying to do anything critical then because it was just one of those days! I
decided to practice on a spare piece of aluminium and bore it out, then cut the
threads, because I am nervous of wiping out the work on the good crankcase.
Seemed a simple idea but there was no way I could achieve any sort of quality
finish in the cutting of the bore. I tried differing tools with no luck and I was
starting to question whether the aluminium may be the problem. I then decided
to stop the practice and make my own boring bar , which would allow me to
sharpen my own tooling. For while I am a novice, I seem to have the knack or
producing good cutting edges on tool steel.

How come, you may ask? The answer is the video by Jose F. Rodriguez on
grinding tool steel. I have found this particular DVD to be excellent investment.
Jose shows you how to grind the tools in a simple and uncomplicated way. I
believe if it wasn’t for this particular video, I would have spent many pounds on
buying ready made tooling. Indeed I have yet to find any cutting tool of a
‘reasonable’ price that would match the results I get myself. I would certainly
recommend this DVD to any other novice, or even any model engineer who
buy’s, rather than grinds their own tools.

I made the boring bar by drilling a 1/8”th hole at 45° in a piece of stainless steel
bar and at 90° to that hole I drilled another to intersect the first. Then I tapped
that hole for a 4mm grub screw. I then ground two angles on a piece of 1/8”
square tool steel as described in one of my reference books, and turned down
the other end to match one of the tool holders I made for the new lathe.

Today (Saturday 23rd February 2008) I completed the boring bar ( photo 1 on
the right) and was very pleased when trying it out on the aluminium blank in the
4 jaw chuck. It was as different from yesterday’s efforts as chalk and cheese!
So there is nothing wrong with the aluminium and I now have another tool that
hopefully will last for years.

Tomorrow I will be able to ‘try again’ and practice on another piece of
aluminium, in preparation for the crankcase proper. Who knows I may even
tackle the crankcase proper!

The rest of my workshop session was spent dealing with the Myford ML7
refurbishment.

Time spent today 3 hours. Total to date 19 hours. 00 minutes.