[Jeroen]

Originally Posted by Thad E Ginathom

The chuck does not screw onto the spindle. Right?

No! Bolted down!

I just checked as I don’t think I ever ran it in reverse.

Mine has simple controls, variable RPM by means of a simple potentio meter and a three position switch reverse/off/forward.

Switching between reverse and forward gives a very noticeable difference in RPM. Much slower in reverse. Wonder why?

Jeroen

[Sutripta]

Originally Posted by Jeroen

No! Bolted down!

The chuck is bolted to the backing/ holding plate. How is that plate attached to the spindle?

Sutripta

[Jeroen]

Originally Posted by Sutripta

The chuck is bolted to the backing/ holding plate. How is that plate attached to the spindle?

Good point! Had not thought that through. But all my mates on the Dutch model building forum advised me a very strong terms not to give it a try. Especially not on a little hobby lathe like mine. Of course, all the various forces that you will create by reversing/having the blade upside down are opposite of what the lathe is designed for. So in the end I decided not to risk it.

Swapped the cylinder over and had a go at it, the conventional way. Got the RPMs up even a few more notches. Going pretty good!



A bit more tidying up with some very grit sandpaper and some very small, narrow files:



The cylinder on its support:



Turning this cast iron is very messy business. I was wearing a mask for all the dust. It gets everywhere:



I won’t be able to do much for Debbie the coming week. Getting the Spider ready and we will be out for almost a week.

So I made sure I cleaned everything very thoroughly:



Cleaned and oiled the lathe, cleaned the worksurfaces, oiled them too (WD40!), mopped the floor.





I like everything neat and tidy for the next job!

Jeroen

[Thad E Ginathom]

There's a file manufacturer in Italy that represent themselves as being as good as Swiss, but cheaper. Have you heard of them? Corradi Shop. They seem to make every conceivable file or rasp, and may that I never conceived of.

If I lived in Europe, I could probably spend a lot of money on their site. Yes, I like files

Edit: that's for USA. Maybe see here for Europe. They seem to be distributors for a heap of stuff.

[Jeroen]

Originally Posted by Thad E Ginathom

There's a file manufacturer in Italy that represent themselves as being as good as Swiss, but cheaper. Have you heard of them?

No, I had not heard of them before. I looked around the website. Some really nice stuff. I could do with some proper files. HBM doesn’t have anything like this. Somehow files seem to be a bit underrated in hardware shops these days.

I do prefer proper wooden handles to the plastic ones though.

Jeroen

[Thad E Ginathom]

I think I've only seen files with handles in the DIY-shop ranges. Engineer/etc stuff comes bare-tanged (and I admit that I have not always fitted a handle).

These files, which I posted in the DIY thread back then, are Vallorbe, and were rather expensive

They may look like needle files, but they are not: for scale, overall length is 210mm. I was happy to see that Stefan Gotteswinter has the same set. He has modified the inbuilt needle-file-style handle by adding shrink-fit tubing.

A while back, I took my used-used file, which seemed to be worn out, and soaked it in vinegar for a couple of days. It came out sharp and fresh! And there was a lot of crud left in the vinegar.

[Jeroen]

Back behind the lathe/mill after our holiday! So tonight I had a go at milling the exhaust port on the cylinder.

Challenge one, setting it up in the mill. My vice is too small, so I had to improvise. I also was cautious not to damage the outside of the cylinder. So just some 4x folded paper as a little protection.



Going well. My little mill did remarkably well, much better finish on parallel passes than before. Not sure why, same bit, same RPM, different material though, cast iron? Also, I am feeding quite slowly with very small cuts, about 0,2mm. I am not that confident of the improvised clamp down. Taking it nice and slow, with as little forces as possible.



In the end it worked out really well. Sorry, forgot to clean properly, but it looks good and it is pretty good measurement wise too!





Jeroen

[Thad E Ginathom]

Very good!

I guess that looked and felt firm, but I'm nervous. and I would have wanted something that prevented it flying at me if it was let go. Something at the back would be nice too. A picture of a V block is forming in my mind!

[Sutripta]

^^^
The TSlot groove is taking the place of the V Block. Certainly not ideal, but workable, with some caveats. Otherwise cylindrical objects between straight parallel faces is a recipe for trouble.

Sutripta

[Thad E Ginathom]

Originally Posted by Sutripta

The TSlot groove is taking the place of the V Block.

I did notice that. It gives three points of contact, which is a start. Without that, a sneeze would move the thing!

[Jeroen]

Last night I continued with the last tricky part of machining the cilinder. The entrance for the injection gas mix.

Had to be machined under a 70o angle.



With no other means or options available to me, I swivelled the mini mill head in position once again. I dialled in the angle on the little scale on the mini mill head. Next I checked visually with a protractor. I checked all measurements afterwards and everything came out good!



I had to be very careful for clearance of the various bits of the drill as well as not hitting the cool rib. For additional safety I had also put a bolt in the T groove, locked with two nuts. It is not ideal, but it is the only option I have until I get myself a bigger machine clamp.My little poxy proxxon clamp won’t hold the 50mm diameter of the cylinder.



I am taking very slow 0,2mm passes, so the forces on the cylinder are not that huge. Took about an hour. End results look pretty good. Even though you can see a line between the two passes, you can’t feel a thing. Not with a nail or your finger. So pretty smooth surface.



With the mini mill all set up I also drilled the holes. I took the right clamp of to measure and mark the exact spot. Auto Centre punch to the rescue!

Centre drill first, obviously.



Next a 3,5mm all the way through.
Next up to 5mm for the M6 thread, 8mm depth. I still need to tap the thread



Pretty pleased with the result:







I still need to drill a bunch of holes and some thread to be tapped too. I won’t start with that until a have the various other parts ready so I can align the holes on both parts precisely and easily.

I also need to drill the intake port. Once that is done, and all the other holes drilled/tapped I will hone the cylinder again, before starting on the piston.

I aim to visit HBM this Saturday and get myself a larger machine clamp.

Jeroen

[Thad E Ginathom]

Super, Jeroen, well done!

[Sutripta]

Originally Posted by Jeroen

For additional safety I had also put a bolt in the T groove, locked with two nuts.

Attachment 2044932

I am taking very slow 0,2mm passes, so the forces on the cylinder are not that huge. Took about an hour. End results look pretty good. Even though you can see a line between the two passes, you can’t feel a thing. Not with a nail or your finger. So pretty smooth surface.

Good call on the longitudinal stopper.

And job well done, esp. given the resources at hand.

Sutripta

[Thad E Ginathom]

I mentioned watching Adam Booth on Youtube taking half an inch off a block of steel... with a K&T mill that must weigh a ton or two. But heck, this and more, is what the machine was designed and built to do. Not to mention a lifetime of every-day machining experience and a workshop full of three generations' collection of tools.

Hats off to Jeroen and the humble Proxxon!

[Jeroen]

Originally Posted by Sutripta

job well done, esp. given the resources at hand.

Originally Posted by Thad E Ginathom

I mentioned watching Adam Booth on Youtube taking half an inch off a block of steel... with a K&T mill that must weigh a ton or two. But heck, this and more, is what the machine was designed and built to do. Not to mention a lifetime of every-day machining experience and a workshop full of three generations' collection of tools.

Hats off to Jeroen and the humble Proxxon!

Being able to make do with what you have is a good approach for anything in live! As a former merchant navy engineer it was important too.

Even so, I have come across a couple of youtube video where this little Proxxon does pretty good. I can’t understand what is said or written, but have a look at this:

https://www.youtube.com/watch?v=SAiPlkvQD9o&t=452s

https://www.youtube.com/watch?v=vgfaDfjbu4w

This does look encouraging for when I start machining the supports from Aluminium! I might want to practice a bit more though

But it is really slow going! To a certain degree that is also true of the lathe. But again, I never bought these machines with this sort of work in mind. If I ever upgrade, I do know much better what to look for.

Just soldiering on and very much enjoying it. Thanks for all the encouragement.

Jeroen