Half size Stuart 10 V.

[Chipswitheverything]

Those very small turning and boring tools are really rather nice!, Ti nitride finish?, and with coolant channels for CNC use?   This small engine project is an excellent one; as Jason said, the No 10 engines don't really scale up effectively, but scaled down will be fine.  Dave

[pirmin]

for anyone who dont know these Boring tools, they go under the name of PH  Horn ( Paul Horn ) from germany. the Sytem Mini 105 and Supermini 105 is their most known System of small Boring and grovving tools...allthough expensivve for the home shop you can often find good deals on ebay ( Horn 105 as s searchword for example )

i was lucky and bought 125 pieces for 1 $ per piece, all used in industry but none of them had a bad performance, and with a good diamond cup wheel u can easily regrind them....the trepanning tools are also quite handy some times !

[Jasonb]

You can also get some quite usable ones cheaply from Aliexpress and they have easier to hold shanks. Just put "micro boring" into their search box

[Michael S.]

Thanks for the information. I have ordered carbide cutters from Ali Express before and they are good.

I already know that I need smaller screws and nuts. Smaller than M2.
You have already written in other posts that you order model building screws from a German supplier. Which company was that? I've always bought my screws at exhibitions and that was a long time ago.

Michael

[Jasonb]

I use GHW who do the smaller size hex
https://ghw-modellbau.de/Home

And there is also knupfer who go down to M1.0
https://knupfer.info/shop/index.php/deutsch/

[Michael S.]

Thanks Jason, I'll take a look there.

Today I continued working on the cylinder. The cylinder has through holes and was then further machined in a vice.
The exhaust steam channel is 1.5 mm wide and the supply steam is 1.0 mm wide.
The hole between the slide and the cylinder was a bit difficult but with my clamping mandrel it worked well. There are still a few drillings that will have to wait for tomorrow.

Michael

[RReid]

Nice work, Michael. The Queen seems pleased.

[crueby]

Impressive  little engine!   

[Michael S.]

Today there was still time for the slide box and the cover.
I noticed afterwards that the M 2 threads and nuts were perhaps a bit too big. But now it is like this.

Michael

[crueby]

Beautiful!  Looks great next to its larger cousin.   

[Michael S.]

Thanks Chris. 

[10KPete]

That is a beautiful little bit of work. Excellent engine!

[Jasonb]

If the look of those M2 fixings looks too big to you then all is not lost.

Make some studs that are M2 where they go into the casting and have them 2mm dia through the parts they retain. But on the other end reduce the diameter and thread to a smaller size. M1.2 would be half size but you might get away with M1.4 or Even M1.6

Although I seldom add all the fixings to my 3D CAD models I do have a file where I have ready to use nuts on studs which can be added to an assembly simply to check that the nut can turn and that it looks right.

I'd draw it for you but you have different stud positions than the Stuart drawings which are uneven, let me know what you have and I'll show it with some size options.

[Michael S.]

Yes, the cylinder cover only has 4 screws instead of 5. I first followed the video that I mentioned at the beginning of the post. The 10 is also simplified there.
Your idea with the reduced thread at the end of the bolt is great. Maybe it's enough to make the tall M 2 nuts a little flatter.
Thanks for your offer. I won't be at home or in the workshop for the next 4 days.
I've also noticed that the 4 M2 nuts on the stand for screwing to the base are definitely too big. But I can still change that.

Michael

[Michael S.]

So in principle I would continue to stick to your blueprint. There are still a few thread sizes that practically have to be designed so that it works. For example, the connecting rod screws the screw through the crosshead.
I used M 4 x 0.5 as the supply steam line and exhaust. Could have been a little smaller.
I notice that I am missing many small thread tools under M 2 (M 1.6, M1.2)
I have to make an order.

Michael