Tiny Power M Twin Build

[racerfrank]

First off I would like to thank everyone for the compliments, if I have missed thanking someone, consider yourself thanked.

Well I was at it again today 6 hours and 45 minutes worth and this is what I got accomplished. ONE!!! valve face finished. Now to be fair I had one phone call and ate the sandwich I took with me. I also spent some time doing some math and some time just thinking.

All of my dimensions are within a few thousandths and I had to work with What I think was "core shift".

Here are a few photos.

[DetroiTug]

Looks good, Frank.

What I like to do at that point to establish a flat surface, short of a surface grinder, is hit the face with a pink boatstone and oil. It will seat the valves much faster.

To each his own and I'm not trying to tell anyone how to do anything, just throwing it out there.

-Ron

[Lopez Mike]

Good idea about the stone. Wash it off when you are done of course.

I put a sheet of 400 grit wet or dry sand paper on some trusted surface, in my case, my band saw table, and work it flat with some oil.

[racerfrank]

I was planning on stoning or using a fine grit paper on a flat surface. I've never heard the term "boatstone" before. I have a few 5" 0r 6" long honing stones. They are the type for sharpening knives, I'm assuming these would work. I have also seen some use of fine paper wrapped around a block of flat ground steel like a parallel bar or a 123 block any pro's or cons to that method?

Frank

[DetroiTug]

Yeah, just a long stone of some type. The boatstones are longer and a bit wider to stay flat while using. They are good for flattening a mill table of dings etc.



That is going to be a fine engine when you're finished.

-Ron

[racerfrank]

I put in a few hours on the M tonight. both valve faces are done and while the cylinder was set true I use an end mill over the side of the face to clean up the area where the exhaust flange bolts on .


Started on the steam chest got it to inside and outside dimensions and then started on drilling the holes when the forward/reverse switch on the mill broke, so Ill have to fix that tomorrow.(the boss will like that)


Does any one( Ron I'm looking your way) see a problem with bringing the steam inlet in on the side of the steam chest(area where the blue cap is)instead of on top? It would be above the exhaust by an inch and a half or so.


Until next time Frank

[DetroiTug]

Frank,

Sure, the steam inlet can be brought in there, no problem. I wish I had, those steam pipes are unsightly up there. It could be brought in anywhere and it will be just fine - even the bottom or the through the valve chest cover. There is really no wrong way to do it, it's just aesthetics.

Then what I would do and the reason I wish I had, is where they show the line coming in on the print, I would make a nice bronze round-topped guide for an extended valve rod. You can drop the rod diameter to .312" and you'll be able to get a 3/8-16 or 24 die over it to thread. Much better set up for the valve, it's a bit hobbyish the way it is. And it will look better.

-Ron

"the forward/reverse switch on the mill broke, so Ill have to fix that tomorrow.(the boss will like that)" That's the trouble with that "Government work"

[racerfrank]

A few more photos. I did the second steam chest today. It's starting to look like an engine.


Put bolts in the four corners then used a fifth to make sure all 12 would go in, and they do.


The red dots are where I am thinking of bringing the steam lines in. I will trim the steam chest when I set up to drill and tap the top cylinder head.


Frank

[mtnman]

Should there be Aligning Pins to hold the steam chest from movement?

[racerfrank]

Should there be Aligning Pins to hold the steam chest from movement?

There aren't any shown on the drawing. The cylinder block was drilled and tapped for 3/8 bolts and the holes in the steam chest are drilled 3/8 and are very snug on the unthreaded portion of the bolt. I don't think there will be any movement.

Frank