PMR Mill Engine.

[Tin Falcon]

An engine I have been wanting to complete for a long time is the PM research mill engine . I have the casting set ready to be machined the fly wheel is done I think I actually machined several and borrowed them.
And has been a while since I added a new engine to my display. So Friday night of Cabin fever I decided to treat myself and purchased a pre -machined kit.

Saturday morning I put it together with a few borrowed tools. and it was running on 10 psi of air by mid afternoon. I was in no hurry to finish it and I was talking to folks and people seemed to enjoy watching me assemble this thing. Dave encourages me to buy hex bolts for it and before I know it the doors close for the day. The engine happily chugs away on Sunday.
At some point my wife and creative consultant suggest a brick floor base for the new addition so ff to PMR for bricks.

After the show a little more tweaking and she runs on 3PSI I am much happier.

Today the brick work.
still need to clean it up a bit. but we like the look.



Tin

 

[jgedde]

Very nice Tin. Congrats! How about a video?

After Cabin Fever lasy year, I built the twin cylinder version of that engine from their unmachined kit. It's really a nice running engine as I'm sure yours is too!

What are the bricks made of?

John

 

[johnmcc69]

Beautiful engines gents! How are the plans/instructions? Easy to build & machine?
Good quality castings?

John

 

[Walsheng]

Tin: You must be in a time warp somewhere. The pictures are dated 2009!
I was looking at these on line and put one on my "TIWTD" (things I want to do) list.

John

 

[Tin Falcon]

The bricks are plastic from pm research a sheet of brick and a pack of brick corners glued to a block of marine starboard plastic. the mortar is latex caulk.

They are 1/12 doll house scale so any store that carries doll house supplies should have there own version.

PM research is a small USA company . And as they machine the castings as well as making and selling them I cant see them allowing poor casting through to the customer. As well as purchasing kits several other of my engines use there fly wheels.

The drawings are well done and professional looking.

the machinist kit comes with a c size 17 x 22 parts drawing and an A size 8.5 x 11 exploded view.

the pre machined kit has a b size exploded view with a parts list.

The tolerance on the pre machined kit are tight and there is some deburing that needs to happen . i did have to coax a couple parts together.
Tin

 

[Tin Falcon]

A little update . In the photo i had not mounted the engine to the base yet as I wanted to run the ends of the base against the belt sander . I also had not decided what to use to hold down the the engine. I looked through my supplies and did not find anything I really liked. but I do like the look of the 5-40 hex head bolts I used to hold the heads on .
And experience has shown be that some plastics hold a pretty good thread on machine screws without tapping just form the thread with the screw.
So I looked up the tap drill size for 5-40 picked one size bigger and drilled away the screws went in nicely and seem to be holding well.
Tin

 

[johnmcc69]

Got me thinking Tin, "formed" threads are stronger than cut threads aren't they?
When I worked in a shop that worked allot with die castings, we used "roll" taps.

John

 

[ChooChooMike]

I did something similar. I bought a PMR 3BI (bronze/iron) horizontal mill engine machined kit from one of the vendors at NAMES in 2007. It sat on the shelf till last year (2012) when I needed some incentive to get back to engine making. So I dusted off the box and started assembling the kit. Took a while to get going due to frustration with the piston/rod/crosshead binding and some related issues. I put it aside a number of times. Finally after 6 mos of putting it aside too many times, I figured out the machined crosshead slide was out of tolerance and was causing the piston rod to be off-center. I made a new part and the binding finally vanished. Timed the engine and it ran the 1st time - yeah !! Ran it for a couple of hours with plenty of oil on my paintbrush compressor to break it in. Now it'll run very quick and nicely off a can of compressed air (e.g. used for dusting off stuff).

Now that I have a working model I can use that as a template for building the unmachined version

Also assembling a Graham TVR1 2-cylinder steam engine as even more incentive to get back to machining !!

Mike

 

[drgear]

I am a new member and am going to start my first engine which is this pmr in the unmachined version . I have been looking at the drawings and some of the parts look like it could be a little challenging

 

[Tin Falcon]

The PMR egines are marketed as beginner engines. the first engine i started was the 2b. I broke off a tap in the head and it ended up sitting for 3 years in the mean time I completed a couple of bar stock engines.

It takes time to learn set ups and work holding. sometimes it is easier to hold a larger piece and machine what you need off the end.
Tin