A PM RESEARCH MODEL STEAM ENGINE - PART #2 - IN THE WORKSHOP

[@steamboatmodel]

If you do not practice with scraps when using a belt sander you will soon have lots of scrap to practice with. A belt sander can produce scrap almost as fast as a CNC machine.

[@SteamCoal]

excellent

[@Gopherdave1]

Thanks for this series, I'm just about to start mine!

[@keithappleton]

Have fun!

[@rebelelectrons1803]

I have a PM #3 casting kit on my bench right now. You can get it as aluminum castings or cast iron and bronze - I got the cast iron and bronze version. I agree it's a nice kit for the money.

[@colinbowler1104]

Very timely, I’ve just received my unmachined castings kit from PMR in the mail. I think I’ll wait and see what not to do with the flywheel before I start the build since this is my first time working with castings. I’ve subscribed to your channel Keith and look forward to more videos. Cheers, Cole

[@lynwoodreed9032]

I really like this video. I have the same engine but I painted it dark green. I find it a well running engine on relatively low pressure. I will say that the castings in my engine were a lot cleaner than those pictured here.

[@jamesoates1334]

Slot head screws, are the makers catering for buyers with minimal tools?

[@CraigLYoung]

Thanks for sharing 👍

[@keithappleton]

Thanks for watching . . .

[@Jims-Workshop]

Keith, 1/8th Whitworth is almost exactly the same as 5-40 as supplied by PM research. The main difference is that Whitworth has a thread angle of 55 degrees and 5-40 UNC is 60 degrees. both are 40 threads per inch. Both are close to .125 in diameter.

[@tonywilson4713]

I am fairly certain you are right but the other screw that is also right in that size range is the UNC 4-40. I used to do model aircraft and that was what the American kits all used as opposed to the 1/8 BSW. Without measuring the screw OD they might be quite difficult to distinguish by eye.

[@ilfarmboy]

thank you for your help(you must have a feather touch don't you?)

[@TestECull]

This is making me want to pick up a PMR #3 myself. Looks like an excellent little engine and, if I'm brutally honest, a better design than the Stuart 5H I already have.

[@liamroggenkamp]

They are great little engines. I really enjoy mine. Pretty well priced too

[@godfreypoon5148]

I have a belt sander, but I've never needed to use it because all of my belts are already smooth enough. In fact, if they were any smoother my trousers would probably fall down.

[@keithappleton]

}:-)))

[@treavy1]

question keith is it really expensive when even buying a begginer live steam trail or live steam engine i have one my grandfather gave me its stationary but is it really a hard hobby for newbies

[@keithappleton]

It depends on to which level that you want to take it. The Mamod and Wilesco type steam toys are not really very expensive and it's a good place to start.

[@dougschutz616]

Pretty sure the screws are 5-40. That's what is called on most of their unmachined kits.

[@sfeddie1]

You’re probably right about the 5-40 threads because it seems you have done some research. I remember that back in the heyday of slot cars the 1/8” axles had 5-40 treads. To me these screws look a bit bigger than 1/8”. In any case I agree with Keith. These cheese head slotted screws look all wrong on this engine. I think all slotted screws should be banned. Maybe Phillips too. Old technology. Let’s all switch to square head, Torx, or Allen head for everything.

[@misterflibble6601]

For those in the UK who might not know that's #5 (small screw diameters in the U.S. use numbers) 40 threads per inch

[@tonywilson4713]

I am fairly certain you are right but the other screw that is also right in that size range is the UNC 4-40. I used to do model aircraft and that was what the American kits all used as opposed to the 1/8 BSW. Without measuring the screw OD they might be quite difficult to distinguish by eye.

[@gottfriedschuss5999]

Doug, Of course, you are correct. I wanted to comment, that, by definition, a 5-40 screw has a major diameter of _exactly_ 0.125" = 1/8" (yes, of course, there are tolerance allowances, blah, blah, blah...). The screws in this series increase (decrease) in size linearly. Each unit increase in screw diameter (e.g., from 4-40 to 5-40) is an increase of 0.013" in major diameter. If one remembers these two pieces of information, then you can construct a table of major diameters without a reference book: Major Screw Diameter Inch mm 0000-160 0.021 0.5334 (very expensive!, when you can find them) 000-120 0.034 0.8636 (expensive) 00-96 0.047 1.1938 (not cheap) 0-80 0.060 1.5240 (these, and larger screws, tend to be commodity items) 1-64 0.073 1.8542 2-56 0.086 2.1844 3-48 0.099 2.4750 4-40 0.112 2.8448 5-40 0.125 3.2512 (exactly 1/8" major diameter) 6-32 0.138 3.5052 8-32 0.164 4.1656 10-24 0.190 4.8260 12-24 0.216 5.4864 14-20 0.242 6.1468 (uncommon, because it is very nearly the same as a 1/4"-20, 0.250"-20) Notice that all the screws from 6-32 and smaller differ by 0.013" major diameter from one size to the next. And, the screws from 6-32 and larger differ by two screw sizes, and the major diameter is 2x0.013 = 0.026" from one screw size to the next. The number after the screw number is the number of threads per inch, tpi. For reference, 24 tpi is very nearly the same as 1 mm pitch, 48 tpi is very nearly 0.5 mm pitch, and likewise, 96 tpi is very nearly 0.25 mm pitch. All three of these approximations are in error by about 5.8%, e.g., 24 tpi is actually 1.058333... mm pitch. All the US customary number screws have a 60º thread. Personally, I prefer screw sizes to increase (decrease) geometrically rather than linearly (as do the US number screws). BA screws increase geometrically. They average 12% smaller than the previous size, rounded to the nearest 0.1 mm. That is, start with a 0 BA screw, which is 6 mm diameter. 6x0.88 = 5.28, where a #1 BA screw is actually 5.3 mm. 5.3x0.88 = 4.7 mm. Rinse and repeat, and you get that a #16 BA screw is 0.79 mm. The thread _pitch_ for BA screws follows a similar geometric progression. BA screws are 47.5º vs. 60º US number screws. By coincidence, a #5 BA screw has a major diameter of 0.1260" and a thread pitch of 43 threads per inch. These numbers are close enough that a loose tolerance 5 BA screw will, in most cases, screw into a 5-40 nut and vice versa. If the nut is particularly thick, or one is trying to screw a stud into a deep(ish) hole, there will likely be interference. I hope this helps other readers. Be well & Best regards, Gottfried

[@PaulSteMarie]

Be careful with the BA taps. 5-40 UNC screws have 60° threads, not 47°.

[@bullettube9863]

I'm assuming your dinner came out okay?

[@keithappleton]

Yes it did }:-)))