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From Plans / Re: Muncaster Grasshopper - Work in Progress
« Last post by kvom on Today at 09:36:22 PM »
My piece of tube from Bailey arrives this afternoon, so I was able to take the first baby steps in this project.  Here's the raw tube as shipped:

I cut off ~ 5.25" with the bandsaw, then  mounted on the lathe.  Faced both ends and applied a chamfer to remove the internal burr, then a second face/chamfer to length.  Finally a pass with some Scotch Brite to remove the external mill finish.

The OD of the tube measures 2.002" and the ID 1.502".

I also ordered a piece of 6061 4" round bar on eBay from which to make the beam mounting bracket.  I noticed that this bracket attaches to the top flange of the cylinder via 6 M4 screws, which means that the matching holes in the flange must be clearance and the holes in the bracket tapped.  But the other two hole in the flange (those over the port block) must be tapped in order to secure the matching holes in the cylinder cover.
Vehicles & Models / Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Last post by Firebird on Today at 09:31:38 PM »

Moving onto the crossheads.

Once again gun metal castings are available but at nearly 40.00 its worth making them. I am using cast iron because I have a bit. Cast iron and the steel of the slide bars are a good combination of materials.

Firts job is to machine the block of cast iron to size

Then each side has a 5/16" wide slot machined

Testing with a bit of 5/16" square. Aiming to get a good fit

My usual method of printing out exact size and gluing to the work piece

In the mill and machine away some of the waste. I have enhanced some of the print out with a marker pen



From Kits/Castings / Re: Textile Mill Diorama
« Last post by john mills on Today at 09:21:31 PM »
The bronze bush should be a tight fit in the hole  when the cap is bolted down as is meant to hold the bearing
in place the pin locates for assembly .with automotive bearings the lugs on bearing shells locate on assembly
but the shells will soon spin if the tunnel sizes are too  loose .
From Kits/Castings / Re: The Dickson!
« Last post by crueby on Today at 09:12:27 PM »
Great job on the base, thats a lot of holes to get lined up.   :ThumbsUp:
From Kits/Castings / Bearing Pin
« Last post by J.L. on Today at 09:08:19 PM »
Disregarding my camera's parallax, this diagram is self-explanatory.

I would think anohter advantage to installing the pin would be that bearings tend to run themselves in and become comfortable in a certain position. If the bearings were taken out and put back in for any reason, without the pin, the bearings would probably not return to the same position.

Probably a small point, but worth considering. The bearings should be concentric no matter where they are positioned before tightening the caps, but you never know...

Drawing Credit:
Ernest Winter, Building the Bolton No.7 Horizontal Mill Engine, 1992, pg. 21

From Kits/Castings / Re: The Dickson!
« Last post by maury on Today at 08:52:20 PM »
Guys, Thanks for all the nice comments. I decided to jump in on the main castings for the Dickson.
The base Plate seems like a good place to start.

1) the casting was a bit rough, so I did some initial fettling to get it where I could get a good
setup for the first cut. This is important because everything will be referenced to it.

2)Bearing Mount Holes: After the first cut, the casting was fettled some more to get a good top side
setup.This setup was maintained for the remainder of the machining of the part. The column pads and
main bearing cap pads were machined to finish height. Then the stud holes for the mains were drilled.

3) Base Mount Holes: The base mounting holes were located and drilled. There were small discrepencies
between the Dims and the locations of the pads on the casting.So I centered the holes on the pads and
recorded the dims on the drawing for future use on the foundation casting.

4) Mains: Since the stud Holes intersect the trough for the mains, they were done first. Then the
trough was cut to Dim.

5) Columns: Notice the hankypanky with the clamps. They were moved one at a time to preserve the setup.
Had to do this twice. I did sanity check the setup with the DRO before proceeding each time.The 48 column mounting holes were drilled and tapped. a bit tedious.

6) the machined bed plate.

Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by crueby on Today at 08:43:29 PM »
Looking really good Chris,
I see the elves are starting to get over there camera shyness........what are they up to I wonder :thinking:

Cheers Kerrin
Huh? Oh, couple seem to have wandered into camera range. Unusual, they don't normally get in the shots, muttering something about an open warrant from the North Pole and witness protection...

Your Own Design / Re: Cylinder & Piston Materials
« Last post by bent on Today at 08:26:54 PM »
Delrin breaks down by hydrolysis in hot water, so it's a no-go with steam.  Go with PEEK, polyimide (kapton), polysulfone PSU or polyphenyl sulfone PPSU or polyphenylene oxide (PPO or Noryl) for steam.  Teflon works to, but it's soft.  And all plastics will have expansion coefficients about 20-50 times larger than typical metals.

But for anything up to 180 F, Delrin (acetal) is lovely stuff, it machines so much better than other plastics (PEEK does too, but it's so dang expensive!).
From Kits/Castings / Re: PMR 7 Twin Cylinder Steam Engine
« Last post by bent on Today at 08:19:00 PM »
Yup, those look pretty good.  I recall making two valves for my one-cylinder PMR #3, so you are doing good to make 3 for 2 in my book. ;)
Vehicles & Models / Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Last post by Firebird on Today at 08:11:06 PM »

The brackets are machined from 1/2" square BMS


Not exactly the shape on the plans but they can't be seen and this isn't a show standard engine

The studs I made as one shaft, pushed through with a bit of loctite in the bracket then the centre part hacksawed out. The links are drilled and tapped M3 and the brackets drilled 3mm


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