Which Stuart engine is this

Made the rings today, splitting them no problem, after boring to size I used super glue to stick them on a mandrel, turned them to size, then they split themselves as I took them off, They seem ok, but I won't fit them until I'm ready to do the final assembly. Ian S C

Made new studs for the cylinder heads, the holes in the front head (crankshaft end), seem to have been drilled rather randomly, and don't really line up properly, I proberbly should plug all the holes and start over, but I did'nt. One stud into the front of the steam chest was stripped, and for some reason was near enough to 4 mm, so I tapped it 3/16" UNF, and made a stepped stud to keep the 4BA for the nut. So new studs back and front, little by little. I'v got to work out how to tackle the butterfly in the govenor. As for the cladding on the cylinder, I know sheet metal is normal, but would wood be appropriate for this type of engine? Ian S C

Hi Ian

I agree with Michael and think that blued steel was originally supplied with the kit. My own preferencs is for wood of some sort - I just think it looks nicer!

I have sent you a PM.

Regards

Norman

I made a cardboard template this evening for the cladding.I think I'v worked out how I'll make the butterfly valve for the govenor. I'v got oil cups to do, and drain cocks. I'm thinking of modifying, some little plug cocks that used to be part of an aquarium air system. I noticed that on the bearing area on the side opposite the flywheel there is a large area that has been filled with bronze, whether the casting was damaged like that (blow hole), or damaged by the person who mutilated the rest of it don't know, but it will be ok. Ian S C

The butterfly valve can be made by mounting a sutable dia rod at an angle in the mill vice, use a slitting saw to cut the end at an angle and then lower the saw to take a slice off the rod. Thats how I did the one on my Stuart beam.

Drain cocks can be made with a simple home made tapered reamer

JasonB, the butterfly was a piece of cake, set the rod over to about 20*, and cut off a slice, the spindle is 5/32", and I split that to take the butterfly. After I sort the linkage, a drop of soft solder will hold it in place, I had thought of drilling and tapping -- too much like hard work. The bit that is puzzling me next is the linkage between the flyweights, is there a little bit that fits over the shaft, and sticks out of the slots. At least now I know that the rotating parts require a keyway on the inner part with the pully, would a grub screw through the outer part be enough to take the drive, maybe a brass one. Tomorrow, the Swivel block lever bracket, the Swivel block and the lever, and theValve Lever, I'll leave the connecting rod untill I'v assembled things. Ian S C

Just a little question, what clearance should I allow for the con rod hole in the front cover of the cylinder, I'll be using teflon tape for packing in the gland. I'v got the govenor sorted, but something is a bit out, it needs about 7/16" joggle in the link from the govenor to the govenor body on the steam chest, never mind I'm not changing it. Ian S C

I'm looking at the crankshaft, the keyway has been chewed out by some metal eating insect, well I think the other chap tried using

the lathe as a shaper to plane the keyway, but it did'nt work. I think I should fill the origional keyway, and start again. Is the key all that holds the flywheel to the shaft, or does it have a grub screw?

Ian S C

Several of their other engines use just a grub screw so the No9 may well be the same. If its just going to run for show then a grub screw will be fine but if you intend to drive something then a key would be better.

A tapered gib head key should hold tight on its own or you can add a grun screw to bear on the key which saves marking the crankshaft.

Whats the fit of the flywheel like on the shaft? if its loose it may be better to bore out teh flywheel and fit a bush, the bush can be slit beforehand to form the keyway.

J

Jason, I'v cut the keyway a few thou deeper, and straightened things out a bit with a slot drill, have not measured thw keyway in the flywheel yet, but (in full size) I'm used to making keys to fit unequal sized keyways, so I should be able to fit this one , so tomorrow I'll make a little gib head key. The flywheel fits quite firmly, so thats a good start.

I was reading a bit this afternoon about tapered collets, but I think I'll stay away from that for this engine, it would go well on a hot air engine.

Grub screw damage: on my hot air engines I use brass screws on pullies etc., as these are changed frequently. Two brass screws hold any of the bits on my motors as they don't produce much more than 5 watts at the crankshaft. Ian S C

Hi Ian

"Tubal Cain" shows just the key - no grub screw - in his instructions.

Regards

Norman

Thanks Norman, thats the way I'm going. Ian S C

Hi Ian,

i know you are going with the Keyway, but just for information the new Stuart No.1's have gone from a Keyway to a grub screw. The crankshaft diameter has been reduced where the flywheel fits, this allows the flywheel to butt up against the larger diameter on the crankshaft. The grub screw fitting in at an angle not only stops the flywheel from rotating on the shaft, it holds it snug against the increase in diameter of the crankshaft.

I presume that if there isn't a change in diameter on the crankshaft then the keyway is the better way to go.

Regards,

Sarah

Hi Ian,

To prevent Grub screw damage I drop a slug of copper sheet in the hole before assembly. I know a grub screw should really cut into the shaft for security but on my small engines etc ultimate strength is not a problem.

Best regards

Terry

Agreed Terry, you can also cut a reduced diameter where the grubscrew beds, or drill a dimple in the shaft.

Sarah, This engine is a fair age, it has a forged crankshaft, the flywheel buts against the eccentric that drives the water pump. I made a little gib head key, it fits perfectly, and looks good.    Ian S C

Edited By Ian S C on 17/11/2012 07:30:09

Quite so Ian

Whilst a grub screw might work OK on a model you would need a blooming big screwdriver or allen key to tighten one on a full size engine!

What's more the key looks the part.

Regards

Norman

Your not wrong there Norman, been working with our museum's Ruston Hornsby 6HR oil engine at an open day today, 6' flywheel, keyed to the shaft (how else). The little gib key 1/8th" x 1/8th"x about 5/8th" long looks just right, about a .005" taper was just right. Ian S C

Well I'm getting there, Just discovered I don't know anything about timing the valve gear, Clues perhaps?Please. Ian S C

The valve needs to be ahead of the piston by 90deg plus a little lead of say 7-8 deg.

So looking at the valve chest side of the engine set the crank so the crankpin is furthest from the cylinder (dead centre) then with the grunscrew on the eccentric loosened move it so the max throw is at 90deg and then a further 7or 8.

If you want the flywheel to rotate clockwise as viewed from this side then the max throw will be between the 12 and 1 o'clock position or if you want it to go anticlockwise then it will be between 5 & 6 O'clock

Once you have the timing set you need to ensure the valve opens equally each side, take the valve chest cover off and rotate the engine and watch to see that each port is being opened by the same amount, adjust the valove rod until you get things equal and away you go.

Thanks for that Jason, I was thinking more of 180* + or _, although I have'nt quite got to setting the valve, it may be this afternoon. Ian S C