J
JorgensenSteam
Guest
Galloway.
Help Support Home Model Engine Machinist Forum:
zeeprogrammer
Well-Known Member
- Joined
- Mar 14, 2009
- Messages
- 3,362
- Reaction score
- 13
Very cool Pat.
I've enjoyed watching Brian and Tel's builds. I'm sure I'll enjoy this one too.
I haven't been bitten by the IC bug yet. I hope not to until I get an engine running on steam.
I've enjoyed watching Brian and Tel's builds. I'm sure I'll enjoy this one too.
I haven't been bitten by the IC bug yet. I hope not to until I get an engine running on steam.
Looking forward to seeing this one unfold, as you already know I'm happy to help with what I can.
I would go with a CI cylinder liner, it allows you to do all your welded fabrication and then bore a nice straight hole through the lot to take the liner, trying to weld it all around a tube without distortion may be a bit more difficult.
I think you will need at least a basic carb, how else will you be able to mix air/propane as its drawn into the engine.
I'd also be tempted to go with a 7 5/8" flywheel which is near as dam 1/4 scale.
Good luck, Jason
PS start practicing those yellow pinstripes now
I would go with a CI cylinder liner, it allows you to do all your welded fabrication and then bore a nice straight hole through the lot to take the liner, trying to weld it all around a tube without distortion may be a bit more difficult.
I think you will need at least a basic carb, how else will you be able to mix air/propane as its drawn into the engine.
I'd also be tempted to go with a 7 5/8" flywheel which is near as dam 1/4 scale.
Good luck, Jason
PS start practicing those yellow pinstripes now
zeeprogrammer
Well-Known Member
- Joined
- Mar 14, 2009
- Messages
- 3,362
- Reaction score
- 13
Why do you think the reamer moved slightly back and forth?
Or did it just move off in one direction?
You mentioned you drill in step sizes. What size steps did you take?
I'm looking forward to more.
BTW: As measured on my left-footed 'ijk' screen...it's 7.67" ;D
Or did it just move off in one direction?
You mentioned you drill in step sizes. What size steps did you take?
I'm looking forward to more.
BTW: As measured on my left-footed 'ijk' screen...it's 7.67" ;D
mklotz
Well-Known Member
Drills are bulk removal tools. They make holes that are neither round, straight or on size. The accepted procedure is to drill (undersize) to remove stock, bore to make straight and cylindrical, and then ream to bring to size.
The only time I step drill is when the lathe doesn't have the power to handle full size or I'm concerned about too much torque tearing the part from its moorings. For anything less than 1/2" I drill final size, then bore and ream.
Easy when you have two of them, Zee.
The only time I step drill is when the lathe doesn't have the power to handle full size or I'm concerned about too much torque tearing the part from its moorings. For anything less than 1/2" I drill final size, then bore and ream.
Easy when you have two of them, Zee.
What do you mean by "power ream"? Not turning it by hand? What sort of reamer?
It's rare to hand-turn a machine reamer, but also fairly rare to machine turn a hand-reamer.
Reamers will follow a crooked hole. There's a good thread from the early days of this forum on making non-wobbly flywheels. Definitely worth seeking out for those that haven't seen it.
It's rare to hand-turn a machine reamer, but also fairly rare to machine turn a hand-reamer.
Reamers will follow a crooked hole. There's a good thread from the early days of this forum on making non-wobbly flywheels. Definitely worth seeking out for those that haven't seen it.
zeeprogrammer
Well-Known Member
- Joined
- Mar 14, 2009
- Messages
- 3,362
- Reaction score
- 13
Pat J said:
Yes! In keeping with the recent references to Greek on the forum...you will receive (in modern Greek)...
τίποτα
as well as the admiration of many.
G Day Pat,
I have a full size Galloway that looks the same as the one in your first picture, it still needs to be restored.
I would be happy to measure or take happy snaps of bits and pieces for you if you get stuck or would just like to see how things go on the full size engine.
Lance.
I have a full size Galloway that looks the same as the one in your first picture, it still needs to be restored.
I would be happy to measure or take happy snaps of bits and pieces for you if you get stuck or would just like to see how things go on the full size engine.
Lance.
Pat don't go too far with that flywheel, the spokes on my 1/6 scale are parallel and the web is no wider than the spoke so can be done from the thin turned centre section, As I said before if you need any dims of teh actual castings just ask. Infact as the spokes are circular and parallel you could just turn a steel ring for the rim and drill six holes for spokes and weld into a hub. Hit & Miss don't have polished flywheels so the joints will not show.
Will Also get you some pics of completed models.
As teh others have said your reamer will follow an out of true drilled hole so either bore and then ream or just bore, often bright steel rod is a few thou undersize anyway so by boring it to fit the stock you plan to use on the crank you will get a good fit.
Jason
EDIT Pat have a look at the detailed pics of the 1/6 and 1/3 engines on Linley's site thay show quite well whats going on.
Will Also get you some pics of completed models.
As teh others have said your reamer will follow an out of true drilled hole so either bore and then ream or just bore, often bright steel rod is a few thou undersize anyway so by boring it to fit the stock you plan to use on the crank you will get a good fit.
Jason
EDIT Pat have a look at the detailed pics of the 1/6 and 1/3 engines on Linley's site thay show quite well whats going on.
The one on the Right is just about spot on for my castings.
J
Edit, having exchanged a few e-mails with Pat and studies some full size engine photos It would seem that they should have spokes that are tapered when viewed from the side. The Casting kits come with straight spokes.
J
Edit, having exchanged a few e-mails with Pat and studies some full size engine photos It would seem that they should have spokes that are tapered when viewed from the side. The Casting kits come with straight spokes.
Looking good Pat, will you be threading the area below the wrist pin holes to tahe screws to retain teh pin or just have it floating with softer metal ends. I also see that the full size piston has a slightly reduced dia below the rings.
Do you forsee any issues with the increased friction from the 3 wide rings over the two narrow rings as per the casting kits? could be almost 3 times the surface area.
Full size 5hp piston for anyone who is interested, you can easily see the wide rings.
http://home-and-garden.webshots.com/photo/1103629444039077051Eabpou
Jason
Do you forsee any issues with the increased friction from the 3 wide rings over the two narrow rings as per the casting kits? could be almost 3 times the surface area.
Full size 5hp piston for anyone who is interested, you can easily see the wide rings.
http://home-and-garden.webshots.com/photo/1103629444039077051Eabpou
Jason
Is there? The mass of the flywheel will reduce by the cube as you scale it down but the surface area only reduces by the square. Working this out the mass will reduce to 1.6% of the original but teh area will reduce to 6% of the original so the flywheels have 4 times the amount of friction to overcome, this could well reduce the number of revolutions that the engine will miss for as it won't be able to freewheel as easily.
This is just based on basic area & volume I have not actually worked it out taking the radii into account
Just something to ponder over xmas dinner :-\
Pat,
The tap on the pulley side is a decompression device. As you can see the hole goes into the cylinder itself.
The way it works is that as the compression is considerable, you open the tap and as the piston starts its forward movement a little of the compression leaks out the tap, until the piston covers the hole, you also retard the timing at the ignitor before you start cranking ( so it does not break your wrist )
As the engine fires into life you flick the lever on the ignitor to advance the timing and close the tap so you are on full compression and you are ready to work.
Hope this helps
Lance.
The tap on the pulley side is a decompression device. As you can see the hole goes into the cylinder itself.
The way it works is that as the compression is considerable, you open the tap and as the piston starts its forward movement a little of the compression leaks out the tap, until the piston covers the hole, you also retard the timing at the ignitor before you start cranking ( so it does not break your wrist )
As the engine fires into life you flick the lever on the ignitor to advance the timing and close the tap so you are on full compression and you are ready to work.
Hope this helps
Lance.
Thanks for the photos Lance and Pat for posting them, we have no excuse for getting anything wrong now
Jason
Jason
Pat J said:
Best open that valve then
All this talk of Galloways has got me wanting to start mine but I must resist, I'll let you and George work out all the bugs then mine should be a simple build ;D
Jason
- Joined
- Jan 3, 2008
- Messages
- 2,085
- Reaction score
- 17
The piston looks great Pat. What is the purpose of the small grooves between the ring grooves and there at the wrist pin? I am assuming they are oil grooves but wasn't sure...just curious.
Bill
Bill
