Hello again everyone. Last issue, I talked about using an O-ring as a piston ring. I'd like to start off this issue by sharing with you a response I received from fellow model and scale engine fan Nick Rowland:
'Rusty, I've never tried using an O-ring to replace a normal compression ring, but I've seen it done plenty of times over the years in everything from hit-and-miss models to high-performance scaled V-8 engines. However, have you ever heard of a quad-ring? They're made of the same material as an O-ring, but are made for linear movement (like a piston) rather than radial shaft sealing. I have looked at quad-rings, and I'm sure they would work.'
Thanks for the idea, Nick, and it will be interesting to see if we hear from anyone who has tried using a quad-ring. While I am still on the subject of O-rings, I wanted to share another use for them.
I push my lathe to its limits, often turning flywheels that are close to my lathe's maximum turning ability. When I do this, it can cause what is called 'chatter,' which is the cutting bit bouncing on the piece being tooled. This creates tooling marks on the rim or face of my flywheels. To some people this is a fine look, and I have seen full-size engines with the same kind of marks. But to me, on my own models, it looks bad, and I have adopted an easy fix to stop this problem.
On my lathe and milling machine tooling bits, I have a simple way to help eliminate these tooling marks. Very simply, I keep a handful of small O-rings close to my lathe. I install these on my cutting tools when I think the work I'm doing might cause chatter. If the cutting tool starts to chatter during machining, the rubber O-rings absorb some of the energy. This reduces the movement, or chatter, of the tool. I install maybe a half-dozen of them on the cutter, and will even stretch them over the tip of my tool holder.
Sometimes, the hot, metal chips that fall off while turning on the lathe will melt one or two of the O-rings and they will fall off, and on the milling machine the O-rings have a tendency to creep down into the milling work. When this happens, I simply put on more O-rings or reposition them. And remember: never, ever reach into your machine while it's turning. Always shut the machine down before you install another O-ring or two.
In as much as this column is a place for me to pass along useful tips or ideas that I may have, I would like your ideas, as well. Starting with this issue, I am going to pass along information on one or two models I think are interesting, along with contact information for getting casting kits or plans. This information will be in no particular order, and am I not endorsing any of these suppliers. This is simply a way of letting you know what is available.
Dinky Dears Inc. makes a 3/10-scale John Deere 1-1/2 HP Model E. Phone them at (541) 679-0114.
Richard E. Shelly & Sons makes a 1/3-scale 5 HP Galloway. Phone them at (717) 665-5684.
These tips are for your thoughts only, and your fuel lines may vary. - Rusty Hopper
Have a tip you think other model makers should know? Send it to Rusty Hopper in care of Gas Engine Magazine, 1503 S.W. 42nd St., Topeka, KS 66609-1265, or e-mail: firstname.lastname@example.org