Lubricating at Scale
Hello again, everyone. The show season is in full swing, and so far it's been another great year. I have discovered many new and great models - and the people who go along with them - along with more ideas: I'm now looking for plans to build a model out of an old doorbell. These are electrically excited, and run very quiet and smooth. If anyone has plans, please feel free to mail them to me at Gas Engine Magazine or e-mail me at email@example.com
A fellow hobbyist and I spent the better part of an hour the other day discussing different types of lubricants, and we decided graphite is still some good stuff. Graphite powder has been around forever, and is one of the slickest compounds you can get. Yes, you can find lubricants with higher and lower temperature ratings or with better surface adhesion, but if you check their content, you'll find that almost all of them contain graphite. I haven't had any around the shop lately, so my friend offered me 4 ounces of graphite powder to use on my models. It's been refreshing to get my hands on some again.
I like mixing a little graphite with oil, and it will hold for a fair amount of time. Better yet, I have also mixed powdered graphite with a little grease. This mix uses very little graphite, and although it's black and dirty, it works great.
A few years ago, I built one of my first flame eaters and was informed by Jerry Howell of Colorado Springs, Colo., to try making a graphite piston for one. Well, after a quick search I found graphite rod available in 1-inch diameter, 12-inches long, and I've used about half of it now for pistons.
With this type of piston the graphite rolls over itself and the piston is almost friction free. I have bored into the end of the graphite and drilled across it for the wrist pin, and it has held fine, without cracking or any type of breakage.
I have yet to put graphite pistons to the test in a gas model, as I'm worried the fuel will dissolve and break down the piston while running and cause major damage that can't be repaired.
Along this same line, I purchased one of those "cold heat" soldering irons you see advertised on television, and I have found the tips on it are graphite. This iron works very well on small-gauge wire, say 18 gauge or smaller, and with fine wire solder. The iron runs on four AA batteries and costs $20. It can save you a lot of time when you have small wiring needs, and I recommend one for your home shop. I don't believe any of our advertisers handle them, but you can find them at Auto Zone and Radio Shack, or online at www.coldheat.com
I'd also like to pass along a tip that Roland Morrison of Morrison & Marvin shared with me at the NAMES show concerning the use of a parting tool to work the inside of a small crank.
Roland says to take a cutoff tool and grind a "V" into the middle of it, maybe 1/32- to 1/16-inch deep. Mount the cutoff tool as square as possible into your lathe fixture and mount a fine stone into the jaws (one from your 1/4-inch die grinder will work fine). Keep the tool above the center of the stone, then slowly and gently kiss off some from your cutoff tool on the underside until you have squared the tool with the stone. Next, remove the stone and mount your crankshaft back into the lathe, and you are set to get a good square corner on your crankshaft.
My process in the past has been to take the connecting rod and a small, round stone larger than my hole, and break the edges off the bored hole where my connecting rod connects with the crankshaft. The reason I have done this in the past is because I was afraid I did not have nice, square corners on my crankshaft, so I wanted to keep a nice grease barrier between the crank and connecting rod.
Finally, don't forget that the annual Portland, Ind., engine show is just around the corner. Be sure to mark Aug. 24-28, on your calendar, and if everything goes right again this year I plan to see you all there. Is this hobby great, or what?
This month's tip for model and scale parts sources:
• Little Machine Shop handles lathe and milling machine tooling. Contact them at: 396 W. Washington Blvd., #500, Pasadena, CA 91103; (800) 981-9663; www.littlemachineshop.com
• CDCO Machinery Corp. handles lots of precision tools for the hobbyist. Contact them at: 800 W. Central Road, Mt. Prospect, IL 60056; (800) 417-2305.
These tips are for your thoughts only, and your fuel lines may vary.
Have a tip other model makers should know? Send it to Rusty Hopper at Gas Engine Magazine; firstname.lastname@example.org