new gas pipes under construction

[Jim Allen]

Someone asked a question about the typical type of boring used to make machined tuned pipe ID sections. I use a 3/4" X 10" & a 1" X 12" Accusize RH SCLR indexable boring bore for most ID applications. Both use CCMT type inserts & are extremely rigid 45 Rc steel bars.

JA

 

[LohringMiller]

Great work as usual. I picked up some tips for the next tuned pipe project. The best was using thick walled tubing rather than solid bar. Our experiments support using a variable length center section to tune the pipe. We used a pipe with a variable position baffle section to test this. The diffuser worked best in its design position on the header and wasn't particularly sensitive to position changes. The tuned length was set by the baffle cone position. Extreme changes change the pipes volume so that adds another factor. Below is a picture of our pipe. It turned out to be a great pipe for stock 26 cc Zenoahs.

Lohring Miller

 

[Jim Allen]

I'm beginning the machining of a rubber isolated, cradle type tuned pipe mount for this boat. Both the tuned pipe & it's mount will be rubber isolated. The engine's steel exhaust flange & header has also been completed. No type of "O" ring or gasket is necessary for positive sealing.

JA

 

[LohringMiller]

Jim, did your previous pipe mount solidly to the engine? I've broken a lot of pipes that did, even with a Lord mount on the stinger end. I can't say I'm fond of the Quickdraw flex coupling, but it prevents these problems. O rings at the engine end also allow enough flex with a side exhaust. We always ran the flex coupling on our rear exhaust engines.

Lohring Miller

 

[Jim Allen]

Lohring,

None of the pipes used with rubber isolation engine mounts are solidly fastened to the engine. I use the Quickdraw flex coupling or the type of set up shown in the photo, which is not completed yet. Both types are given free movement where they are inserted in either the header piece or the flex coupling. Positive sealing is done with a machined teflon sleeve & the stainless hose clamps shown. The teflon piece clamped on the OD of the header & the pipe is unaffected by heat because there is an air space where it is clamped. The teflon piece becomes flexible from the exhaust heat, but will not melt. I also use this same type system on my tunnel hull.

Jim Allen

 

[LohringMiller]

Sorry, it looked like a solid connection with machined sleeves.

Lohring Miller

 

[Steve Seebold]

I see a really cool looking pipe, what I don't see is a price.

 

[Jim Allen]

The tuned pipes flat section is not parallel to the top of the radio box, therefore a 7* angle is machined in the cradle as a first step. I rough cut the cradle & located it with the round plug on the rotary table. Custom made toe clamps securely holds the cradle for final machining. The adjustable clamp is held in place on both inside ID's of the cradle with 3/32" OD pins which are located in pre-machined holes. These holes are driled after the cradle's 7* angle is machined & they are also drilled at a 7*angle. The 3/32" OD pins are silver soldered to the adjustable clamp pieces a small distance from their ends. Once they are inserted, they can only be removed by being driven out with a 3/32" OD pin. The final rubber isolation pieces will be glued in place with high temperature silicone rubber cement. The cradle will also have lightening holes machined in it's base.

Jim Allen

 

[BobHorowitz]

Jim,

You need a CNC mill.

Bob

 

[Steve Seebold]

I have a CNC mill in my garage that sits idle most of the time. I can help.

 

[henry velasco]

Yes we know

 

[Jack ODonnell]

 

[Steve Seebold]

Hey Henry, rudders are on the machine as of this writing.

 

[Jim Allen]

Jim,

You need a CNC mill.

Bob

Bob,

I have a CNC Mill & a CNC lathe. Neither are used to make model boat parts, however they are used to make money!

JA

 

[BobHorowitz]

Jim, I was just looking at the bracket on the turntable, I just don't seem to use my turntable much anymore. I can always sneak something onto the CNC mill between jobs.

Bob

 

[LohringMiller]

Jim,

You need a CNC mill.

Bob

Obviously he doesn't. You young fellows never worked in shops with only manual machines. It's quite possible to do all the fancy shapes with a combination of castings and manual machines with special fixtures. It just takes more time and gets expensive for small production runs. A small shop doing custom machining would have maybe a dozen machinists, a tool and die shop to make fixtures, and maybe an "engineering" department to work out the design. Today you have one man with a computer and several CNC machines doing the same work.

Lohring Miller

 

[henry velasco]

You think that's why we have one man working the machines and 20 flipping hamburgers

 

[John Beardslee]

You think that's why we have one man working the machines and 20 flipping hamburgers

I think many "Majored in Minimum Wage" and didn't pursue an education in fields that had a "Job" tile with solid prospects of employment. Just my 2 cents after a career in technical education as well as industry.Thanks John

 

[Steve Seebold]

As stated earlier i have a Tormach CNC milling machine in my garage. In the last 6 months I have totally quit taking any outside work so I could concentrate on making parts for RC boats and 1/5 scale gas powered trucks.

I will admit, there are days I get up in the morning and I think, "I don't want to do this today" so I don't even go to the garage/shop.

I'm not doing machining to make a lot of money any more, I'm 72 years old and I need something to do in my retirement instead of sitting on my butt all day watching TV and drinking beer. The drinking beer part might not be so bad, but I quit drinking alcoholic beverages a little over 30 years ago.

I love doing one offs if anyone had a wild idea for something you'd like to have made than nobody makes.

 

[LohringMiller]

PS Steve, I was thinking of you as the "one guy with a computer and several CNC machines" when you had a shop. Another was my friend Mike Bontoft and his NC mill. Henry, you have one of the very few surviving shops that makes low production items with manual machines. We have at least one in my area that specializes in really big but simple parts for the logging industry. It takes a fit into a special niche. Only two of the many manufacturing companies I worked for while going to college survive. One is General Dynamics Electric Boat Division. I bet they build submarines with a lot smaller work force than in my time.

I worry about my grandsons' transition into the working world today. One is flipping burgers, but at least has a job and is living away from home. In my time I got a job in manufacturing in a day with only a high school diploma and a little summer job experience. That company, Lyman Gunsight, was a relic of an earlier age even then. I'm shocked that it's still around. Computers and health care seem to have the only living wage jobs. Even there you usually need more than a high school education.

Lohring Miller