gkamysz

My Feedback: (19)

.75/3000 = .00025mm per thread. That's .00125mm for 5 threads. 5/100,000ths of an inch. I guarantee threads are not that accurate tap, die, or whatever method used to manufacture in a home shop. If mating parts are made on the same machine there is no worry. If I making a threaded head to fit a Norvel .074 I don't have that option.

pe reivers

Greg, can you elaborate on that calculation?
In your previous post I thought you stated a deviation of 1/3000 " per pitch!  For 5 threads that would be 5/3000 " which is 0.042mm
When mixing imperial with metrics it is important to know which is what, so it may be my bad
Metrics never are noted like 1/3000, which would be 333 nanometer, or 1/3 micron, which indeed is a very acceptable deviation and very interesting to try on my Myford (without Norton gears).
Could you make a scan of the relevant part of the machinist's handbook.

gkamysz

My Feedback: (19)

Error of 1 unit in 3000. This was taken from the manual for the Atlas lathe I used to own.

This is the chart for the Atlas Craftsman. 8 TPI leadscrew 32T on the spindle. If the myford is the same it should work just as well, provided you have and can fit the called for gears. The only bother is that you can't disengaged the halfnuts to get back to the beginning of the thread.

http://peterrimmer.myby.co.uk/images/gearchart.gif


I found the Atlas manual online.

http://www.scribd.com/doc/34415359/M...Atlas-Press-Co

In the menu on the bottom, go to page 81 for the metric threading section.

gkamysz

My Feedback: (19)

Oh, the Machinery's Handbook refers to another section for doing convergent calculations to select gears to match a required ratio. It's just too many pages to scan. You can do better at 1 in 8000 error with an 80:63 combination without having to go to the large 127:100 gear.

Motorboy

Use the two programs NthreadsP and BoxftrhreadP and calculate which change gear will make the treads you want to make in your own lathe.

Download the programs from this link: http://www.lathes.co.uk/latheparts/page14.html [sm=thumbs_up.gif]

pe reivers

Thank you Greg and Jens
My lathe has a 8tpi lead screw and 22T on the spindle.
I have already invested in a reversing switch, so I do not have to disengage the nut. One day I will need this, I'm sure. Like stated above, taps and dies work well. I can handle specials as well, just don't ask me how!
I have been contemplating to drive both the spindle and sled using CNC technique. Can't find the time to do it right now, but it would give the old lady a new leash on life.
I also have a mill with rotating 4th axis thrown in. Nice stuff. It provides the closing of gaps between lathe and mill, when machining and setup time is not important.

gkamysz

My Feedback: (19)

http://www.duncanamps.com/metal/software.php

On this site there is a program specific to the Myford ML7 for selecting gears for threading. I didn't look at it as it serves me no purpose, but this should be useful as it will select gears for TPI and mm pitch.

Motorboy

I has used this program for Myford ML7, in case you has other lathe than Myford ML7 then you can set up the parametre adapted for your lathe with known gearsize and distance between spindle and lead screw.

But the program for Myford ML7 will not works with 127 tooth gear as a set up, then i selected the program NthreadsP from http://www.lathes.co.uk/latheparts/page14.html since the program will support the 127 tooth gear.

yamaha74

Has anyone seen / have pics and specs of making diesel heads ? ...how the screw works, how the contra head fits, shape of chamber, etc. I work in a CNC machine shop, and might as well make my own

yamaha74

Found some history with info / pics of some F2C high performance
high rpm diesels from europe.

<font size="2">

http://www.go-cl.se/f2c_eng2.html</p>

http://www.go-cl.se/trh/f2c-eng_hist.html

Also an article with pics on design, etc of diesels

http://www.modelenginenews.org/vivell/</p></font>

Recycled Flyer

This is courtesy of Keith Renecle of South Africa and is his own design for a MVVS 49 that simply uses a slice of silicon tubing as the contra piston seal - apparently its good for about 12 months of solid flying until a replacement is needed but for the cheap price of the tube and the ease of changing it who cares?

AndyW

My Feedback: (1)

Well, guys, I've owned a Taig lathe for over 25 years and have the milling attachment and both the three and four jaw chucks. I can do math but I don't use it much. I do it all by hand, by TLAR and sometimes by luck. I most times get it right the first time, sometimes, one pass too many and 4 hours of work go out the window. That was in the early years.

You can do a lot with a Taig and a few attachments. Making diesel heads is a cinch. But I also managed a crankcase along with an engine tank/mount as shown. This engine has parts from Norvel, Cox, Wasp and G-Mark.

It would be great to have all the equipment that's been shown. But it's not necessary,,, with a little ingenuity, you can do a lot. For instance. If I need to dress the outer diameter of a piece that has a bore, I chuck up a piece of hardwood to a just snug fit on the ID of my piece. Then I slip that piece on and slobber the exposed end of the wood with water. This swells the wood and firmly holds the piece. Then I dress down the OD of the piece. I can leave it overnight and the wood dries out and the piece slides off easily. OR, a heat gun can hasten the process.

If you just want to give machining a try, the Taig is a good choice. A few hundred dollars will get you going to do up heads for Norvels. The .06 and .07 heads can use the original head clamp. A good friend in Greece did up a bunch of threaded blanks for me so that I can make proper, threaded, diesel heads for the Norvel .15,.25 and .40. Prior to that, I used the original head clamp and an O-Ring loaded disk instead of an O-Ringed piston. There just wasn't enough room. But it worked, the disk didn't jam because the engine vibration sort of rattled it along when adjustments were made. It did jam though when the engine wasn't running.

Initially, just make up some wheel collars. ID,OD and parting off are three basic things you'll learn. Then you need to thread the setscrew hole,,, which you need to drill out first. That's where you get a drill press and a good, drill press vice.

Learn by doing, try and try again. Read some but that can get pretty heavy and complex with equipment you'll probably never own. Machining can be an entire hobby by itself. I went to the Hobby Show in Toronto many years ago. The Machinery Club had a display and you would be blown away. We make scale models of airplanes. They make scale models of old, classic lathes that originally weighed several TONS. Their miniatures were fully working, scale models. That's not most of us, most of us here, have Aircraft as the main focus and machining is to facilitate that activity. One guy in Toronto told me that he started out that way but found a love for machinery that overwhelmed his love of aircraft. He was the builder of one of those fabulous, scale lathes. Could happen to any one of us.

For me, it's the airplanes and engines. But I can't imagine doing without my lathe. Even if I didn't become such a fanatic about small engines and their tinker factor. That lathe will pay for itself in just a few years. I keep my cars ten years and longer. I've made parts for them on my humble Taig and kept them running and running and running. I live in an older home. Lots of plumbing jobs have been made easier because I owned a lathe.

The crankcase on the engine shown was done on the Taig with milling attachment. I used a gem polishing tumbler and glass shards to affect the flat finish.

AndyW

My Feedback: (1)

While doing a search for a link to Taig, http://www.taigtools.com/ I came across this http://lathes.jrbentley.com/ Imagine, a half scale miniature of the Taig. Now THAT's a love of machine work for it's own sake. I can only marvel at the skill and dedication.

His comments on making the miniature Taig. Seems that it was his first time using a mill. Wow.

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A few words about milling and the Taig Micro Mill.....

I have the Model 2018 manual mill with the stock Franklin 1/5 hp motor. There are no less than 145 slots, grooves, dovetails, and profiles in this project that required milling. I couldn't believe how easy this model was to build using the mill. This is the first time I have used this, or any other vertical milling machine and I have never seen anybody else use a mill - either in person or on television.

Invariably, I have come from the shop feeling refreshed and rested after spending time milling. It seems far easier and less intense than lathe work. My levels of eyestrain seem to be significantly reduced over doing other shop or computer work, or even watching television. Perhaps my expectations were too low in the begining, but I certainly am pleasantly surprised!

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And BTW, this master machinist has enhanced his "big" Taig with a lot of bling. I love it but for starters, not needed.

maxtenet

I have a Taig and all the attachments. Not only have I used it to make many diesel conversions, I also Machined a Titan .60 from the kit and also a .12 and .09 engine which I copied from other designs. You don't need a threading attachment to make a simple diesel head so how did this post get so off track? For the compression screw and head use taps and dies for cryin' out loud. Yeah, there is trial and error but this thread would deter any novice from even attempting to make a diesel head.

Max

ajcoholic

My Feedback: (10)

If anyone wants a thorough and detailed (with pictures) lesson on how I make my diesel heads, there is an article of mine on this topic published in the latest issue of Fly RC magazine - Feb 2011, just out this week on the newstands.

I have made a lot of heads this way. And no, thread cutting lathe is not required.

AJC

gkamysz

My Feedback: (19)

As long as the head isn't for a Cox or Norvel, no thread cutting is needed. I'll be sure to look up the article!

Greg

AndyW

My Feedback: (1)

Even it it IS for a Cox, (any size) or a Norvel .074 and down, no thread cutting is needed. With Cox, you use an old plug to make a head clamp. From there, plenty of room to make a diesel head that looks a lot like a Norvel plug but with a bolt sticking out the top.

With the Norvels, .15 and up, the head clamps aren't deep enough to accommodate a proper, contra-piston. Having a good friend make blanks for you sure helps.

AndyW

My Feedback: (1)

This reminds me that I was able to make up a diesel head for the TD .010 using a burned out plug. I did need to make a screw carrier out of brass, to reduce the size of the screw that otherwise, would have been needed.

AndyW

My Feedback: (1)

Can't imagine why, with four tries, the second pic comes out supersized. [:@] Kleenex lint sure stands out [X(]

pe reivers

Resize and use upload.