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John Lawson
10-11-2005, 10:20 AM
Does anyone know where I can obtain plans for a small propeller lathe?

Evan
10-11-2005, 10:51 AM
Define small.

There used to be a guy in Shellbrooke, Saskatchewan that had a prop copy lathe he built himself. This was for full size props. My boss and I flew out there in a Stinson 108 (flying truck) to pick up a wooden prop. What a cool rig that copy lathe was. About 18 feet long. The original prop was mounted on one side and the laminated wood blank on the other. Both were concentric with each other and turned together. A cam follower traced the original and actuated a plain old skil saw on an arm that roughed out the blank. The follower and skill saw both traveled on a big long piece of all thread in bearing blocks. The finished blank only needed sanding and finishing.

JeffG
10-11-2005, 06:45 PM
Propeller LATHE? Never heard of such a thing! You cast [marine] propellers and then machine them with a really, really, big CNC gantry mill. Lathes are for shafting...

John Lawson
10-11-2005, 06:49 PM
I'm talking about hardwood aircraft propellers up to a maximum of 18" tip to tip.
There is a photo of one in the 1919 edition of Dykes Automobile and Gasolene Engine Encyclopedia, Aircraft section,but absolutely no explanation of how it worked.

Evan
10-11-2005, 07:05 PM
Funny, I just assumed you meant wood airplane propellors for some reason. I guess because that is the only type I have heard of being made on a device called a lathe.

A small copy lathe would be an interesting project.

JeffG
10-11-2005, 09:32 PM
I assumed airplane props too. Just my feeble attempt at a little humor http://bbs.homeshopmachinist.net//biggrin.gif I've seen lots of wooden aircraft propellers. Nice workmanship. Must have been a real art to get them adequately balanced.

winchman
10-11-2005, 11:20 PM
Since a propellor is a screw, seem like the lathe could be used to cut the "threads". You would need to advance the cutter 6" per revolution for an 18x6 prop.

I think you can work it out if you can visualize it as cutting interrupted double-lead threads.

The cutter would have to be some sort of power tool to get a smooth finish. Maybe a Dremel?

Roger

franco
10-12-2005, 07:38 AM
Evan,

I built a small copy lathe four or five years ago for making spokes for old wood-spoked car wheels. These are usually tapered oval and curved, and difficult to make by hand. You are right - it was an interesting project, and took far longer than I anticipated! It's based (very) roughly on one built in the 1850s, and photographed making artillery wheel spokes 1n 1899.

Sorry, no way to post photos at the moment, but I could e-mail a couple if you are interested. At the moment it is making new spokes for a friend's 1912 Swift.

franco

topct
10-12-2005, 08:31 AM
Not a lathe but this looks interesting,
http://www.wood-carver.com/gemini.html
Use an existing prop for a master?


------------------
Gene

Mcgyver
10-12-2005, 08:50 AM
Model Engineer had a series a few years ago on modelling antique rifle stock copy machines - seems like the same general idea.

so how's the original made? I'd guess today its a five axis task, ie like vanes on a turbine but once upon a time it must have been carefull layout work & manual cutting?

Swarf&Sparks
10-12-2005, 08:57 AM
Some good thoughts above. Along the copy machine lines, I think I'd go for something like a laminex router with a small core-box bit. The Dremel just aint up to continuous precise use.

Swarf&Sparks
10-12-2005, 09:07 AM
I just remebered this gadget from an old woodworker mag. Called the dupli-carver, a quick google yielded

http://www.woodcarverssupply.com/store/prodinfo.asp?number=998112&variation=&aitem=2&mitem=9

Essentially a 3d pantograph. A little reverse engineering might prove fruitful http://bbs.homeshopmachinist.net//biggrin.gif
Rgds, Lin

CharlesM
10-12-2005, 10:27 AM
This is a link that shows a J. A. Fay & Egan Propeller Shaper. Scroll up to page 232.

http://www.owwm.com/files/PDF/FayEgan/1924-12-Misc.pdf

[This message has been edited by CharlesM (edited 10-12-2005).]

John Lawson
10-12-2005, 01:34 PM
Thank you, gentlemen.
Worthy of note: The propeller lathe and more modern dupli-carver both evolved from machines built on lathe beds.
Eli Whitney and Sam Colt both made rifle stocks on in-plant made machines based on lathe beds. Dyke's showed a "propeller lathe" that looked like a commercial machine, based on wht resembled a Star lathe bed.
Propeller lathe, milling machine, shaper, surface grinder...all seem to have evolved from lathe attachments. The lathe is truly the most important tool ever devised by man.

Radmachine
10-12-2005, 03:13 PM
Here's yet another copy carver. This one looks like it would be inexpensive to make.
http://www.copycarver.com/history.htm
Hope this helps.

Paul Alciatore
10-12-2005, 05:42 PM
<font face="Verdana, Arial" size="2">Originally posted by Mcgyver:
Model Engineer had a series a few years ago on modelling antique rifle stock copy machines - seems like the same general idea.

so how's the original made? I'd guess today its a five axis task, ie like vanes on a turbine but once upon a time it must have been carefull layout work & manual cutting?</font>

The originals were probably made with only one blade - see Gene's link. The desired airfoil shape for a number of locations along the blade were probably hand drawn and templates were made to match the drawings. Then the wood carving would commence. As the shape of the single blade neared completion, ever more frequent checks were carefully made with the templates. Finish work was likely sanding with appropriately shaped sanding pads. Since it was only a pattern piece and not flight hardware, any mistakes could be corrected with filler.

Then the real prop was made on a duplicator, one blade at a time. With careful alignment, balancing would be minimal.

That was them and CNC is now. I suspect that even today, each prop must be hand balanced as wood density will vary.

Paul A.

franco
10-13-2005, 01:53 AM
Swarf&Sparks,

As you suggested, I have been using a Laminex router and 1/2" core box bit on the spoke lathe for cutting the spoke shanks, then switch to a normal parallel sided flat bottomed bit to cut the spoke tenons. Works well.

franco

[This message has been edited by franco (edited 10-13-2005).]

Swarf&Sparks
10-13-2005, 08:49 AM
This topic goes a long way back http://bbs.homeshopmachinist.net//smile.gif Well before powered flight. Check the Blanchard lathe at

http://www.nps.gov/spar/history.html

or Brunel's block making machines for the RN

http://www.answers.com/topic/portsmouth-block-mills

DR
10-14-2005, 09:17 AM
"Does anyone know where I can obtain plans for a small propeller lathe? "

I've never seen plans for one.

I'm fairly familiar with an automated copying lathe though. This type of machine that could easily make rifle stocks, etc. Suited for virtually any asymmetric shape that's long with resect to it's major diameter. They copy from a pattern, so you need an original to work off of. If the machine uses a mechanical contact follower on the pattern the pattern needs to be fairly rigid. Sometimes the patterns are made of aluminum to stand up to the contact follower pressure. If the contact follower is hydraulic, then follower pressure is not such an issue.

Here's a link to a modern copy lathe.

http://mail.bacci.com/cgi-bin/bacci/pagina.pl?Tipo=macchina&IdM=16&IdF=8&Lin=eng

If that link doesn't work for you Google on "copying lathes" to find it.

Samuel
10-23-2005, 12:49 AM
Saw this and thought of this thread

http://cgi.ebay.com/CINCINNATI-MILACRON-6-SPINDLE-AIRFOIL-BLADE-MILL_W0QQitemZ7535760557QQcategoryZ12584QQcmdZView Item

regards

Samuel