COX .049 Head Thread
02-28-2007, 10:50 AM
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COX .049 Head Thread
Hi Guys,
Could anyone tell me the outside thread size at the base of the COX .049 heads?
I am planning on purchasing some dies and taps from Victornet.com
Thanks, Luciano ///
Could anyone tell me the outside thread size at the base of the COX .049 heads?
I am planning on purchasing some dies and taps from Victornet.com
Thanks, Luciano ///
02-28-2007, 12:00 PM
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RE: COX .049 Head Thread
Luciano,
The thread is 40tpi. You will NOT find a stock tap and die for the size needed. I would dare to say Cox did that for a reason. It would cost around $50 to get a 17/32-40 tap made I have no idea about the die. Given how close the threading is on a head to the bottom fin and being it's only a few threads deep I doubt a die would work anyways and would rather have to be cut on a lathe.
The thread is 40tpi. You will NOT find a stock tap and die for the size needed. I would dare to say Cox did that for a reason. It would cost around $50 to get a 17/32-40 tap made I have no idea about the die. Given how close the threading is on a head to the bottom fin and being it's only a few threads deep I doubt a die would work anyways and would rather have to be cut on a lathe.
02-28-2007, 12:50 PM
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RE: COX .049 Head Thread
Thanks Tim.
I was planning on experimenting with 1/2" aluminum bar stock to see if I could make a simple straight .049 COX head adapter for Nelson
or Turbo glow plugs using hand dies and taps. However as you predicted I could not find 17/32-40 dies. It's not a problem though
since both you and Larry can provide .049/.061 head adapters for Turbo or Nelson glow plugs.
Luciano ///
I was planning on experimenting with 1/2" aluminum bar stock to see if I could make a simple straight .049 COX head adapter for Nelson
or Turbo glow plugs using hand dies and taps. However as you predicted I could not find 17/32-40 dies. It's not a problem though
since both you and Larry can provide .049/.061 head adapters for Turbo or Nelson glow plugs.
Luciano ///
02-28-2007, 02:13 PM
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RE: COX .049 Head Thread
ORIGINAL: Falco250
Could anyone tell me the outside thread size at the base of the COX .049 heads?
Could anyone tell me the outside thread size at the base of the COX .049 heads?
02-28-2007, 03:05 PM
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RE: COX .049 Head Thread
ORIGINAL: DICKEYBIRD
Not an answer to your query but an interesting fact: The head thread is the same as the cylinder base. You can remove the cyl. and screw in a glow plug and tell your buddies that you have a rare short-stroke engine.
Not an answer to your query but an interesting fact: The head thread is the same as the cylinder base. You can remove the cyl. and screw in a glow plug and tell your buddies that you have a rare short-stroke engine.
02-28-2007, 03:56 PM
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RE: COX .049 Head Thread
ORIGINAL: DICKEYBIRD
Not an answer to your query but an interesting fact: The head thread is the same as the cylinder base. You can remove the cyl. and screw in a glow plug and tell your buddies that you have a rare short-stroke engine.
Not an answer to your query but an interesting fact: The head thread is the same as the cylinder base. You can remove the cyl. and screw in a glow plug and tell your buddies that you have a rare short-stroke engine.
Anyone else remember the April issue of American Modeler back in the early 70's and the amazing zero displacement engine?
It was predicated on the fact that if you graph the HP to displacement of many model engines the straight line average showed a small amount of positive HP at the zero displacement crossing. From there it ..... well.... you had to remember that this was the April issue...
02-28-2007, 03:58 PM
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RE: COX .049 Head Thread
Andrew,
YES.. I have had to many people asking about TurboHeads for the Norvel .074! I should have the time to get a couple prototype test heads finished this week in between some other jobs.
LAter,
Tim
YES.. I have had to many people asking about TurboHeads for the Norvel .074! I should have the time to get a couple prototype test heads finished this week in between some other jobs.
LAter,
Tim
02-28-2007, 11:52 PM
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RE: COX .049 Head Thread
ORIGINAL: Andrew
Haw!! Or screw in a second cylinder and claim to have a rare long-stroke.
Haw!! Or screw in a second cylinder and claim to have a rare long-stroke.
Hmmm....I wonder if that might be a novel way to make a twin?
03-07-2007, 12:08 AM
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RE: COX .049 Head Thread
ORIGINAL: Falco250
Thanks Tim.
I was planning on experimenting with 1/2" aluminum bar stock to see if I could make a simple straight .049 COX head adapter for Nelson
or Turbo glow plugs using hand dies and taps. However as you predicted I could not find 17/32-40 dies. It's not a problem though
since both you and Larry can provide .049/.061 head adapters for Turbo or Nelson glow plugs.
Luciano ///
Thanks Tim.
I was planning on experimenting with 1/2" aluminum bar stock to see if I could make a simple straight .049 COX head adapter for Nelson
or Turbo glow plugs using hand dies and taps. However as you predicted I could not find 17/32-40 dies. It's not a problem though
since both you and Larry can provide .049/.061 head adapters for Turbo or Nelson glow plugs.
Luciano ///
Here you can find all you need to know to adapt for using turbo plugs.
http://www.rcuniverse.com/forum/m_45...tm.htm#4533758
03-07-2007, 10:30 AM
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RE: COX .049 Head Thread
Thanks Andy,
I certainly will try your solution once I get hold of a turbo plug and M8x0.75 tap.
However I don't know if I can work as precisely as you did, with my imported 10" drill press;
especially on the narrow Norvel plug inserts. The AP plug inserts seem too narrow for the Turbo plug.
My stock three finger chuck is a JT33 taper.
Luciano ///
I certainly will try your solution once I get hold of a turbo plug and M8x0.75 tap.
However I don't know if I can work as precisely as you did, with my imported 10" drill press;
especially on the narrow Norvel plug inserts. The AP plug inserts seem too narrow for the Turbo plug.
My stock three finger chuck is a JT33 taper.
Luciano ///
03-07-2007, 11:19 AM
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RE: COX .049 Head Thread
Luciano,
If you follow the procedure, I'm certain that you'll come up with a good product. The key is to use the Phillips bit of the right size to cut the taper AND the bore for the threads. Despite the seeming crudeness, it really does work well. All credit goes to Japanman for this tip. All I did was articulate it in the posting. Good luck.
If you follow the procedure, I'm certain that you'll come up with a good product. The key is to use the Phillips bit of the right size to cut the taper AND the bore for the threads. Despite the seeming crudeness, it really does work well. All credit goes to Japanman for this tip. All I did was articulate it in the posting. Good luck.
