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Author Topic: Threading  (Read 8132 times)

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Threading
« on: January 08, 2016, 05:38:54 PM »
I made head patterns for a 1914 Indian V twin and poured them in cast iron. The front and rear heads have a different exhaust port angle and take a 1 3/8" x 24 adaptor for the exhaust pipe. I used lost foam to cast fixture plates to hold the castings at the correct angle and then used a .375" thread cutter to cut the threads. The test plug was turned to the thread of an original head and sized out at 1.360" so I cut the new threads to 1.365 and it accepted the plug nicely.

This head had some cold shuts from a bobble, but it is nice soft cast iron. I started to bore with a boring head on the manual mill, but left it undersize so the center could be established on the CNC mill.



I transferred the head and fixture to the CNC and used a .3125" cutter to clean the bore using the thread wizard. Then I used the same wizard to thread the bore using three passes since it was a first time for me. Here it is with the test plug.



And here with the test plug in ready for the exhaust guide threads to be cut with a tap.

 
If you think you can't do it, you're right.
Re: Threading
« Reply #1 on: January 08, 2016, 05:53:56 PM »
As mentioned above this was a first with the thread wizard and since I wanted right hand threads I highlighted CW movement, but when I ran the program it went CCW. I changed the direction and cut the threads but do not know if I set up wrong or if there is a bug. It wouldn't seem normal to cut the threads from the bottom out.
I sized the cutter to be able to cut the 5/8" x 24  for the exhaust guide, but I was able to get a tap in that extra fine thread. A 3/4" cutter is probably called for, but would this thread  normally be cut in a single operation?
If you think you can't do it, you're right.
Re: Threading
« Reply #2 on: January 08, 2016, 06:41:09 PM »
Very nice Eugene, always happy to see you post your adventures.
My friend has an Indian collection. Working on 3 - 1916 models right now, getting ready for the cannonball in Sept.
Will you be making these to sell ?
Might be able to send some business you way .....



Continue the fantastic work my friend.
Kind regards,
Russ
Re: Threading
« Reply #3 on: January 08, 2016, 06:55:09 PM »
Thread milling is often done from the bottom up. That way you aren't machining down into a pile of chips.
Re: Threading
« Reply #4 on: January 08, 2016, 11:55:03 PM »
Thanks Russ, these are for the Century Cannonball. I hope to have some to sell and plan on traveling in support of team #39.

Garyhlucas, that makes sense with a blind hole, so the choice is given for climb or conventional milling.
If you think you can't do it, you're right.

Offline royce

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Re: Threading
« Reply #5 on: January 15, 2016, 01:54:34 PM »
Very nice! I'd like to try this one day. Questions, Mach 3 or 4? What software is generating your wizard?
Bridgeport Series 1 Rigid Ram Retrofitted w/PMDX126 BOB, PMDX107, Hitachi WJ200 VFD,ESS, Leadshine DM2282 Drivers running Mach4 comfortably.
Re: Threading
« Reply #6 on: January 15, 2016, 03:42:28 PM »
I am running Mach3 and used the NFS wizards for this job. With some of my other projects I have had good results using the wizards written and made available from the user base.
If you think you can't do it, you're right.
Re: Threading
« Reply #7 on: January 15, 2016, 04:23:53 PM »
The last operation was the spark plug hole and thread so I made up a lost foam pattern, poured it and then used the bolt circle wizard to drill for the studs and then the circular groove program with a ballnose mill to size the bosses. This allows the head to be held at the 21 deg angle for the plug opening.





If you think you can't do it, you're right.
Re: Threading
« Reply #8 on: April 08, 2016, 01:18:19 PM »
I threaded the spark plug hole, but had to chase it with a tap. The SAE standard for an 18 mm spark plug hole is 18.039 mm min. major diameter so a go guage is probably in order for that operation. The spark plug bottoms in the intake tower seat of the pocket, so even a bottoming tap is restricted from cutting full reach threads.




Russ, I think the 1916 Indians were different, but I would like to talk to other Cannonball crews. Thanks.
If you think you can't do it, you're right.
Re: Threading
« Reply #9 on: April 19, 2016, 02:53:54 PM »
I would like to combine the three angular slots into a single program. They were created individually in Newfangled Wizard, but require closing and then reopening for each subsequent slot. Any thoughts?

If you think you can't do it, you're right.