R8 Arbor w/ 3/4 -16 threaded end?

truedblued · Jul 30, 2013

I need as above to fit an older American made boring head to my mill. Anyone know of a source?

jkruger · Jul 30, 2013

Never seen a 3/4-16 thread in a boring head. Only 7/8-20.

truedblued · Jul 30, 2013

Definitely is 16 tpi and minor diameter worked out to .680 near as I could read it.
Same as 3/4 UNF looks like to me.

jkruger · Jul 30, 2013

Wasn't saying that you needed something different, just saying I had never seen one like that. Could be that you might have to make one.

72bwhite · Jul 31, 2013

There are more then one size thread used for the R8 to boring head adapters the two that I have seen both seemed to be fine threads.
Do a web search see if some one list what you need.
Good old ebay might turn one up

L Vanice · Jul 31, 2013

Your most practical solution is to make a 3/4 or 7/8 inch straight shank arbor to fit the boring head and use it in an end mill holder or collet. Larry

oldbikerdude37 · Jul 31, 2013

L Vanice said:
Your most practical solution is to make a 3/4 or 7/8 inch straight shank arbor to fit the boring head and use it in an end mill holder or collet. Larry

That or get any arbor and weld it on.

I weld the arbors on anyway so it can be run in reverse.

duckman · Jul 31, 2013

I've never had a boring head unscrew from the arbor, maybe what I do is not correct but it works for me, clean both pieces, I mean really clean I wash then with acetone, blow dry and clean them again, then here's the fun part, put too much non removable Locktite in the boring head , before doing this mount the arbor in your machine, now screw the head on to the shoulder then remove it, make sure the slide is even/flush with the sides of the head, set machine for about 800 RPM screw the head on about 3 or 4 turns , now wearing a glove and using 2 fingers I start the machine and grab the head with enough force that the head screws on very rapidly and slams into the shoulder, let cure 24 hours I've never had one let go after doing this.

4GSR · Jul 31, 2013

The Chandler Duplex boring head uses a shank with a 3/4-16 NF thread with a 1.250" register for the head to mount to. I have a R-8 with that thread on it but it is not for sale. But I've be glad to draw it up for you if you like. Send me a PM if interested.
Just thought of something here, there is a eBay seller xtrucker that used to have some of this tooling on hand. You may try to contact him and see if he has anything available. Ken

sawz5 · Aug 5, 2013

duckman said:
I've never had a boring head unscrew from the arbor, maybe what I do is not correct but it works for me, clean both pieces, I mean really clean I wash then with acetone, blow dry and clean them again, then here's the fun part, put too much non removable Locktite in the boring head , before doing this mount the arbor in your machine, now screw the head on to the shoulder then remove it, make sure the slide is even/flush with the sides of the head, set machine for about 800 RPM screw the head on about 3 or 4 turns , now wearing a glove and using 2 fingers I start the machine and grab the head with enough force that the head screws on very rapidly and slams into the shoulder, let cure 24 hours I've never had one let go after doing this.

I am very afraid that one day you are going to lose two fingers or break your wrist, or even worse lose an arm.
One of the first things I was taught in high school (45yrs. ago) don't get close to moving machines with loose clothing.

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R8 Arbor w/ 3/4 -16 threaded end?

truedblued

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jkruger

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truedblued

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jkruger

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72bwhite

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L Vanice

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oldbikerdude37

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duckman

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4GSR

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sawz5

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