Anyone know a machine shop that can drill out a 7/8-14 and tap for 1-1/4-12 ?

[AbitNutz]

I have a Redding T-7 toolhead that I would like drilled out from its 7/8-14 and tapped to the larger 1-14"-12 size. I saw one that was done years ago and there was enough meat to do it.

I know any machine shot could do it but if anyone knows one that already has the drills and taps for it, it would likely be much less expensive. I'd rather not but a very expensive drill and tap for one project....but I will if I have to.

I'm a little confused on where to post this....

[deltaenterprizes]

You could most probably buy a used Rockchucker press for the cost of the machine work.
It would be stronger.
I am assuming you want to use this for 50BMG dies?

Ebay has the taps for about $30+ shipping
The 1-11/64” drill is about $25
I would not do it for less than $65-$75
It has to be a starting tap and not left handed thread.

[Jeff Michel]

Were me, I'd find a soul with a lathe, mount it on a face plate, bore and thread it. Fairly straight forward job. It would take a pretty good man to turn a tap that size without the proper equipment.

[deltaenterprizes]

Were me, I'd find a soul with a lathe, mount it on a face plate, bore and thread it. Fairly straight forward job. It would take a pretty good man to turn a tap that size without the proper equipment.

That is another way to do that, still time consuming setting up face plate, cost would be about the same.

[Nueces]

Those Redding turrets are quite heavy and it would take a pretty good sized lathe to swing one offset to center a die hole. A well equipped job shop would likely use a mill to bore (not drill) the holes, then thread mill the threads, perhaps finishing with a tap. These are not bolt holes. Alignment and concentricity are important here. The threads leave nothing with which to directly pick up the hole centers without some tooling and experience. Technical papers have been published on establishing the location of threaded holes.

If I just had to do this here, I'd set up the turret in my Myford's milling attachment. That would give me power feed to bore the holes and I could thread with a boring head in the headstock. I'd make a location gauge with a close fit in the original threads and a concentric hole. Very slow, but effective.

Either slow/effective or faster in a professional set up would be expensive if farmed out because each hole is it's own job. The factory surely uses computer machinery.

[AbitNutz]

Those Redding turrets are quite heavy and it would take a pretty good sized lathe to swing one offset to center a die hole. A well equipped job shop would likely use a mill to bore (not drill) the holes, then thread mill the threads, perhaps finishing with a tap. These are not bolt holes. Alignment and concentricity are important here. The threads leave nothing with which to directly pick up the hole centers without some tooling and experience. Technical papers have been published on establishing the location of threaded holes.

If I just had to do this here, I'd set up the turret in my Myford's milling attachment. That would give me power feed to bore the holes and I could thread with a boring head in the headstock. I'd make a location gauge with a close fit in the original threads and a concentric hole. Very slow, but effective.

Either slow/effective or faster in a professional set up would be expensive if farmed out because each hole is it's own job. The factory surely uses computer machinery.

So....does that mean you could/would do it?

:)

[Nueces]

So....does that mean you could/would do it?

:)

Heh! From long experience, if I let myself give in to enthusiasm and say yes, we'd be looking at months of "Soon, Buddy, soon!"

In your shoes, I would get on one of the home machinist boards and see if some sort of trade could be worked out. You might get to inspect a nice shop and observe some of the work.

http://bbs.homeshopmachinist.net/forum.php
http://www.chaski.org/homemachinist/index.php
https://www.hobby-machinist.com
https://www.homemodelenginemachinist.com

Another idea would be to create a post asking for brainstorming on how to do this with nothing but basic equipment. That would be interesting and require nothing but gray cells and keyboard time.

[deltaenterprizes]

What is your purpose for doing it?

[Nobade]

I'd find someone with a modern cnc mill who could do that job with a threadmill rather than try to do it in a lathe. Once it's programmed and indicated it would only take a few minutes and all the holes would be pointed in the same direction.

[AbitNutz]

What is your purpose for doing it?

I several dies that are that size that I want to use this press for. They're the old, big Nitro Express dies. Impossible to find and when you do, you have to mortgage your house. I want to use my T-7 press....personal preference.

[AbitNutz]

I understand that eBay has a myriad of taps...can someone point me to the exact ones that I would need? I'm going to get a machinist to do this so I would assume he's going to use a milling machine. If not, I'll be going to one that does.

I have been steered away left hand taps...I'd really like to be pointed to precisely what will do the job.

Thanks for your overly kind indulgence.

[akajun]

Sorry, I replied in your thread in swaging.
That toolhead is likely hardened and will require the use of carbide. Carbide taps are expensive and break easy. A quick swipe with a file will tell you how hard. I seriously doubt that a HSS tap would do more than one hole if that plus requiring a 3 foot long tap wrench to push it. Not only that you need **** near perfect alignment and squareness and a tap unless held rigidly held and aligned wont give you that.
Your options are to set up on a faceplate in a 16" swing lathe and bore and single point each hole requiring 7 set ups to do so, that's the time consuming and expensive part, the boring and threading takes a few minutes.
FInd a shop with a cnc vertical mill with thread milling capability. They will knock it out faster than a manual job shop and cheaper.

[country gent]

A manual vertical mill (Bridgeport style) can do this job. set up the t-7s head flat and true. Use a tread mandrel to indicate hole in ( this will need to be made with a good fit on the threads and a taper matching the threads chamfer). a slightly under sized end mill used first to open hole up close ( 1" then a boring head used to bore to tap drill size. Left hand taps cut a left hand thread. What you want is a right hand tap in standard size. There are +005 +010 and +.015 for holes to be het treated. Also there are -.005, -.010 and -.015 for threads to be lapped or ground for fit. You want a 000 right hand tap. On a tap this big a skip tooth desighn really lowers force to cut the thread. SInce this is a thru hole a starting tap can do it start to finish.

With the proper set up this job can be done in a heavy drill press even. Indicate turret hole in to zero and strap clamp down. this requires some tapping around to get right. drill it to tap drill size chamfer and tap. I recommend boring as it wont walk and the radial forces distortion are much less. But it can be done with a drill. the issue will be going from 7/8 14 to 1 3/32 tap drill size the drill will want to grab and bite a lot. and end mill is better here and will cut cleanly but not in the drill press.

Most shops will set this up and have it done in a short time. Its more set up than work, like a lot of things. the right tools and things go quick.

I would set this up in the mill on 1-2-3 blocks with the head 2" above the table and strap clamps to lock it down. indicate hole in with the above mandrel and open up hole with 1" end mill, then bore to tap drill size and chamfer the top of the hole. Tap with a skip tooth right hand tap thru. remove and chamfer the bottom side of the thread.

[JSnover]

What Country Gent said. It's a simple job and actually fairly easy IF you understand the importance of the locations and how to keep everything true.

[deltaenterprizes]

Those Redding turrets are quite heavy and it would take a pretty good sized lathe to swing one offset to center a die hole. A well equipped job shop would likely use a mill to bore (not drill) the holes, then thread mill the threads, perhaps finishing with a tap. These are not bolt holes. Alignment and concentricity are important here. The threads leave nothing with which to directly pick up the hole centers without some tooling and experience. Technical papers have been published on establishing the location of threaded holes.

If I just had to do this here, I'd set up the turret in my Myford's milling attachment. That would give me power feed to bore the holes and I could thread with a boring head in the headstock. I'd make a location gauge with a close fit in the original threads and a concentric hole. Very slow, but effective.

Either slow/effective or faster in a professional set up would be expensive if farmed out because each hole is it's own job. The factory surely uses computer machinery.

You put a counterweight on the opposite side to balance out the part being off center.

[Nueces]

You put a counterweight on the opposite side to balance out the part being off center.

Yes, of course. I was talking about the swing required. It's less than I thought. I went out and measured mine and found that a 10 inch lathe could handle it. That means my Myford 7" could take it in the 10" gap on a faceplate.

Filed away in case I ever suffer form this particular wild hair.

[Pardini]

Probably a long shot.......ask Redding?