internal 5/8-11 tool and insert?

[Bill Kahn]

I am a beginner...

I have a boring bar and some MMT11IR AG60 inserts that go into it that allow making internal threads.

BUT, I need to make some 5/8-11 internal threads, which are larger than these inserts can do.

What bar and what insert do I look for? The boring bar needs to be able to fit into a .5" hole.

Thanks. (Or, thanks for the pointer to the threads that discuss this topic)

-Bill

 

[benmychree]

I suspect that you would have to make one; I have seen them made from a square tool bit, or the could be made from a round bar and a small tool bit through a cross hole. The real question is why do it at all? Taps are not that expensive.

 

[JimDawson]

I would make threads as deep as your existing tool will allow. Then finish with a 5/8-11 tap, bottoming tap if needed. Starting the threads with a boring bar insures that the threads are straight to the bore.

 

[BGHansen]

There's a seller on eBay who has a 13mm diameter boring bar for an IR16AG60 insert (which can cut a range of 8 - 48 tpi). It's item# 163424104546 . No experience with the seller. Looks like most IR16 boring bars are 16 mm (5/8" or larger). Mine is 3/4" so looks like I'd be using Jim's suggestion above as my 11IR boring bars around 3/8" diameter.

Bruce

 

[BtoVin83]

With holes that small I usually tap the hole but every once in a while you need a special thread like odd ball pitch or left hand. I don't like ordering a left hand tap to use once. This what I do as I have drawer full of taps, find one that has teeth big enough to single point the thread and grind all of the teeth off except except one or two at the end. Now you have a small boring bar with a thread profile at the end. Of course if you break it you have to start over, just don't break it.

 

[Illinoyance]

You can find a number of threading bars at Banggood. If you want a full profile insert you will probably need to go with a domestic vendor for the insert.

 

[epanzella]

I gunsmith as a hobby and often have to bore oddball threads for which no tap exists. I keep some square 01 tool steel on hand for such occasions. Usiing a 60 degree carbide lathe tool I turn the profile of one tooth. Then I mill a bit more than the top half away. Going past half gives the cutter clearance. This gives you two teeth, one in front and one in back. Grind off the one you don't need. Heat red and dunk in motor oil. I don't bother to temper. Sharpen by stoning just the top surface. You can make these as big or as small as you need.

 

[mksj]

There is a range of MICRO100 carbide internal cutters that will handle threads in the 10-32 range with a bore of .36" or 8-24 range .49" bore, just an example below but various sellers. Depending on the model, the maximum depth is up to 1.8-2"

MICRO 100 Solid Carbide 60° Internal Threading Tools

Use Micro 100 Solid Carbide Tool Holder to Fix that Boring Bar in Place. Boring is a cutting operation to enlarge an existing opening in a workpiece using a single-point cutting tool. Boring tools are connected to milling machines, lathes, or other machines using boring heads and holders. Boring...

www.travers.com

MICRO 100 IT-3601800 10 to 32 TPI, .360

Use Micro 100 Solid Carbide Tool Holder to Fix that Boring Bar in Place. Boring is a cutting operation to enlarge an existing opening in a workpiece using a single-point cutting tool. Boring tools are connected to milling machines, lathes, or other machines using boring heads and holders. Boring...

www.travers.com

MICRO 100 IT-4902000 8 to 24 TPI, .490

Use Micro 100 Solid Carbide Tool Holder to Fix that Boring Bar in Place. Boring is a cutting operation to enlarge an existing opening in a workpiece using a single-point cutting tool. Boring tools are connected to milling machines, lathes, or other machines using boring heads and holders. Boring...

www.travers.com

 

[MrWhoopee]

With holes that small I usually tap the hole but every once in a while you need a special thread like odd ball pitch or left hand. I don't like ordering a left hand tap to use once. This what I do as I have drawer full of taps, find one that has teeth big enough to single point the thread and grind all of the teeth off except except one or two at the end. Now you have a small boring bar with a thread profile at the end. Of course if you break it you have to start over, just don't break it.

This is how I've done it, but unless the pitch of the tap is the pitch you are threading you must only leave one tooth. I've broken one or two.

 

[Karl_T]

Everede is the answer. One offer on ebay is fuzzy pic, but I think its a 3/8 diameter. The other offer does not state diameter of bar but shows how the end works.

2 EVEREDE TOOL BORING Lathe Bars 7" and 8" | eBay

2 EVEREDE TOOL BORING Lathe Bars 7" and 8" . Condition is Used. Shipped with Standard Shipping.

www.ebay.com

Everede HG6905 3/8" X 6" CARBIDE INSERT INDEXABLE Boring Bar WCGT-2 HEAVY METAL | eBay

USES WCGT-2 INSERT. OVERALL LENGTH - 6".

www.ebay.com

you can buy both carbide and HSS inserts for these boring bars. grind the profile you need.