Round threading dies VS Hex

[bigb]

I read where you use round thread cutting dies to cut new threads and most hex dies are for thread repair. I needed to add about an inch of thread to these hooks and not having any round dies I used a hex die. The threads came out more square like Acme threads but they work fine, is it going to matter and what's the difference? Would a round die give me the sharper threads?

[12V71]

I read where you use round thread cutting dies to cut new threads and most hex dies are for thread repair. I needed to add about an inch of thread to these hooks and not having any round dies I used a hex die. The threads came out more square like Acme threads but they work fine, is it going to matter and what's the difference? Would a round die give me the sharper threads?

I think your hook had rolled threads, that will displace metal higher than the O.D. of the rod. Cut threads usually require the diameter of the stock to be the same as stated on the Die. If you check that rod with a caliper I'll bet it isn't the full size of the existing threads.
There are Hex dies for restoring threads and there are hex dies for cutting threads... Yours is a cutter.

[bigb]

I think your hook had rolled threads, that will displace metal higher than the O.D. of the rod. Cut threads usually require the diameter of the stock to be the same as stated on the Die. If you check that rod with a caliper I'll bet it isn't the full size of the existing threads.
There are Hex dies for restoring threads and there are hex dies for cutting threads... Yours is a cutter.

Sure enough, the rod is a little under, like 3/64" but the nuts fit tight and don't rock. I just jammed two against each other and they cinch up plenty tight. How can you tell my die is a cutter?

[12V71]

Sure enough, the rod is a little under, like 3/64" but the nuts fit tight and don't rock. I just jammed two against each other and they cinch up plenty tight. How can you tell my die is a cutter?

Rethreading dies have "teeth" that are designed to roll or displace metal back where it is supposed to be without removing any. They actually look dull. Kind of like a nut with straight cuts vs a sharp cutting edge.

[bigb]

Thanks, and to think I had 9 weeks of machine shop in high school and I wasted it.

[CAVEMANN]

The die also says "START FROM THIS SIDE", I've never seen a rethreading die that said anything on it other than size, pitch & make.

[VaughnT]

I've heard a lot of very educated machinists insist that the hex dies are meant for cleaning up damaged threads, but they can never explain why. Sure, there are thread-repair dies that also have a hexagonal outer body, but that doesn't mean a die with a hex body is automatically meant only for cleaning damaged threads.

The only repair "dies" I want are the two-piece or clamshell variety that allow you to wrap around the threaded portion wherever you want. Most threaded pieces are going to be buggered up on the ends where someone banged them around with a hammer, exactly where you need to get with a traditional die but can't because the threads are all buggered up!

If it's a solid die like yours, it's for cutting new threads and can also be for cleaning up threads if you can get to them. The outer shape doesn't matter at all other than making the die far stronger in the wrench unlike the round versions that rely entirely on the grub screws to stop them from spinning.

[CAVEMANN]

I've heard a lot of very educated machinists insist that the hex dies are meant for cleaning up damaged threads, but they can never explain why. Sure, there are thread-repair dies that also have a hexagonal outer body, but that doesn't mean a die with a hex body is automatically meant only for cleaning damaged threads.

The only repair "dies" I want are the two-piece or clamshell variety that allow you to wrap around the threaded portion wherever you want. Most threaded pieces are going to be buggered up on the ends where someone banged them around with a hammer, exactly where you need to get with a traditional die but can't because the threads are all buggered up!

If it's a solid die like yours, it's for cutting new threads and can also be for cleaning up threads if you can get to them. The outer shape doesn't matter at all other than making the die far stronger in the wrench unlike the round versions that rely entirely on the grub screws to stop them from spinning.

There are also many "HIGH END" sets that contain the clamshell type dies designes for cutting new threads, these are probably different than the ones you are talking about, some contain only a single point tool to chase the threads. I have several commercial sets that have hex dies, an old Craftsman set and 3 or four sets off the SNAP-ON truck, including an SAE set from 4-40 t0 1" both NC & NF, & a few NS, & METRIC THRU 13 MM, MOST ARE HEX, I think only 2 small sets have round dies.

[smithdoor]

Typically the hex die is on construction sites for restoring thread.
The round type is used to make new thread.

I have set of round that was from 1960's and just replaced the tap or die that wears out.
Just good set that has good box as in time you will need to place and good box is handy.

Dave

I read where you use round thread cutting dies to cut new threads and most hex dies are for thread repair. I needed to add about an inch of thread to these hooks and not having any round dies I used a hex die. The threads came out more square like Acme threads but they work fine, is it going to matter and what's the difference? Would a round die give me the sharper threads?

[Munkul]

In the UK you pay more for hex dies. They're better for repair work than round dies, because you can use spanners, sockets etc on them and get them into tight spaces.

As for cutting new ones... they all cut the same, depending on quality... hex or round, as long as they're not specifically made for rethreading then its all good.

I'd love a full set of hex dies, but they're too expensive for what I need and use them for.

[bigb]

I was very lucky when I found these at a yard sale for $5 and US made to boot. Granted it was 30 years ago but even then it was a great price.

[VaughnT]

Sure enough, the rod is a little under, like 3/64" but the nuts fit tight and don't rock.

It's pretty neat when you start thinking about all the engineering that went into designing everything so you'd end up with a 3/8-16 thread. They had to do some crazy math to figure out how much pressure to apply to what size stock so the end result would raise up enough of the metal in the threads to hit that target sizing. No idea how they'd do that other than trial and error, but I'm sure the lab guys have some formulas and whatnot -- probably using all those weird buttons on their calculators!

[farmersammm]

https://www.kmart.com/jme-innovation...p-00903764000P

[wb4rt]

Now if someone would recommend a GOOD tap wrench I’d like to replace mine. I have a couple including one that was supposed to be good quality that loosen as you try to tap a hole. It’s aggravating to constantly tighten the handle to the tap.

[farmersammm]

Now if someone would recommend a GOOD tap wrench I’d like to replace mine. I have a couple including one that was supposed to be good quality that loosen as you try to tap a hole. It’s aggravating to constantly tighten the handle to the tap.

I gave up on the new wrenches offered today. Mine all come from Ebay. Old ones that were made right. Mine will still loosen a bit, but the main thing is that they don't break like the new ones made of pot metal (small ones).

[Munkul]

I use an adjustable spanner. I've never, ever felt the need for a proper tap wrench.

[M J D]

I use the lisle tap sockets quite a bit. Starrett or greenfield tap wrenches are really nice but expensive..

[VaughnT]

Now if someone would recommend a GOOD tap wrench I’d like to replace mine. I have a couple including one that was supposed to be good quality that loosen as you try to tap a hole.

I'm a huge fan of the old Greenfield Tap&Die wrenches and handles. You just don't get nicer builds and they made them for a lot of companies back in the day.

The good news is that they're pretty easy to come by on ebay and other places. The key is how the center portion has the look of machined surfaces and no parting lines from being cast in a mold. https://www.ebay.com/itm/Vintage-Lit...AAAOSwxxlgaLar

They will loosen up as you turn, but that's a function of your hand moving the handle and you can't really get away from it. A good wrench will minimize that, but there's always some tightening required as you work the tap back and forth.

[farmersammm]

A wonderful old Beauty I picked some time back on Ebay.



All the good old ones were forged, then machined. They do not break.

You simply can't find tools as good as these anymore. Starrett maybe, but extremely pricey.

[farmersammm]

Leastways.............I believe they were forged.

[CAVEMANN]

I was very lucky when I found these at a yard sale for $5 and US made to boot. Granted it was 30 years ago but even then it was a great price.

I hate that style of tap handle, I very much prefer a "T" handle with a center hole in the, top to facilitate starting the tap straight with a center, some 3 piece tap sets also have a center in the top of the tap. Some of my dies, both hex and round are split with a screw to "open" them a little bit, I also realized thaat most of my SNAP-ON DIES are 12 point & split with the screw to adjust them a little.

[CAVEMANN]

I'm a huge fan of the old Greenfield Tap&Die wrenches and handles. You just don't get nicer builds and they made them for a lot of companies back in the day.

The good news is that they're pretty easy to come by on ebay and other places. The key is how the center portion has the look of machined surfaces and no parting lines from being cast in a mold. https://www.ebay.com/itm/Vintage-Lit...AAAOSwxxlgaLar

They will loosen up as you turn, but that's a function of your hand moving the handle and you can't really get away from it. A good wrench will minimize that, but there's always some tightening required as you work the tap back and forth.

The Greenfield taps & die sets are awesome too, the dies were often 2 piece with a corresponding "guide" to seat the dies in the handle and facilitate starting the die on new material, the two piece dies were also adjustable.

[idacal]

I use the tap sockets also, after breaking a couple of tapping wrenches, would love to have a way to drive the dies with power. I hadnt thought of getting the hex dies then i could use a standard socket to drive them.

[bigb]

I hate that style of tap handle, I very much prefer a "T" handle with a center hole in the, top to facilitate starting the tap straight with a center.

Got a pic? I use this often but no hole on top

[CAVEMANN]

Got a pic? I use this often but no hole on top

Here ya go, the large one & the small one are STARRETT, the medium one is a ratcheting tap handle, couldn't read the brand.