Are these threading dies defective?

[Ron of Va]

I bought two HSS 8-32 threading dies from Enco. The first one I thought was defective, so I ordered another one. The second die is identical to the first. Half of the threads inside the die are missing.

I contacted Enco and attached the photo to the email. They tell me the dies are like that by design. I have a bunch of dies, and none are like that. Now I feel foolish and uninformed. Anybody else have dies like this?

[aboard_epsilon]

here's a grizzly one

http://cdn0.grizzly.com/pics/jpeg1000/g/g6965.jpg

all the best.markj

[KiddZimaHater]

They look defective to me. All dies have a small lead-in, but only about 2-3 threads.
Your photo looks like half of the teeth have been ripped off.

[Dunc]

Maybe

Designed as a lead-in to align the die with the material?

[Ron of Va]

The other side of the die has a lead-in with 2-3 threads beveled inward, typical of all my other dies.

The threads inside appear to be torn off to me also. The email response I got from Enco was that all the threading dies in the warehouse were like that. I say BS, because I have bought several dies from them, and none are missing threads inside the die. (Unless this is something new and something I was trying to find out)

I guess I should order some new ones from McMaster-Carr since Enco says all the dies at the warehouse are like that.

[Carld]

Are they trying to save money by making a half-assed die? It sure looks like it to me.

[MichaelP]

They tell me the dies are like that by design.

Welcome to the new era. Apparently, now the Chinese not only copy tools, but design them too.

[JCHannum]

What is the diameter and thickness of the dies? Have you actually tried them?

It appears that the die has the proper thread form and starting lead on the start side, but has been counterbored on the backside, where additional thread cutting is not needed. I offer no opinion on the design, but give them a try before you discard them as defective.

The threads on the one on the left appear funky, but it is difficult to tell if it will actually produce acceptable threads from here.

[DFMiller]

Iam with JC.
The smaller diameter and fine pitch dies look like that. Give them a try. I have some ones that look like that. You only need so many teeth.
Dave

[Ron of Va]

The dies are 1 inch in diameter, 3/8 inch thick. I tried at least 10 different 8-32 bolts in the dies and none would screw in from either side.

I screwed in the adjusting screw to open them up and still no luck. I forced a brass bolt into the die, and the die peeled off metal visibly changing the outside diameter of the bolt.

I took delivery of a 10-24 and a 10-32 die in the same order from Enco, and neither of the dies were like the 8-32’s (missing threads). If this is the way the dies are being made, then I will find another source. I want my dies to have threading all the way through.

Unfortunately, McMaster-Carr wants about $30 for the die.

[garagemark]

Could they be something like a thread chaser. I've never seen anything like those, but I can add them to the long list of things I've never seen.

[JCHannum]

Try threading stock of the proper size for an 8-32 machine screw. Commercial screws are not all that good of a gage.

Unfortunately, good dies are not cheap, and the cheapest of the cheap will almost always dissappoint. I don't think the chicoms have their act together yet on cutting tools. If you must enonomize, buy Eastern European taps & dies.

[BillDaCatt]

I know this is going to sound silly but here goes...

Do you have an auto parts store or a traditional hardware store like Ace or True-Value nearby? I buy most of my taps and dies at at my local True-Value. They are good quality, most of them are less than $5 dollars, and all but the biggest ones are less than $10 dollars. Besides, it's always a good idea to buy local whenever you can.

Hope that helps.

[Ron of Va]

I know this is going to sound silly but here goes...

Do you have an auto parts store or a traditional hardware store like Ace or True-Value nearby? I buy most of my taps and dies at at my local True-Value. They are good quality, most of them are less than $5 dollars, and all but the biggest ones are less than $10 dollars. Besides, it's always a good idea to buy local whenever you can.

Hope that helps.

Hardware store taps and dies are usually carbon steel, and I prefer high speed steel dies because they last much longer. I used to buy my taps and dies there, but have switched to mail order simply for the HSS. I recently wore out my 8-32 carbon die and was replacing it with HSS.

A quality 8-32 die that cost $30 would be OK if I made my living with them, but the import HSS dies for $9, usually works for me. Or they used to work for me.

[Void]

By rough count I see seven cutting teeth in the 8-32 die. There are also seven cutting teeth in the grizzly die that aboard_epsilon linked to. Obviously the grizzly die is not the same but it does have about the same number of teeth. How many does a die need in order to cut and form a proper thread? At some point inside a die, as with a tap, the teeth are no longer cutting but are just there for guidance or drag.

I have several dies that are not flat on the face but are undercut to some depth. I think I also have several that look just like the OPs.

Testing a die by screwing it on to a commercial bolt is almost never a valid test. The threads on commercial bolts are rolled instead of cut. Most any commercial bolts of studs I have threaded cutting dies on to have some cutting going on. The real test is whether your part that is threaded by the die will work well in a tapped hole or commercial nut.

You can also check the PD using a thread pitch mic or PeeDee wires.

I would bet that their 8-40, 6-32, and 4-40 dies look similar.

Here is a pic of a Union-Butterfield (US made) die:


I count seven teeth in that die also.

-DU-