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View Full Version : Are these threading dies defective?



Ron of Va
02-21-2012, 08:57 AM
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?

http://www.hunt101.com/data/500/8-32_die.jpg

aboard_epsilon
02-21-2012, 09:07 AM
here's a grizzly one

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

all the best.markj

KiddZimaHater
02-21-2012, 09:20 AM
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
02-21-2012, 09:22 AM
Designed as a lead-in to align the die with the material?

Ron of Va
02-21-2012, 09:53 AM
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
02-21-2012, 10:18 AM
Are they trying to save money by making a half-assed die? It sure looks like it to me.

MichaelP
02-21-2012, 10:21 AM
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. :eek:

JCHannum
02-21-2012, 10:40 AM
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
02-21-2012, 10:55 AM
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
02-21-2012, 11:24 AM
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 8-32ís (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
02-21-2012, 11:26 AM
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
02-21-2012, 11:32 AM
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
02-21-2012, 11:43 AM
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
02-21-2012, 12:54 PM
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
02-21-2012, 01:04 PM
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:
http://ecx.images-amazon.com/images/I/51WI7pJY93L._SL500_AA300_.jpg

I count seven teeth in that die also.

-DU-

wierdscience
02-21-2012, 01:39 PM
Dies below #12 will often be relieved on the backside,it's not an issue with performance.
If you try to thread an 8-32 screw into an 8-32 die it should go fairly easy even if it shaves a little swarf off.

If your trying to thread these on and it trys to wipe the threads out,then either the die is defective or what you have is a Lefthand die.Did you check that?

Ron of Va
02-21-2012, 01:58 PM
I frequently screw a bolt into a die to clean up the threads, and I expect a certain amount of drag. These dies are so tight that they appear to turn an 8-32 bolt into a 6-32 bolt. I am sure they are not left handed dies.

I have a lot of small dies, smaller than the 8-32 and none of them have missing threads. They all have threads that go all the way through the die. These new ones are 1 inch dies, and typically those small dies come in 13/16th diameter. That could explain the missing threads, but I am skeptical.

I have at least one die like the Union-Butterfield that is relieved on the back, but the threads go all the way through.

If they are supposed to be like that then fine. It is just a new one on me. The next one I order will be made in the USA.

uncle pete
02-21-2012, 02:56 PM
I managed to buy thru a member on this forum a real good selection of brand new Imperial and metric OSG dies. NONE of them look like your example.

And just for general info, Untill I started using those OSG dies, I hadn't ever experienced just how good a high quality die could cut or the quality of the threads that can be made. I'm totally sold on buying good dies. They are worth far more than they cost. I just need a set of OSG taps to go along with them now.

Pete

MichaelP
02-21-2012, 03:17 PM
I second that. The hardware store stuff is an utter garbage when compared with good quality dies and taps.

Void
02-21-2012, 03:20 PM
Pete,

And those are the 1/4" thick dies or the 3/8" thick dies? It would be impossible for a 1/4" thick die to have more than seven full teeth at 32TPI, thus no relief or undercut.

Ron's die is 1"DIA and 3/8" thick, so about twelve threads (teeth) but his die is relieved of about five of those threads, leaving him about seven. Which is what you have if you have a 1/4" thick die.

I do not think the issue here is whether the die is relieved or not. Seems to be industry practice to not have more than seven or eight teeth in a die. Some may have more, some may have less, but not much more or much less.

The issue is (or should be) the quality of the die. Does it cut well and freely? Are the threads well formed and the correct PD?

-DU-

demerrill
02-21-2012, 03:29 PM
If the suspect dies have the usual tapered lead-in on the back side (WRT the OP's picture) then the c'bore of the side shown would preclude the practice of turning the die end for end to extend a thread up to a shoulder, should that be desired.

David Merrill

uncle pete
02-21-2012, 03:46 PM
My OSG's are in various thicknesses depending on size, And your obviously correct that you only have X number of threads that can physicly fit into each dies depth. Those OSG's are like any other die I've ever used, They have the normal tapered lead in so each die starts to gently cut till it's established to a full depth of cut. Ron's pictures seem show a die that's been counter bored. Going by his pictures, There looks to be very little to no lead in. They appear to start cutting a thread at full depth right from the start. If what I'm seeing is correct? Then I'd think those dies are brand new scrap metal.

Pete

gwilson
02-21-2012, 04:32 PM
The Grizzly die is properly tapered to gradually cut the thread.

THE ENCO DIE IS MADE WRONG. There is no way you are going to start a full thread with no long taper inside the die. The taper on the other side of that die looks way too abrupt to work.

Try one with threading steel,but be prepared to send them back. I have never seen dies made like those.