Taps & Dies

[Doug Mason]

What is the difference between round dies and hexagon dies? Also, should I get adjustable die stock? I'll be using this for general shop work. Thanks for your input.

[Anthony Anderson]

Doug, Hexagon dies are less likely to slip, are easier to work with, since they don't slip in the die stock handle as easily as the round dies. The adjustable stock handles are nice if you are going to be working with a wide range of die sizes. I have a Hanson 76pc metric and standard set, and with rare exception, has taken care of everything that I have needed to do. Here is the set that I have
http://www.amazon.com/Hanson-Tap-Die-Super-Set/dp/B000L7V3SU

When I bought this set (about 15 years ago) Hanson was its own company, and was considered one of the best as far as taps and dies. I have just noticed that they now have Irwin attached to their name, so I am not sure they have maintained the same quality. Good Luck, Bill



What is the difference between round dies and hexagon dies? Also, should I get adjustable die stock? I'll be using this for general shop work. Thanks for your input.

[Doug Mason]

Thanks for the input. I am looking at a basic set from Hanson via W.L. Fuller. I have been buying taps piece-meal but will soon need to get dies for some blank screw stock. It sounds as if I should go with the set having the hexagon dies.

[Mike Heidrick]

Anyone used that GearWrench setup. Borrowing a buddys tap handle by them and it is very very nice. I think I want that tap and die tool set by them!!

[Az Fred]

Hex Dies were/are more automotive oriented and have no thread class adjustment possibility when compared to round "adjustable" dies. A die stock is not required for hex dies. There are also solid round dies and again no adjustment possibility for class of fit. Adjustable dies tend to be more expensive than solid dies and adjustable dies with an adjusting screw are more expensive than without. Most tap and die sets are carbon steel and there is no difference in the steel between the die shapes. Taps are available as taper, regular or common and bottoming. The thread chamfer on the end of the tap controls how close to the bottom of a blind hole you can generate a thread. Unless ordered special dies have a 1-1/2 thread chamfer if I recall correctly. Hex dies as discussed here should not be confused with chasinig dies that are usually "nut size" for national course and fine threads and a definete automotive item.

[Cliff Rohrabacher]

Repeating what has been said excepting the materials.

Split dies tend to be for machine shop use and are almost always made from High Speed Steel just like the taps.

Decent Hex Dies should also be made from High Speed Steel. If they are not, don't buy 'em.

Split dies allow you to fine tune the thread class. In a hobby shop this may - or not be of moment. In a machine shop the machinist is often working to a specific thread class (industrial norm is usually 2-B) and the tradesman will be using a go/no-go guage and possibly even a thread micrometer to the check work to see if it's within tolerances.

My preference in the home shop is for the cruder, less sophisticated Hex dies simply because they are harder to break.

Often I'll be working round stock from some unreputable source such as the BORG. The metal will usually be the cheapest garbage they could find at the lowest price which of course means it's poorly made, will have hot spots, and uneven hardness, and stresses, throughout. It will also not have uniform diameter or roundness even across the length of any given rod.

Adding to the mess is the fact that I'm almost never using a Die on a lathe to hold it steady and true.

These factors tend to mount up to the detriment of any effort to thread the stock. I find that the higher class dies tends to break when the stock is larger than it should be, out of round, or I hit a hard spot, or I'm a tad out of square. The Hex dies on the other hand tend to plow through with a little oil and some elbow grease. They don't make as nice a thread as a good split die on a well machined rod, but it's Strong enough.

In the alternate if you have access to steel that is alloyed with lead (Leadloy) You will find that it is both as strong as regular mild steel and supremely free machining. It drills with almost no heat, saws like balsawood, takes threads like you can't imagine and has no hard spots or inconsistencies in the metal. And it will not work-harden on you.

Leadloy is the finest easiest working steel on the market. You can not harden it though. It won't work-harden on you and you can't harden it in an oven or with a torch. It will not respond to any heat treatment at all.

BMW stub axles are made from LeadLoy. They take a lot of high loading on the splines and plenty of torsional forces. They tend not ever to fail but they are often replaced when the cars need new Constant Velocity joints. So if you want some bar stock that is super free machining stop in at any BMW repair shop and ask them if you can have some old Stub Axles they should hand 'em to you free.

[Az Fred]

I doubt that HSS hex dies are readily available and HSS round dies may well be price prohibitive.

One of the reasons hex dies are hard to break is their tough high carbon material.

Thread strength is maxed out at 75% depth and control of the cylinder to be threaded or the hole to be tapped is imperative for good tool life.

Thread classes are 1, 2 and 3 etc. for NC and NF threads etc and a letter is added A, B, etc for UNC and UNF

My take is that taps and dies are generally used only occasionally in the Creek and thus carbon sets should serve well as a reliable stand by item.