Any advice on scale theading micro-taps and dies?

[Bob Cleek]

This bit of flotsam came adrif from

 

in a discussion about making working turnbuckles, which require reversed threading and washed up here.

 

I've also encountered the "turnbuckle problem" and "solved" it using the method Kurt describes (non-reversed threads, with one fork set a bit longer, and then just that fork alone tightened as required so both fork shafts appear about equal) , but I was frustrated by not having a reverse thread tap and die, anyway. I once encountered scratch-built quarter-inch scale working turnbuckles on a hundred year old model I restored and they were a joy to deal with. I went searching for micro taps and dies, and reverse threads and got a big case of "sticker shock!"

 

There are the ubiquitous drawplate and tap sets manufactured by the People's Patriotic Jewelers' Tap and Die Manufacturing Collective available for less than $25 on eBay and elsewhere. I tend not to buy such tools, but they were the first I'd found and I figured, "How much more can the decent quality ones be?" Whoo boy! Eight taps and a drawplate in a mid-range priced set was $175 at Otto Frei, the jeweler's tools supply house, and that was their bottom-of-the-line "utility" grade offering.

 

Newman Tools, a tap and die specialty house (http://www.newmantools.com/taps/micro.htm) had even more expensive offerings, but no doubt of acceptable quality. Their prices gave me visions of calling the Suicide Prevention Hotline the first time I broke a tap. Their webpage did have some interesting, if even more unsettling information. They explain that as of 1958, there is a "Unified National Miniature Thread Series" ("UNM") that replaced what was a hodge-podge of threads previously used. I also learned that there are "watchmaker's threads" and "jeweler's threads," although I'm not sure if these are superseded by the UNM standard thread sizes. The watchmaker's threads used to be finer than the jeweler's threads. Newman recommends that: "Because these small taps are fragile, it is recommended that 75% thread be adopted only for soft materials and short threaded holes. As the length of the hole increases, the percentage of thread should be decreased. The depth of the hole to be threaded (*) as a function of the major diameter is provided in three groups and each group has a minimum and maximum for tap drill size. The minimum diameter should be used for soft and ductile materials and the maximum drill diameter for harder and more difficult materials. In many cases the hole diameter does not correspond to a numbered drill, so the closest millimeter drill should be selected."

 

Okay, I get that. Watchmaker's fine threads for brass and stainless and jeweler's coarser threads for copper and softer metals. (I think... assuming there's still a difference under the UNM standards.) But Newman Tools' final disclaimer wasn't particularly reassuring: "The tap drill sizes shown for form taps are only a recommendation as a starting point. Depending on the material being tapped and the depth of the tapped hole, the hole size may have to be slightly increased or decreased to obtain good thread form and good tap life." In other words, "If the tap breaks, the hole's too small and if the hole is too big, you've ruined the workpiece and have to start over." At forty or fifty bucks a tap, no less! (This will have more meaning for anyone who has experienced firsthand how easy it is to break a small tap.) 

 

I have yet to find any source at all for reverse thread micro taps and dies. (Big ones exist, of course.)

 

So... I'm thinking that the only option until I win the lottery is one of those cheapo Asian sets.

 

Does anybody have any experience or recommendations regarding the Asian micro tap and die plate sets? Do they work at all? Are they suitable for modeling purposes, if not for watchmaking? (I'm not expecting to use them on a Rolex anytime soon.) 

　

[vaddoc]

Excellent topic choice Bob. I ve been wanting a set for some time now but as you say the proper ones seem to be made from Stardust and the cheap chinese or indian ones flooding the market are just too cheap. It would be excellent if someone had experience to share.

 

I came across this that seems to be made in Germany and is still cheap but not the generic type. Quality unknown.

https://www.reichelt.com/gb/en/screw-tap-set-m1-m2-5-30-pieces-donau-mgs1025-p214261.html?&trstct=pos_1

[bruce d]

Model engineers who make steam locos and boats face this issue and in the UK these people ...

  https://www.tracytools.com/taps-and-dies

... are among the best suppliers of left hand threads from stock.  I had a quick look at their online shop and found 10BA threads (1.7mm diameter, .35 pitch). I have found them very helpful in the past and they may have access to other small sizes beyond those in their catalogue.

 

HTH

Bruce

[Bob Blarney]

I'm not familiar with micro-sized taps & dies, but it would be a good thing if a manufacturer produced combined drill & tap bits such as these that I find very convenient.

 

https://www.wttool.com/index/page/category/category_id/14558/

 

Since these do not appear to be available, perhaps a fixture that ensures accurate tapping and threading in these tiny sizes would be useful, although this should be doable on a small lathe such as a Sherline.

[druxey]

If tapping on a lathe, surely turning by hand and not under power!

[Bob Blarney]

1 hour ago, druxey said:

If tapping on a lathe, surely turning by hand and not under power!

Thanks for mentioning it. 

[Walt Con]

You might try esslinger.com  a watch repair/parts store.

 

look under tap and die watchmaker set of 14  around $25.00 if I remember

Product Description

This handy tap and die set comes with fourteen different taps and a large screw plate that allow you to thread wire, re-thread stripped threads on screws, and even thread cases. Perfect for working on small pieces that jewelers and watchmakers commonly run into. Now you can repair stripped and damaged threads that were unrepairable before. Sizes include .7, .8, .9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 and 2.0mm for both tap and dies.
 

• 14 taps and dies sized 0.7mm - 2.0mm in 0.1mm increments 48 - 32 TPI
• 3/32" shank works with pin vise, T-handle tap holder or other hand tools
• Works great for jewelry, watches, eyeglasses, electronics, and much more!
• Taps have a screw-like end for cutting threads and a smooth end for collecting the filings
• Screw plate allows you to cut the threads of screws or earring backs to smaller sizes
• Hardened and Tempered Carbon Steel can be used with gold, silver, brass, copper, soft steel and other soft metals
• Plate measures 3.25" X 7/8" Inches (81 X 21 mm)

Edited March 27, 2019 by Walt Con
add info

[Bob Cleek]

7 hours ago, Bob Blarney said:

I'm not familiar with micro-sized taps & dies, but it would be a good thing if a manufacturer produced combined drill & tap bits such as these that I find very convenient.

 

https://www.wttool.com/index/page/category/category_id/14558/

 

Since these do not appear to be available, perhaps a fixture that ensures accurate tapping and threading in these tiny sizes would be useful, although this should be doable on a small lathe such as a Sherline.

I'm not sure what you mean exactly. Drill bits to match taps are certainly convenient when buying blister-packed tap, die, and bit sets in larger sizes, but, as mentioned in the quote in the original post, in "micro" sizes, the diameter of the hole to be tapped is likely going to vary depending upon the material being worked. You can cut deeper threads in softer material, like copper, which means you'd drill a smaller hole for the tap. In harder metals, the threads would have to be cut shallower to prevent the tiny tap from breaking which would mean the hole would have to be larger in brass or ferrous metals. Unfortunately, the manufacturer's instructions there explain that determining the proper depth of thread, and hence, the size of the drill bit for the tap, is a matter of trial and error!

 

Tapping internal threads in small sizes on a lathe is done with a tap turned by hand power. Cutting threads on a lathe, of course, is done under power. Cutting small diameter fine outside threads can be done on a lathe, but I have never heard of cutting small diameter inside threads on a lathe. How does one get a thread-cutting tool on a boring bar inside of even an 1/8" diameter hole? Is that possible?

[Bob Cleek]

1 hour ago, Walt Con said:

You might try esslinger.com  a watch repair/parts store.

 

look under tap and die watchmaker set of 14  around $25.00 if I remember

This is a promising lead. Those look exactly like the Asian-made sets that are all over eBay, but they probably are better quality, if they are like so much of the Asian tool products these days. The one factory makes the same product, but sells them wholesale at different prices depending upon the fit and finish. The US retailers set the specs they demand and check the quality control and pay a higher price for the product they want. This is why the apparently nearly identical  7X12 mini-lathe will be sold by Grizzly and Harbor Freight, but the Grizzly costs more. It seems with a lot of this Asian stuff, when they are stuck with production that doesn't meet the contract specs, they sell it off on eBay and elsewhere for lower prices. If Esslinger is willing to put their label on it, they've probably made sure the product isn't going to make them look bad. I might try a set from them.

[Bob Blarney]

27 minutes ago, Bob Cleek said:

I'm not sure what you mean exactly. Drill bits to match taps are certainly convenient when buying blister-packed tap, die, and bit sets in larger sizes....

In the link, you'll see that the drill bit and the tap are one single piece, not two pieces, i.e. a separate drill bit and a separate tap.  One drills the hole, stops the drill press or lathe, and then advances the bit by hand and continues the tapping when the bit enters the material.

[Bob Cleek]

8 minutes ago, Bob Blarney said:

In the link, you'll see that the drill bit and the tap are one single piece, not two pieces, i.e. a separate drill bit and a separate tap.  One drills the hole, stops the drill press or lathe, and then advances the bit by hand and continues the tapping when the bit enters the material.

Oh yeah! That's pretty nifty. I've never seen those before.

[Sgt Mike]

Those tap and die sets look fantastic.  Thanks for the info, I will definitely add this to my ship yard machine shop. 

[vossiewulf]

If you're looking for a set, Micro-Mark has a decent one that goes from 0-80 to 4-40 for $99.

[wefalck]

I wouldn't buy these old-fashioned plates with many different thread-sizes on them. They are ok for cleaning up threads on used screws, but what do you do, when some of the more frequently used sizes get dull ?

 

These drill-tap combinations are meant for on-site fitting jobs involving short through-holes. For sort of engineering applications they are not really useful.

 

Down to about M1.0 or the Imperial equivalents one distinguishes between hand-taps and machine-taps. Hand-taps have a longer tip with partial threads to provide a better guidance when cutting free-hand. Hand-taps also normally come in sets of two or three with differing depth of the thread, so that one doesn't cut the full depth of the thread in one go - this improves the quality of the thread and reduces the risk of tap-breakage.

 

Machine-taps also come in versions for through-holes and as so-called 'bottom-taps' for blind holes. The latter have a very short tapering of only two threads or so.

 

The best taps (in my opinion) are the ones that have spiral flutes, not straight ones as most taps have. They only seem to be available down to M2.0. The spiral flute seems to leave more 'meat' in the core, hence, they are stronger. They also jam less, as the swarf is moved upwards like for a spiral drill.

 

Industry offers dozens of varieties of taps that are optimised for different types of materials, but these are generally only available from M1.0 or even M3.0 upwards and tend to be very expensive.

 

In both the metric and the Imperial thread systems each tap has a related drill size. However, I tend to make the holes 0.1 mm larger than required in hard or tough materials, if the screw does not need particular holding power. This reduces the likelihood of tap breakage.

 

BTW, jewelers thread sizes are a matter of their own, they don't fit into neither the metric nor the Imperial system, and date back into those dark pre-norm ages.

 

When tapping, I tend to start the tap manually in a machine in order to ensure that it is started concentric to the hole, but finish the tapping by hand, holding the tap in a drill-chuck or pin-vise. It is also a good idea to work the lathe by hand, when tapping or doing external thread-cutting. Most small machines are not strong enough for this and don't have propper stops or clutches to disengage the tap when a certain torque is exceeded. I fitted my lathe spindle with a hand-crank for this purpose.

 

Unless you really buy a well-known brand, there is no guarantee these days that you get quality. As someone noted above, Asian manufacturers flood the market and European/US American dealers buy from them the same stuff that small Asian traders near the factories sell through ebay. So I am getting my needs from these sources now. I don't have that many threads to cut, so that the expense of a branded tool would not be economic. Sure, you may feel the difference, but is it worth paying five or ten times the price for a hobby application ?

Edited March 28, 2019 by wefalck

[druxey]

Great advice, Wefalck!

[vossiewulf]

I've had the Micro-Mark set for about 10 years and have used it fairly often on brass, but not often on steel. However they have worked fine for either material and have cut threads that fit even 0-80 quite smoothly. Unless they've changed their supplier, I would consider it a good purchase.

[Bob Cleek]

22 hours ago, vossiewulf said:

If you're looking for a set, Micro-Mark has a decent one that goes from 0-80 to 4-40 for $99.

 

22 hours ago, vossiewulf said:

If you're looking for a set, Micro-Mark has a decent one that goes from 0-80 to 4-40 for $99.

https://www.reichelt.com/gb/en/screw-tap-set-m1-m2-5-30-pieces-donau-mgs1025-p214261.html?&trstct=pos_1 

which somebody mentioned above, has that very same outfit for 49 pounds, which is about $64 US. I don't know what the shipping brings it to, though. I enjoy perusing the Micro-Mark catalogs and I have occasionally bought things from them when they have good sales, but I have found over the years that a lot of their tools aren't the best quality and are often priced substantially higher than elsewhere. I suppose they'll hate me for writing that, but I know I'm not alone in coming to this conclusion. If you watch closely, you can get some decent stuff for a reasonable price when on sale. (I hope that makes them feel better!  )

 

[oneslim]

Travers Tool has 0-80 left hand taps and dies.  They have the least expensive quality I have found.

 

LH 0-80 tap: https://www.travers.com/4-flute-left-hand-high-speed-steel-taps/p/14-520-080/

 

LH 0-80 die:https://www.travers.com/search.aspx?keyword=Left+hand+die+0-80

 

I have used these to make functioning turnbuckles for the under frame truss rods in 1:20 scale for my Narrow Gauge cars

 

Bob W 

Edited March 29, 2019 by oneslim

[vossiewulf]

7 hours ago, Bob Cleek said:

I enjoy perusing the Micro-Mark catalogs and I have occasionally bought things from them when they have good sales, but I have found over the years that a lot of their tools aren't the best quality and are often priced substantially higher than elsewhere.

Oh, I agree wholeheartedly about Micro-Mark, most of the few tools I had from them were replaced long ago. But in this case, the set has been perfectly reasonable quality although I don't remember what I paid for it- I don't think it was $99. But I've gotten a lot of use from it and everything is still working fine. So if you can get the same thing cheaper, good deal.

[thibaultron]

Something that has not been mentioned, is cutting oil, at least for metals. Any time you are cutting threads in metal use a good cutting oil. For steel, brass, etc. a regulator type will work. For aluminum, use a dedicated AL cutting fluid.

 

When tapping after the tap has been started, turn it a quarter or half turn, then back it out a quarter turn, go back until it bites and repeat. Remove and clean the tap frequently! For tapping with small taps, a block drilled with the clearance sized drill, set on the part,  can be used to keep the tap perpendicular.

 

When tapping on the lathe, the chuck, or the chuck with the chuck key inserted can be used to turn the part by hand. For cutting external threads, the die can be held against the tailstock ram, and pressed to the end of the part. This keeps the die perpendicular until the thread is started. Lock the lathe and turn the die by hand until the thread is started, then back off the tailstock, and either continue turning the die, or unlock the lathe and hold the die while turning the part.

 

Remember, taking time cutting the thread is much better than breaking the tap, and m, having to make a new part!

[Bill Tuttle]

I have suffered through this problem for years.  I acquired an excellent set made by the J. I. Morris Co. in the US many years ago and purchased extra taps to cover breakage.  They only had the four sizes 00-90,0-80,1-72 and 2-56.  Also had a Japanese set that was much smaller but have no idea where I got that set and haven't seen any of those available anywhere.

 

I searched to see if Morris was still carrying them and they don't appear available on their website but a search disclosed the following:

 

https://www.worthpoint.com/worthopedia/morris-miniature-tap-die-set-481307855

 

This is like my set and these are very high quality.  My suggestion would be to watch E-Bay as suggested in the above listing.  All of this other stuff is about the equivalent of small numbered drill sizes and the chinese drill guages.  You just can't count on the sizes of these drill bits unless you get the very high quality and the Starrett drill gauges seem to me to be the only accurate ones.  

[wefalck]

9 minutes ago, biltut said:

You just can't count on the sizes of these drill bits unless you get the very high quality

You mean the diameter is not correct ? I never seem to have had this problem with metric ones, though there are certainly somewhat larger tolerances in cheaper drills. However, I think for modelling purposes we can tolerate these tolerances.

[Bill Tuttle]

Yeah, the diameter varies with the cheaper drill bits and then when I get to checking it, I even find the 61-80 gauges seem to vary, again with the exception of Starrett.  You are right it doesn't really affect our modeling needs but I guess I am just running out of patience as an "old guy" when tolerances even on the less expensive stuff were much closer.  It certainly isn't just limited to tooling, you can't even buy a coat or pair of shoes without some discrepancy in the sizes.  I guess my tolerance levels just need some adjusting .

[wefalck]

Perhaps the Chinese are not so used to Imperial measures and don't have the right gauges. I never systematically checked my drills, but doubt that the metric ones would be off by more than a few 1/100. On the other hand, I tend to buy 'professional' stuff from workshop clearance sales on ebay - needs patience, but when the opportunity arises, I stock up.

[Bob Cleek]

On ‎3‎/‎31‎/‎2019 at 2:29 PM, wefalck said:

On the other hand, I tend to buy 'professional' stuff from workshop clearance sales on ebay - needs patience, but when the opportunity arises, I stock up.

Excellent suggestion! I always keep an eye out for what some of us here in the US call "old 'arn." Tools were simply much better made before about 1950. This is especially so with metalworking tools and woodworking hand tools. The iron in them was higher quality and the tolerances seem to be better. There were "second grade" tools back then, too, but they haven't lasted. If I see an old tool that I expect I'll find useful at a garage sale or an online auction site that is reasonably priced, I grab it.