Tap and die set recommendations

I just bought a couple of sets off eBay for cheap, just taps.  I got two sets of the metric taps, so far they've held up for about 30-40 holes, usually for the 3mm one.  Now that I see how handy they are, I might invest in a slightly more expensive setup.

Look for ones made of high speed steel, HSS. If it isn't specific then avoid them. TIN coated is OK but not required in most cases. Cheaper ones are made of carbon steel and dull easily. I have an old Craftsman set that are hard chromed. These aren't much better than carbon steel. OK for cleaning up a thread but not so good for making new threads.

I get my taps, dies, drill bits from McMaster Carr. There are other good sources as well, but I have no problems with what they offer.

Pete

Tap sets (3) for a one thread.  The set includes a taper, to start the thread.  2nd tap to increase the thread deeper in the hole, and final cut is done with a bottom-ing tap.  There should be available corresponding tap size and drill bit size charts.   Proper size drill bit for the tap. 

Picture: Start, bottom.  Middle, increases thread depth.  Top, is the bottom-ing tap.   A good tap handle is a plus.  Patience is a large part of the project.  Most any lubricant helps.  Removal of a broken tap in the hole becomes a project.  IMO, Mike CT

Thank you all for your suggestions and information, it is greatly appreciated!

Mike CT posted:

Tap sets (3) for a one thread.  The set includes a taper, to start the thread.  2nd tap to increase the thread deeper in the hole, and final cut is done with a bottom-ing tap.  ...

you are 100% correct, but i just want to add that i cannot ever remember needing a full tap set since just about every hole i drill that needs to be tapped is a through hole and even when it isn't, there is typically no need to bottom out the threads.

i have seen some terrible reviews on micro tap and die sets, so shop around carefully but you'll get what you pay for.

When you buy a set of tools like sockets, wrenches and presumably taps & dies, the vast majority sit unused forever.  It's frustrating that one socket or one wrench or tap or whatever costs way more to buy individually than the cost of each in a set if you average out the prices.  So, for the sake of housekeeping I am inclined to buy just the ones I know I will probably use and it may turn out to be roughly the same investment in dollars as buying a complete set.  It mike work for others just getting into the modeling hobby.  just something to think about.

I spent a few bucks each for the sets I have, they're only for very small screws, I think the top size is M3.5.  They've worked flawlessly for the amount of stuff that I do.  I'm like Phil, I just want to be able to screw things to chassis or to a diecast piece.  I just drill deep enough to allow the standard taper tap to do the job.

If I was doing a lot of tapped holes, I'd spend more money on them, but with the amount of specialized tools I already need and mostly have, I can't afford to spend hundreds on on occasional use item like this.

Any through tap can be ground down to an intermediate or bottoming tap. No need to buy three types.

Pete

Good point Pete, never thought of that.

I do thousands of 0-80 and 2-56 threaded holes each year.  A $3 version will not do - look for 2 flute spiral, and expect to pay $8 per tap.  Greenfield strikes me as one brand.  Once I wear them out I grind them off and make bottoming taps, and I do a lot of bottom threading (example: side frame mounting screws).

I don't do nearly as many, the the most used 3mm tap I have is still as good as when I bought it.  I don't do a ton of metal work, most of my stuff is upgrades and fairly minor mechanical modifications.  Custom mounting smoke units is one example.

And I thought I was the only one that ground the ends off of through taps to turn them into bottom taps....it works.

Phil McCaig posted:

And I thought I was the only one that ground the ends off of through taps to turn them into bottom taps....it works.

I think most of us who have worked in machine shops have used this tactic. 

Ray

Still more- if you grind the tip, I would expect that it would anneal the steel, causing is to wear quicker.

Also- Taps break because

(a) they are brittle- and cheap ones are MORE brittle,

(b) because the pilot hole is incorrect - too small, often when we don't have the standard pilot size which is most often a number or letter drill, OR you use a fractional (like 3/64 - "That's close") drill you have as a pilot for a metric tap.

(c) because they are inserted incorrectly into the pilot hole (crooked), and more often

(d) because "chips" load up in the area allowed for this debris.  Once the chips FILL the relieved area, then the tap binds, and can break.

SO- "woodpeckering"-  this technique needs to be used in tapping.  

Turn the tap in 1 turn, then backward 1/3 turn to relieve the chip, with oil to lubricate.  Repeat.

Mike, You can avoid annealing by constantly cooling the cutter. Don't let it get close to red hot. Most grinders have a water reservoir for this purpose. Also I think if someone uses a bottoming tap a lot, they should purchase one. Making one from another style tap is for folks who only rarely need a bottoming tap. In my case maybe 1 out of 100 times if that often.

Pete

I agree with Mike about the proper use of a tap - namely to turn the tap backwards frequently to clear the chips, which helps avoid messing up the tap and also the material into which the threads are being cut.  This is especially true for tapping soft metals like Al or Cu.  I think an investment in cutting oil is worthwhile, not only for using taps and dies but for drilling, etc.  As a DIYer and hobby-ist I have a small bottle that has amounted to a 'lifetime' supply.  Aluminum is a bit trickier - there are some cutting fluids specifically for Al, but years ago, an 'old' machinist (probably younger then than I am now) told me his trick was to use hand cream with lots of lanolin in it.

In terms of grinding off a tap to make a bottom tap - I dunno.  You can only do that once (and you risk messing up the starting threads).  As has been noted, having all three types is useful - one might be able to get away with an intermediate tap plus a bottom tap...

Cutting fluid is at Ace Hardware.  Yellow can for brass, green can for aluminum.  I use the yellow can for zamac.

model-size taps can easily be ground with a Dremel cutoff disc and a magnifier.  I modify any drill that I will use in brass, often sharpen drills down to #65, sharpen larger taps (4-40 and up) when desperate, and get hundreds of holes with home made bottoming taps.

Yes, you get the tap glowing red and it needs to be quenched.  Smaller taps grind so quickly they don't get a chance to get red hot.

Anybody else have a brand suggestion?  Stay away from hobby store taps.

We have large Elliot's Ace hardware stores here in Wisconsin and they handle very good quality drills and taps down to the sizes we use.

Ray

I have a basic Irwin set that I've added to, larger and smaller, and I replaced the set tap handle with a much higher quality Starrett handle.

BUT it also depends on what you're working on. I work on a fair amount of postwar, and Lionel had a quirky habit of using a lot of 4-36 fasteners. Soo I've added a 4-36 tap to my arsenal. 

bob2 posted:

Cutting fluid is at Ace Hardware.  Yellow can for brass, green can for aluminum.  I use the yellow can for zamac.

model-size taps can easily be ground with a Dremel cutoff disc and a magnifier.  I modify any drill that I will use in brass, often sharpen drills down to #65, sharpen larger taps (4-40 and up) when desperate, and get hundreds of holes with home made bottoming taps.

Yes, you get the tap glowing red and it needs to be quenched.  Smaller taps grind so quickly they don't get a chance to get red hot.

Anybody else have a brand suggestion?  Stay away from hobby store taps.

Hanson or Greenfield, that’s what I have....Hanson makes taps for Craftsman, and Snap On......I think Matco too....never had any problems with them......Pat