Tapping 2-56 threads

Model Railroader General Discussion (Model Railroader)
1

I’m in the process of collecting various tools for use on the trains for lighting, modifying, detailing, etc.

I’m looking for a set of the tap, drill bit and tap wrench to tap holes for 2-56 screws…as 2-56 screws are so common for coupler and wheel set mounting…

Anyone have any experience tapping holes? Just looking for some recommendations for mfg’s that might have the 3 items in a set? I want to buy something that isn’t junk.

thanks

2

Micro Mark has the tap wrench as well as the tap and drill bits, bit the tap wrench is sold separately from the tap and drill bits. Micro Mark makes high quality taps, drill bits and tap wrench.

Rich

3

Kadee offers a 2-56 tap, #50 tap drill and #43 clearance drill.This is set #246

http://kadee.com/htmbord/page246.htm

I use a General Tools pin vise. A tap handle is not nec most work is styrene, For diecast, drill w/ dremel and tap slowly w/ the pin vise.

I would also suggest that you purchase a 2-56 bottoming tap. This is useful where coupler/ truck screws have limited depth (flats or bulkheads) and a few no. of threads into the frame/ floor of car.

Kadee Delrin 2-56 screws also come in handy. They are easily cut/ trimmed to any size for an exact and proper fit. http://kadee.com/htmbord/page256.htm

4

For many years I have had 00-90, 0-80, 1-72- and 2-56 tap sets which took care of all my model train needs.

The 00-90 were great for attaching Kadee coupler springs fo wipers to trucks for added pickup.

The bottoming taps are also a good idea.

The nylon screws are a good idea if you ever need to isolate a motor that has the brushes electrically connected to each motor frame half.

Get the Aluminum Storage Case with 20 Containers for screws, nuts, washers.

Rich

5

Penn,

You might want to check Micro-Mark. They generally have decent tools. The other option is to go to a production tool store in your town. If you want real quality, look for Starrett for your tap wrench. I generally like the T-handles for hand tapping because they fit in the palm of my hand and gives me better control and “feel” for what I’m tapping into:

For smallish taps like 2-56 and <, look for a smaller T-handle.

For what you’re tapping, Penn, your tap doesn’t have to be a top quality one. What you do want is a tapering tap that has gradually deeper and deeper cutting teeth. Mostly what you’ll be tapping into is plastic and zinc-metal (chassis). A standard tap should do you just fine. For drilling, I would get a good quality coated (e.g. titanium nitride or TiN) drill bit. They cost a little bit more but will last longer for you.

When tapping, always keep the tap perpendicular to the surface you are tapping into. What you don’t want to do is to come in at a angle because you’ll stress the tap and it will be more likely to snap off.

[Side comment: Extracting a broken tap from a hole isn’t the end of the world. It is possible to remove with an tap extraction tool. However, you want to avoid doing that. Rest assured, Penn, that what you’ll be tapping into is plastic and fairly soft metal. With those materials and the depths you’ll be tapping, you’d really have to work at it to snap a tap.]

Use only slight pressure and allow the tap to cut into the

6

I respectfully disagree, Bob. While a pin vise might work for some circumstance, a small T-handle will give you much better control and “feel” for cutting into either styrene or diecast (zinc) metal.

Tom

7

Thanks Bob,

The die cast metal is what I failed to mention in my post and that is exactly what I was interested in. (A bit early for me) Tapping the styrene is no problem. I like the Dremel idea for the die cast. I’m using 2-56 screws from Radio Shack as they are cheap and convenient to get. They are like machine screws. Flat at the tip so would the tap set from Kadee you mention be the right taps? I assume they would as Kadee screws are about the same as the ones I’m using I believe.

Does the drill bit fit directly in the Dremel? Or do I need the special attachment fitted in there?

Sorry for these dumb questions…I could probably figure it out myself but…appreciate your humoring me. I just want to get the right thing the first time if possible. And as ordering this off the Internet and waiting a few days and then discovering I need something else to proceed…well I’m sure you know.

Thx and all the best

Paul

8

With every Dremel set that I’ve seen, they have different sized collets (the part of the Dremel that holds the bits or attachments) to handle different sized bits. Most of the Dremel tools all fit the standard collet.

9

Hmmm, so much for the rest of us - - - LOL [:‘(][:’(][:'(]

Rich et. al

10

I have had good experience with the Walthers #256 drill bits and tap kit. It comes with 2 bits and one tap. I use a pin vise but don’t remember the brand. The vise has more than one collett to hold other size drill bits as needed. Got both from my local hobby shop.

11

Paul,

They could be chassis or tapping screws (NOT the same as machineing screws), which means that they would have much coarser threads and be tapered. The “56” in 2-56 means that that is how many threads there are per inch. What you want is machineing screws for taps.

If the Radio Shack screws aren’t true 2-56 machineing screws, Micro-Mark has them or check you local LHS for the Kadee or Walthers packets. I get 2-56 screws at my local Ace Hardware store because one of the workers is a MRRer. [Y][:D]

Tom

12

When tapping metal use oil on the tap, it really helps. There is special oil for this but just use automotive oil the thicker the better,

13

Thanks for your excellent tutorial…previous post. And the education on the variety of screws. I honestly don’t know what the Radio Shack screws are. Ill verify that. I have an Ace close by so ill check them out and see if they carry the correct version. South Florida is pitiful as far as Hobby Shops that carry RR related items. There is one but I’m not a fan…so the Web is my main supplier.

I’ve been shopping around on the Internet for a good tap wrench…I did look at the stuff Kadee has. Came across Starrett which I believe is top of the line and probably overkill for my applications, amongst others. But from what you and some of the other folks have said it seems a moderately well made tap wrench will suffice. Taps, and drill bits as well…Assumably Kadees products are reasonable. So if I end up going with the Kadee Ill also invest in a supply of their screws…which just seem ridiculously overpriced as compared to other suppliers…

Well, for the moment I have more than enough information to get into trouble. [oops]

thanks again for your time and thorough explanations. Much appreciated.

Paul

14

Got it and thanks

15

Thanks and appreciate all the input.

Best

Paul at Penn Station

16

V8,

Generally speaking, when cutting metals, tap fluid or oil is best for keeping the tap cool and debris from clogging the cutting teeth of the tap. However, when cutting zinc, a good sharp tap will pretty much cut through it like butter. So, oil is superfluous in that particular situation and not really necessary. If the tap is getting dull, it’s just better to replace the tap than chance it - even with oil.

I recently tapped threads in a 3/8" long thru-hole of a Bowser VO-660 chassis. I hardly needed to back off the tap at all before I was all the way through.

Tom

17

I’ve tapped a lot of holes in my life, usually on a paying job. I strongly recommend using a lubricant when tapping zinc alloys. Some, at least, tend to jam up unlubricated taps. Pretty much any old oil will do. This, unfortunately, adds the irritating step of de-greasing afterwards. but dealing with a broken tap is, how you say it?, a total bummer.

Before you try tapping metal, do some holes in plastic for practice–to get a feel for it.

Bought bottoming taps are a nice thing, but you can make your own from a regular tap by using a Dremel grinder. This would be my second choice, but I’ve done it. Also, once or twice, I needed the threads to go even deeper in the hole than the bottoming tap would allow. Again, you can modify a tap with a grinder.

Ed

18

Ed, great idea to modify a standard tap to bottom out. This would thread all the way better than the bottoming tap. Thanks

19

  1. Radio Shack 2/56 screws are machine screws (not “machining”)… I use them anytime I’m out of Walthers, Detail Associates, Micromark or Athearn screws - all cheaper than Kadee screws, (never buy them).

  2. I use Wahl’s Clpper Oil for lubrication when drilling zink, zamack and any soft white metals, many of which like to grab the bit when they get hot. Wahl’s is meant for sharpening and cooling clipper blades and works very well for drilling, tapping and grinding/milling. It’s not “greasy” and will wash off with soap and watter. Many hobby shops carry it or your local barber shop will also carry it, some hardware stores have it too.

20

Thanks, Jay. I had machining on the brain. LOL!

Tom