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Tapping Resin

My Railway Recollections Porter conversion came today!
(yay me!)

From the instructions, I am sure that it is well within my modeling capabilities, except one thing. I have never tapped anything. The kit calls for a 2-56 tap, and I have to order one.

What are the bare essentials for tapping resin? I looked on Micro-Marks site and they offer tap sets, and tap wrenches and all sorts of stuff. I know somewhere down the road I will have to tap other stuff, but what do I need right now?
How is this process done?
Any advice is appreciated.


K & S makes a tap set, with a 00×90, 0x80, 1×72 and 2×56 taps and tap handle. This works great on resin and plastic. You will need the tap drills (which drill holes slightly smaller than the size of the screws to be inserted into the newly created threads) and you might possibly want to get some clearance drills, which will drill holes exactly the same size as the screws, which pass through items without threading into the material.

I could have sent all of these items with your order had you asked. Now that I know that you are a new modeler, I will always ask if you have the essential tools necessary to build the items you are ordering.

Al Sandrini
B & F Hobby Shop

One way is to wander in to your local hobby shop and ask for a Kadee No. 246 Tap and Drill set. It has the 2-56 tap, a No. 50 tap drill and a No.43 clearance drill. You’ll need a pin vise capable of holding the drills and the tap. A tap wrench will do the same thing.

Drill the hole-to-be-tapped with the No. 50 drill, change to the tap/pin vise (DON’T do this with a power tool!) and GENTLY “drill” into the hole. The tap is cutting a thread into the resin as you do this. The Recommended Procedure calls for lubricating the tap as you use it and removing (unscrewing) the tap every five or six turns to clean it out.

If you need a “Clearance” hole (something has to fit between the screw head and the tap), use the No. 43 drill. Kadee has provided a fairly complete set of instructions for this.

Good luck — it’s easier than it sounds!!

in Michigan

Pete’s advice is sound, as, of course, is Al’s. I have some of the Kadee sets, and have used them on metal as well. The trick is SLOW AND CAREFUL. They break easily, but with care and proper use will last pretty much forever.

Jim Scott

One more knot on this thread.
Old machinist trick. For tapping sticky materials (brass and zamac, white metal)
Lubricate the tap by running it over a cake of beeswax from the hdwe store or sewing supply.

Really helps keep taps from breaking or wallowing out holes with difficult starting.

O.F. Machinist.

Woodland Scenics sell the appropriate taps market under the Hob Bits range
Some notes of interest
I have another set of notes at home which I can send you later.

Rod Hutchinson

Thanks for the speedy replies guys. I guess I should have made myself a little more clear. I have worked with resin conversions before (in 35th scale armor)So, I know all about what to use as filler, and glue etc… Armor modeling doesn’t usually include the use of screws. (unless you are doing 16th scale R/C) So the whole “models that move” is new to me yes. I have only been into trains now about two years.

Am I to assume that The WS Hob-bits are stand alone deals? Meaning I get the 2-56 tap and I have what I need to cut the threads, or do I chuck it in the pin vise? (seems kinda big for a pin vise)

Again, thanks for all the help guys.


Yep, you chuck it in the pin vise. There should be one mandrel big enough for the 2-56 tap. Both my pin vises (don’t ask why I have two) will accomodate anything from a number 80 bit on up to at least the 2- 56 tap, with four different mandrels to choose from.

You will also need a 00-90 tap and drill set. I suggest strongly you get the Kadee sets. They come with instructions and tables.

Thanks Barry

This was the other site which may be of intrest for those wishing to Drill and Tap

Rod Hutchinson

MicroTrians makes a drill and tap set for their couplers. I would think resin is soft enought you wouldn’t need to tap it. Just screw it in.

Regards, JE

Actually you can use any kind of oil. I use LaBelle.

Regards, JE

You can – but oil spreads across the surface, leaves a residue that’s hard to remove and may attack the material that you’re working on. Beeswax doesn’t attack anything, and you only occasionally get a small clump of beeswax beside the hole that is easily brushed away. Assuming, of course, that you don’t coat the tap with beeswax. A light brush across the surface of the wax is sufficient.


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