Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: Trucker on June 30, 2023, 07:37:52 am

Title: What tap and die
Post by: Trucker on June 30, 2023, 07:37:52 am

Hi, all
Looking for some guidance on what to look for size wise and where to purchase the right tools, I'm not after a complete set just individual to carry out a one off.
I want to put a thread on one end of a 3.3mm brass rod and then create a cap that can be threaded with the same thread that can screw on the end and be removed occasionally, yes it's small stuff but I'm sure you guys would know how I should tackle this..


Thanks
Trucker

Title: Re: What tap and die
Post by: Bunkerbarge on June 30, 2023, 08:33:04 am

I would run a 3mm die nut down it and buy a 3mm dome nut, or acorn nut, to go on the end.  Die nuts and acorn nuts all available on Ebay, or give these guys a ring:


https://www.rdgtools.co.uk/acatalog/GENERAL_WORKSHOP_TOOLS_.html

Title: Re: What tap and die
Post by: ballastanksian on June 30, 2023, 05:55:34 pm

If tapping a turned end, you can get three tap sets for each diameter. One is tapered to start and develop the thread, the next finishes it and often a third is available with a flat end to complete blind ended threads like you would be after.

Title: Re: What tap and die
Post by: Bunkerbarge on June 30, 2023, 06:11:37 pm

Usually you tap a hole but you thread a rod or turned external diameter.  Taps can usually be bought in sets of three but dies are usually only a single die for a given thread with a tapered lead on one side, you then turn the die over and there is a bottoming face on the other side.

Title: Re: What tap and die
Post by: Trucker on June 30, 2023, 07:09:44 pm

thanks for the replies fellas, all info taken onboard, but, how do i ensure i get the right size die for the rod i have,


Trucker

Title: Re: What tap and die
Post by: Bunkerbarge on June 30, 2023, 07:32:28 pm

If you look at this table you can see that an M3 thread has an external major diameter of 2.98mm:


http://www.apollointernational.in/iso-metric-thread-chart.php


I would expect an M3 die should go down OK.  If it is too tight reduce the diameter slightly with some fine wet and dry but I don't think it would be a problem.  That's the closest metric thread to your 3.3mm so its either go with that or try to find an imperial thread that would be closer to your 3.3mm.  I would stick with M3 for convenience and ease of obtaining a die or die nut.

Title: Re: What tap and die
Post by: Shipmate60 on July 01, 2023, 08:20:04 pm

1/8 inch diameter is 3.18 mm a bit closer so might be an alternative.


Bob

Title: Re: What tap and die
Post by: johno 52-11 on July 01, 2023, 08:42:08 pm

5 BA has a diameter of 3.2mm

Title: Re: What tap and die
Post by: Bunkerbarge on July 01, 2023, 11:47:23 pm

It might be an idea to see what you can find in the way of acorn nuts first.  Using them will make the job a lot easier.  That might then dictate your preferred thread to go for.

Title: Re: What tap and die
Post by: Trucker on July 08, 2023, 07:32:29 pm

update on my threading issue for the rudders, well, ive moved away from the idea of having to use a tap and die, instead ive drilled two holes straight through the rudder and the brass shaft inside using a 1mm bit then ive inserted a pin which can be removed if required and slide the shaft up into the boat thus then the rudder will be free and i can also get to the props if needed,


Trucker