Threading 3/16" Aluminium Rod
I have just ordered a bunch of 3?16" rod and will be using some of it to build a turnstile moxon antenna for satellite use. I am following the article written by Cebik. Just "Google" cebik and turnstile moxon satellite, no use in linking to his website since you must now login. I have used taps and dies before and have done quite a bit of it so be relatively comfortable. However, I have never done so with small rods such as the 3/16" I just bought. What size die and threading should I use? I have one of those small sets from crafstman. this link shows what size dies I have.
3/16 rod is the same diameter as a #10 screw. Use the 10-32 die not 10-24. Alluminum and softer material are stronger using fine threads. Also use some light oil while threading or the metal will gaul. 73, AJ8L.
Yes, the more threads per inch the better and I use kerosene equivalent for lubrication.
Originally Posted by AJ8L
Thanks@ I already bought #10 stainles steel hardware for the antenna so the 10-32 die sounds like a plan and it looks like I have to order it online from sears craftsman since I don't have it an neither does the local sears hardware... Im not about to drive an hour to the little hardware shop that probably has one in the store for a $4 tool... Why can local hardware store be everywhere??? darn Home Depot! Thanks!
if you can get a couple rods from a local welding shop, the video shows making threads by placing a steel bolt into molten alloy, so the same would work with a steel/stainless steel nut with the right threads.
Mobiling Feels Good! :D Home has a T2FD :cool:
WD40 is a very good lube for machining aluminium; I use it as do many better machinists. Tap Magic is very good but more expensive. Use any lube freely; you really can't have too much.
It's not entirely correct to say that finer threads are stronger.
The coarser the pitch, the deeper the thread.
If the material is not very machinable (eg 6061, which can be "crumbly") the shallow fine thread may break-up and be weak; the coarser thread may be better.
Experimentation will be required.
With hand-threading, bevel the rod and ensure that the stock & die are square in all planes.
Aluminium is "sticky"; as soon as you feel resistance to turning, back-off about 1/2-turn to break the chip, lubricate freely and go forward a little again and so on .............
3/16 aluminium is easy to twist if you try to advance a stiff cut.
Incidentally, there are several kinds of push-on clips or circlips that are often used in antenna building. Examples;
There are many variants of this fastening method; most can be had in stainless steel.
A cruise around your local bearing shop would be enlightening.
Edit; your post implies that you are not near a town that might have a bearing shop.
My machinist mates in the US seem to use McMaster Carr for small parts, in this case;
Last edited by VK2TIL; 08-08-2009 at 06:04 AM.
YES, very good source. Spoiled in having McMaster-Carr corporate HQ in same town.
My machinist mates in the US seem to use McMaster Carr for small parts,
Will Call window for HQ/Chicago distribution warehouse is less than 2 miles from QTH ... blessing every day.
West Coast warehouse is Santa Fe Springs, CA
East Coast warehouse is Trenton, NJ
Mideast warehouse is in Ohio, Dayton?
Likely have Will Call counter with posted hours.
Last edited by W9GB; 08-08-2009 at 04:14 PM.
Thanks everyone, I got the 10-32" die that I was missing and I've done a ton of threading and tapping before so the aluminium was no biggie, just neededto know the threading. I will have to check out the sources for metal as they seem to be more rare to come by now...
If you are still in the Rochester area at this time, there is the Metal Source off the corner of Culver Rd and University Av. I have purchased materials from them at not too unreasonable cost. To go really cheap but can't always find exactly what you want, try Alpco Recycling east of Fairport on Rt 31F a mile or so east of the Log Cabin restaurant in Macedon. Only 5 minutes from me. They sell by weight and is pretty cheap compared to The Metal Source. Stop by if you are in the area! 73, Pete,