Has anyone ever threaded a brass shaft for a prop. I am worndering if it is hard to get the threads close to perfect. Are there any tricks, Thanks,Randy.

I have threaded aluminum rod. Brass is harder so it should not be any problem.

Practice. Then more practice. Lots of lube for the die. Then more practice.

Try harder, and use stainless steel precision shafting from a source like mcmaster.com or smallparts.com.

I imagine for our boats, a soft brass shaft running in well lubricated bearings should be ok... but it's not the best practice.


Pat M

Oh, and grab that brass shaft in soft jaws in your vise, don't want to ding it up.

what tap and die set are you planing to use ? one with the two halfs of the die or the round ones ? i find the 2 half ones maka much cleaner thred

I was planing to use a round one.
I ran into a new problem today when I asked the hobby store owner if the 10 32 die was for a 3/16th inch shaft and he said no, but it was close, I can't buy one thats close, so now I am not sure whear to look for a 10 32 thread for a 3/16" shaft.

#10-32 will run down just fine on 3/16" shafting.
#10 thread diameter is 0.190", 3/16" is 0.1875", just slightly smaller... and the threaded prop doesn't pilot on the thread OD, but on the flanks of the thread... no problem.
Put a 45° chamfer on the rod end first, which will ease the die into the cut.

Pat M

1. cutting a #10 thread on 3/16" steel rod
2. a 2-3/4" prop on a #10 thread hand cut on stainless shafting, has run for 10 years.


Pat M

Oh, I thought you meant cutting threads on a lathe.

Shoot, with a die I have threaded practically everything.

Well patman, this morning I went to lowe,s and saw a chart #10 = 0.190 and I knew the 3/16th was 0.1875 so I figured when Dumas says 3/16th shaft with 10-32 thread they really mean 3/16th shaft with a die of 10-32, used to make the threads. I wanted to verify this when I got home and found you "allready" vearified this to a tee, thank you.
I have two more questians:

Do I have to use the $4.19 cutting fulid, or can I use something else like oil, ect.

Will the die stay perpendicular to the shaft due to = friction or, do I just have to be very carefull. Thanks, Randy.

Randy, you can use oil. Cutting fluid is normally used with powered machines.

Yes, you must be careful when starting the die to keep it square. Once it has threaded on a way, it should remain square but there is always the chance you can cock the die so just take it slow and keep an eye on the squareness.

Thank you patman, lows had a set for $20 with no handel. home depot for $45, and nither place sells the handel seperate, I found a new looking single 10-32 die at the flee market for $1 so know I just need a handle. I plan on trying some how using a 90 degree drafting to help me with the squareness. When I find a handel I will keep you posted on the outcome.

The whole reason for this is the ss shafts are not as straight as the brass ones and the make a raquet when the shaft is spinning.

Buy your stainless from www.mcmaster.com or www.smallparts.com ... not the rough oversize nasty stuff from the hobby shop! The good stuff is precision ground and is intended for use as shafting.

Pat M

Probably too late to help, but I use "Tap Magic" as the tapping lube. It works very well.

I found a dye handel at Ace hardware, I have threaded 3 shafts now, not to hard. I also recieved 2 more ss shafts from Dumas, the new shafts are the straightest of the 6 ss ones I have, but not as straight as the brass rods, If the brass ones are strong enough I might stop using ss ones all together, the brass ones run smoother and are cheaper. Thnnks, Randy