Making brass rod 'pointy' - can it be done at home?

[Filler]

Hello. I was just wondering if it is possible to turn a piece of brass rod, say 1mm dia, into a probe or pitot etc by filing it to a point and cutting to length. Has anyone tried this with any success, or is a lathe needed?

[RAF4EVER]

As far as I can remember,neither are pointed,they are rounded over at the end. It should be possible to file it, with a fine file. HTH

[rayprit]

Use in an electric drill and use a file or emery paper on it as it rotates until required profile is achieved

[Jamie @ Sovereign Hobbies]

I've found this (using a drill) very difficult. I don't claim to be an expert but can usually manage to work rigid materials to some degree but I've tried this a few times and have frankly just made a mess. It's hard to get much of an effect at all with abrasives without a lot of force but with any meaningful force the brass rod just bends. Worse, the further from the chuck the greater the bending moment on the area you're abrading. The upshot is that whilst it's possible to remove material, having control over it is difficult. It's also painfully slow so there's this ever present temptation to hold the abrasive more firmly against the brass. It's surprisingly easy to buckle it (mind your fingers when it goes) but you can break the rod off near the chuck too as what you're doing is applying cyclical loads and it fatigues the brass.

 

Have a go. Maybe don't expect miracles?

 

Edited January 18 by Jamie @ Sovereign Hobbies
edited for clarity

[Filler]

Thanks gents. It would be for the ECM antenna on top of the starboard tail fin of an F-15 in 48th scale, which is pointy-ish. I've caught the plastic kit part a few times and it just won't go straight again. I hoped I could get a piece of 1mm brass rod and file it, but I understood that brass is pretty hard.

 

I'll do as you suggest Jamie, have a go, be patient and don't expect much.

[Black Knight]

No need for a lathe; just use fine jewellers' files

Its easy peasy, I file down brass rod and brass tube all the time to make lacing needles for use in my leather work. It only takes a few minutes to make a length of 1mm brass rod into a sharp lacing needle

[Graham Boak]

just to add the the rod should be laid on a firm surface - modelling board - and filed along it, rotating as you go.  Check regularly to avoid forming flats.  You can use the same technique on plastic rod.

[Dave Swindell]

If you're using abrasive paper/cloth and a drill chuck or similar, fold the paper/cloth over on itself and run the rod between the fold, squeezing between your finger & thumb. That way you're supporting both sides of the rod and cancelling out the bending moment.

I'd use a file as above to rough the rod taper into shape, then finish with abrasive paper between your fingers.

[JamesP]

Same as the other advice, file rod against a board, also I suggest you hold the rod in a pin vice it makes life a lot easier

[Mike]

I've done it before by chucking a length in my Proxxon tool, pressing some sanding material against it to get it pointy, and being sure to keep the speed low so it doesn't burn the sanding material.  When it's getting to the right shape, use finer grits so it polishes to a shine, and remember to round the tip off so you don't poke an eye out once you're finished.

[Filler]

Thanks again for all the advice. I shall give it a go this evening.

[Mike]

44 minutes ago, Filler said:

Thanks again for all the advice. I shall give it a go this evening.

Make sure you give us a call from the Emergency room before you go in for surgery

 

(in other words, wear eye protection and be careful)

[Circloy]

The correct way to reduce the diameter of a round bar when using a file is actually counter to what most people believe.

 

The file should not follow the same rotation as the bar as this gives little control and is a prime cause of flats.

Instead the file stroke should start with the leading edge of the file against the bar with the handle held higher than the front edge of the file (think pointing down).  As the stroke progresses the file handle is moved lower with the handle finishing below the forward edge of the file (think pointing up).

 

The arc of this backwards rolling motion ensures the cutting edge(s) of the file are always correctly orientated to surface of the bar.

[Filler]

Well, life (aka a toddler) got in the way last night, but this morning I took a piece of rod to work and decided to have a quick play. Firstly, I didn't have 1mm rod, so have used 2mm for now, despite being too large for the intended purpose. And secondly, I am glad I didn't try at home because I have concluded that you need heavier kit than I have at home.

 

At work I have used a bench vice, a file and a battery drill and some sandpaper as pictured.

 

 

The result was very encouraging.

 

 

I can see two issues I will face when I try again after I have some 1mm rod. One is getting a smoother finish, but hopefully some finer grits of paper will help with that. You can just make out some grooves in the photo. The other issue will be if the drill will hold 1mm rod.

 

Just for context, this is what I am trying to replicate. The smaller starboard ECM antenna.

 

Thanks again for all the advice.

[Rob de Bie]

I would use a small cutting disk in a motor tool. Normal usage is to use the 'thin' edge to do the cutting, but you can also use the 'flat' sides. Hold the brass rod at a flat angle to the disc, and rotate the rod with your fingers while the cutting disk does the sanding. Easy-peasy, I do that often to round off spring steel wire.

 

Rob