Model Engine Maker

Help! => Machines, Tools and Fixtures => Topic started by: Alyn Foundry on August 24, 2021, 11:50:32 AM

Title: Small round bar end finisher.
Post by: Alyn Foundry on August 24, 2021, 11:50:32 AM

Good morning.

A year or so ago I managed to find on eBay listings, mainly from outside the UK, of a simple tool to create a clean looking half round end to a rod. I’m now needing such a tool to quickly clean up the sawn ends of 4 mm CZ 121 Brass rod. I would ideally like to have the tool rotating and to be able to hand finish the rods against it. Despite many tries of different descriptions in their search engine, the “ D cup cutter “ was highly illuminating  :o I’ve drawn a blank, can anyone help please?

Whilst on the subject of help I’m also looking for 1/4” Whitworth half chamfered Steel nuts.

Cheers Graham.

Title: Re: Small round bar end finisher.
Post by: Jo on August 24, 2021, 12:02:13 PM

I am assuming you are thinking of something like an electric pencil sharpener where you poke the pencil/bar in and it munches the end.

I wouldn't want to be hanging on to the end  :noidea:

Jo

Title: Re: Small round bar end finisher.
Post by: Alyn Foundry on August 24, 2021, 12:29:17 PM

Quote from: Jo on August 24, 2021, 12:02:13 PM

I am assuming you are thinking of something like an electric pencil sharpener where you poke the pencil/bar in and it munches the end.

I wouldn't want to be hanging on to the end  :noidea:

Jo

Hi Jo.

Well, yes and no. The tools I found, their name escapes me at this moment were effectively an internal Burr, semicircular and available in different diameters. Lots of USA listings.

Cheers Graham.

Title: Re: Small round bar end finisher.
Post by: Jasonb on August 24, 2021, 12:54:32 PM

plenty of old nuts here https://historicthreads.co.uk/nuts-7-c.asp

I've seen the rounding tools used to finish off rivits to look like stays.

Title: Re: Small round bar end finisher.
Post by: Jasonb on August 24, 2021, 01:18:27 PM

Cup burrs

https://www.eternaltools.com/cup-burrs

Though 4mm seem hard to find.

Have you thought of using a 2mm rounding over milling or router bit held in the toolpost and just using it as a form tool against work in the lathe?

Title: Re: Small round bar end finisher.
Post by: Alyn Foundry on August 24, 2021, 01:26:35 PM

Thanks Jason.

Aye, Cup burs….

However, only available up to 2.5 mm. I found this listing from the States.

https://www.ebay.co.uk/itm/192593226266?hash=item2cd7736a1a:g:OIgAAOSwIrVbQrEv

But the postage sounds way in excess of reasonable don’t you think?

No post war 1/4” Whitworth nuts either.

Cheers Graham.

Title: Re: Small round bar end finisher.
Post by: Jasonb on August 24, 2021, 01:38:26 PM

Heritage Steam do post war but only down to 3/8"

Historic will do specials but may be expensive unless you need a lot, they CNC cut them from round bar.

I did see an Amazon listing for a set of the cup burrs that went upto 5mm but not currently available.