Spiral Hand Reamer Sharpening

[Runner]

Hi all,

I purchased a second hand 5/8" spiral hand reamer specifically to ream two liners (these are used in piston valve type cylinders for a locomotive) made of Gunmetal LG2 (aka redbrass). However, I am having trouble reaming one the liners, one was OK. Both liners were specified as gunmetal LG2 but the one that's proving difficult was from another supply and is visually different. My assumption is that the spiral hand reamer needs sharpening, how is this undertaken?

Thanks in advance.

Brian

 

[neseng]

Sharpening of a spiral fluted parallel reamer is not something that can easily be tackled without the proper machinery. You would need to have access to a proper tool and cutter grinder with facilities to hold the reamer between centres for a start. Then the method of setting it all up for grinding is a fairly in-depth process. There are tool grinding shops around (in Australia anyway) that can do the job but it is most likely far cheaper to simply buy a new reamer.
Sorry that I can't come up with a quick and easy way.
Cheers, Norman.

 

[Swifty]

A reamer can be made to cut slightly bigger by drawing a carbide tip along the inside of the flute, against the cutting edge, this causes a slight burr to be raised up. You can try one flute first, but if it still cuts undersized, gradually do it to more flutes until it cuts on size. Won't permanently fix the reamer, the slight raised burr will not last long, but it can get you out of trouble.

Paul.

 

[ZipSnipe]

I would think that if you are trying to get a specific size hole then trying to sharpen a reamer will not achieve this. Chunk it and buy ya another one.

 

[Runner]

Thanks for the replies. To buy another reamer is not cost effective as it is a once off need. I will never require to use it after this operation. A more cost effective solution is to buy another piece of gunmetal LG2 and make another liner. I somehow think I got a rougue piece that is particularly hard.

Brian

 

[chrsbrbnk]

You might try honing the hole out from the undersized ream with a brake hone the brass and bronze hone out pretty fast ,hone dry don't use oil

 

[Runner]

Having considered the option of remaking another liner from a more forgiving piece of gunmetal LG2, I realised that trying to remove the liner from the piston valve bore was going to be very difficult and more likely do some damage and produce more problems than I was trying to correct. So I was stuck with an unforgiving piece of gunmetal LG2 and a not so sharp spiral reamer. The ergonomics of me trying to put pressure on the reamer to force it through was not ideal, the job in the vise and an 8" reamer put the wrench about chest height so I stood on a box and was able to push down on the wrench which helped a lot. It still took me over three hours to finally succeed. I am arf glad I go to the gym twice a week. But the weights I lift are up not pushing down so I am feeling it in muscles not normally exercised.

The end result is a very good finish bore and within the limits of my digital vernier caliper (+/- 0.0005") spot on 5/8ths. I hope when I buy 5/8ths" stainless steel rod to make the valve bobbins that they will produce a good sliding fit without further machining.

Brian