Small adjustable Reamer

[AndyNC]

Hi,

Do adjustable reamers less than 1/4" exist?

I can find one that go from 1/4" up to 9/32" but not smaller.
I'm trying to make bushes for an odd size mandrel (0.246").
A Letter D size drill is to small and a 1/4" reamer to big. A 6.3mm drill may work but I don't have one and I would prefer a reamer.

Many thanks

Andy

 

[Spindle]

Hi

0.246" is 6.2484mm - link to a 6.25mm adjustable reamer:

http://www.ebay.co.uk/itm/Adjustable-Re ... 0908815468

But I'd go for one like this:

http://www.carbidenow.com/625mm-Solid-C ... 36730.html

Regards Mick

 

[Inspector]

Have you considered or are able to use a boring bar with the machines you have?

Pete

 

[porker]

Have you considered making a D bit out of a bit of silver steel? You could turn this up, mill or file the end and harden and temper. Useful to get an accurate reamed hole. Bit small to bore with a boring bar I would have thought.

 

[AndyNC]

Thanks for the suggestions.

Porker: I have some 1/4 silver steel so annealing, turning to get a nice fit, grinding to shape and hardening sounds like a nice little job.

Inspector: I don't think I have a boring bar small enough at the moment. Although I've been given a tray of tool steel so grinding one wouldn't be an issue.

Spindle: I may give these a go if the D-reamer doesn't work. The letter D drill was too small D=6.2484mm so 6.25 sounds like the right starting place. I normally ignore the sent from china items on ebay because I have heard some poor reports on delivery.

Many thanks

Andy
PS: Off on hols at weekend so no action for two weeks.

 

[Spindle]

Hi

If you're going down the drilling route 0.246" is a letter D drill bit - drill and lap will be easier than trying to take a one thou cut off of silver steel.

Regards Mick

 

[AndyNC]

Hi,

Tried the D reamer method but I couldn't anneal it well. I only have a propane torch and could only get it just red. I need some fire bricks or a little oven made from thermalite or celcon blocks.

Tried drilling and boring and had some success. I got the ID good fit but I fluffed the outer dimension. In the tray of tool steel I found a suitable cutter ground down to about 3/16 with a little nose on it. I think my father has been down this route before.

I started again and this time the D gauge drill drilled it out to a good fit. I'm not sure why but I did note that there was more swarf off one flute than the other leading me to believe that the drill was not central although I used a centre drill to start with.

At least this has got me to the second stage.
I might give the 6.25mm adjustable reamer a try.

Cheers

Andy