Are there any adjustable reamers under 1/4" ?

Chucking reamers are available in number, letter and fractional sizes, probably all metric sizes as well, so if it's critical, assuming you're willing to invest in a variety of sizes, you should be able to buy anything you need. The one concern is if the plastic in question lends itself to reaming. If it's too soft, it may not cooperate. Nylon, for example, would be a bitch to work with.

I can't imagine you'd find adjustable reamers when you get down to that size-----but I could be wrong.

Harold

According to Bruno :

How thick is the workpiece? If it is thin, and you can live with a little taper, get some taper pin reamers, and just run one in to whatever depth gives you the desired size.

Soft plastics can be reamed just a little undersized, and expanded with whatever you are fitting into it.

Brittle plastics will need to be reamed to full size, or perhaps drilled oversized and bushed.

The fact that you are adjusting the size with a file suggests that the actual precision needed is not that great -- unless you are

Good Luck, DoN.

If this is e.g. a plastic box, let me tell you a story. I grew up completely ignorant, even helpless, around tools. I was very curious, however (still am) and used to get into all sorts of jams. One time I was trying to make a little electronics project and I made a horrible botch of drilling a hole and my father-in-law, a former tool and die maker at Dodge, laughed and got out a tapered repairman's reamer. This isn't really a precision tool, this was probably the kind you'd see in a rack of tools made by General at a tool store. A few quick twists and that hole was nice and round.

I bought one right away and have had it ever since. Works just great. Here's one that costs a bit more than I remember but you can see what it looks like:

Thanks Harold, Grant and DoN for your responses.

The application is fitting nibs into sections on fountain pens so the size of the hole is dependant on the individual nib and feed used. They can vary all over the map, but the hole should be to within about a thousandth to get a tight seal. The materials are generally acrylics or hard rubber. The depth of the hole can be about an inch, although the critical part of the diameter is the area close to the top.

So, step sizes are not the best choice. A set of tapered reamers is not a bad thought since the top part of the hole can be a touch larger, and that's where the real seal needs to be.

I was just figuring an adjustable reamer would make the job easiest without buying a ton of tools.

-Bruno

Bruno wrote: