Help with adjustable reamer

Although I'm a novice to metalworking I recently decided to build a project out of aluminum and bought a set of inexpensive adjustable reamers when I found that I couldn't drill a hole accurate enough for my needs.

I've never used one of these reamers or even seen someone else use one. I found some good information and instruction in this group and elsewhere on the net but I've been unable to find the answer to one very basic question - Which way do you turn the reamer? Clockwise or counter-clockwise.

What little I've found concerns chucking reamers and seems to indicate that they turn in a clockwise direction. When I try this with the hand reamer it chews into the work and I can't keep it straight.

On the other hand, if I turn it counter-clockwise, it stays straight but it's very slow and I have to use alot of downward pressure on it to get it to work. If I was working with steel I don't know if it would work at all.

I guess counter-clockwise is correct but I'd sure like someone that knows to confirm this for me.



Reply to
Jim B
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No, clockwise, if you are standing behins the drill motor, looking at the hole. But, you are probably taking too much material off in one pass. Normally, you want to take off .007" on the diameter, at the most, in one pass. If you take off too much material, you get tearing instead of smooth cutting of a very thin shaving off the ID of the hole. This can be a problem if the hole came out rough or not straight.

Also, these reamers are really best used in a drill press or milling machine, so the spindle can keep the reamer straight. These machines also make it easy to keep a steady slow infeed on the reamer. it is a LOT harder to do this freehand with an electric drill, which you may be trying to do.

It is not clear what you mean by drilling a hole accurate enough. A reamer won't improve hole location, it will follow the existing hole. If your problem is diameter, roundness or straightness, then the reamer can clearly help.


Reply to
Jon Elson

This is the reliable way to make them kaputt.


Reply to
Nick Müller

Jon, I get the idea he's talking about *hand reamers*, which do not respond well to being machine driven. In the hands of a novice, it would surely spell disaster.


I can't help but think that you're talking about hand reamers (they have a square drive, and are tapered). If so, you'd be well served to use them in a drill press or mill, piece clamped in correct position under the chuck, with a center following the hand reamer while it's being turned with an adjustable wrench or T handle of sorts, manually, not under machine power. Do *NOT* use an adjustable wrench if you don't have a center following the reamer, keeping it in line and preventing tipping. Lubricate well with kerosene, or a good tapping solution for aluminum. A light cut is preferred. Don't try to take much out of the hole with the pass. Turn the reamer(s) clockwise, as you stand behind the reamer. Turning it counter clockwise will ruin the teeth, especially in steel. Could be even aluminum has dulled it by turning it backwards. Look at the teeth where they contact the work. If they have a tiny, shiny radius instead of a sharp edge, the reamer(s) won't cut worth a damn. The edge is already gone. They must be sharpened with a cutter grinder, they can't be done by hand.


Reply to
Harold and Susan Vordos

The only adjustable reamers I've seen have been for hand use, they've got a square on the driving end. There's a number of different types, if you've got the common(and cheap) import ones with two threaded sleeves and a number of moving blades, they need a bunch of tuning before you can get good work out of them. Typically you'll get 3 blades that cut, maybe one that scrapes a little out and the others will just be along for the ride. They will tend to chatter when they're like this, the only solution I've found has been to selectively stone down the ones that cut until the others also cut. Takes a lot of patience and you have to get the blades back into the same slots. I've never used one under power, I'd suspect that the body would tend to disintegrate on the smaller numbers. I've found that a half-thousandth is about the max cut I want to make with one, more than that and it tends to either chatter or bind up. An expansion reamer isn't a precision tool, but it can improve the surface finish of a hole to a tolerable degree and will take that last little bit out where you need a close fit. Don't expect it to improve the accuracy of your hole location. I like to use them in the lathe after boring a hole, locking the headstock and using a T-handled tap wrench between the hole and the talestock with a center in it.


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