Another adjustable hand reamer question - setting to known size

[Arthur.Marks]

Not wanting to hijack, so started another thread... Can comments be made on setting them to a specific size? For example, if you need a 16mm reamer but don't have one. If you have the adjustable reamers, what are some good ways to set it? I recently had this exact issue and could neither get a repeatable size using my micrometer over the opposing flutes (due to the small blades, clearance angularity of the blades and my friction thimble). Is it best to use a V-Anvil micrometer? As in, the one that still has a flat faced, movable measuring rod but the anvil rest is a V-shape... or set up some gage block configuration in leu of a ring gage (which I don't have on hand)?

[Davidhcnc]

You would have to ream a hole and measure the hole.

[DATo]

For odd sizes you might try making a ring gage by boring it to size. If you want to get real fussy you might make a male go/no go gage to test the ring gage first. Then set the expansion reamer till it just barely slides through the ring gage without taking any material off. See my post in the other thread.

[Carld]

I never had much luck measuring an adjustable reamer. drill a hole under what you want in some scrap and ream it out .001" at a time until it's the size you want and your there. BUT, that won't work for most applications and the reason is an adjustable reamer won't take more than a .001" at a time easily and sometimes not that much.

An adjustable reamer works best to sneak up on the size hole you want, not cut it in one pass like a fixed reamer does.

[elf]

I never had much luck measuring an adjustable reamer. drill a hole under what you want in some scrap and ream it out .001" at a time until it's the size you want and your there. BUT, that won't work for most applications and the reason is an adjustable reamer won't take more than a .001" at a time easily and sometimes not that much.

An adjustable reamer works best to sneak up on the size hole you want, not cut it in one pass like a fixed reamer does.

Unless you use one for roughing and another for the finish cut.

[jungle_geo]

A process that I have used (with success) to set adjustable reamers to very precise size is as follows:
Clamp the reamer by the square end in a vise to hold it.
Almost all my adjustable reamers have an even number of blades so no fancy anvil micrometer is necessary, but using one might be nice and make the job easier. For the odd blade count reamers you pretty much need an anvil micrometer or a ring with the correct inside size.
The first two thirds or so of the reamer is tapered. The last third of the reamer has essentially no taper to it, so do all your measurements at this end. All mine came from the factory with this characteristic and when I re-sharpen them I maintain that profile buy taking two separate passes on the T&C grinder. Knowing this only measure on the aft end of the reamer. The cutting edges have back rake (relief) on the cutting edge so you need to align the anvils of the micrometer to the very tip of the cutting edge, such that both anvils touch at approximately the same relative location on the anvils. Such as center-center, left edge-left edge, etc. You want to be fairly close on this alignment as any large mis-alignment will cause you to read to an erroneous value. This is probably the hardest part, but once you get a feel for it, it goes pretty fast.
Continue to adjust both nuts of the reamer until you get to size or just under by one or two 0.0001.

Like others have stated, adjustable reamers are designed to be used by hand and only take a 0.001 or even 0.0005 per pass.
I have attempted to use them to take a deeper cut and using power. I might have just as well thrown the reamer in the trash as it twisted and snapped the shaft. I then repeated with a depth of cut around 0.001 and merely just twisted the next reamer into junk. So I have really learned to never use them under power after all they are a type of hand reamer.

[Carld]

Elf, taking only .002" out of a drilled hole with two reamers would hardly clean up the rough drilled hole. Usually it takes about .005" to clean up the hole so it looks nice and then you go for the size you want.

I only tried to power ream with an adjustable one time. After I got all the pieces out of the hole I got another reamer and finished the job. Great learning experience to never repeat.

Since the reamer is adjustable I have seen no reason to "set" it to a size. I drill the hole under size as close to .010" as I can get and adjust the reamer so it will slip into the hole. Then I release the rear nut 1/4 to 1/2 turn, tighten the front nut and ream the hole. I repeat that process until the hole is the desired size.

Now if you have 5 or 10 reamers of the same size range you could set each one to be .001" bigger than the last and ream the hole in steps but I see no use in multiple adjustable reamers used that way.

[becksmachine]

Ok, I am going to try a little different perspective on this powered vs hand driven point.

As tony says in a related thread, I have also reamed a number of 206 sided holes twisting said reamer with a tap wrench and even occasionally, (gasp!! ) an adjustable crescent wrench. (At least I didn't use a pipe wrench ). It is extremely difficult to hold the assemblage square to the hole, especially if the hole is short in relation to it's diameter. This is where jugs tip (in that related thread) is very relevant, use something besides your hands and arms to align the reamer to the hole, like a milling machine or drill press.

I do heartily agree with the caveat that adjustable reamers are best used at small depths of cut, .0005"-.003" in bronze and cast iron, even less in steel. But I have had good success using a light touch under power at these settings. The tough part is being absolutely positive that this is the amount you will be removing. Usually takes a lot of patience and more than one pass cutting air to make sure all the high spots are gone.

Another trick to reaming success is to use the reamer with it's respective, optional at extra added cost, pilot and tapered bushing. This will greatly facilitate keeping the reamer square with the hole, when the hole is long enough and clearances allow.

Also when reaming a number of holes to the same size, don't sneak up on size for the first hole and then assume the reamer is set to the proper size and then proceed to ream the rest of the holes at that setting, assuming the reamer to be properly adjusted to cut the correct size. It has been my experience that removing .003" will make the reamer cut differently than removing .0005", usually making those subsequent holes oversize.

Dave

[tdmidget]

Ok, I am going to try a little different perspective on this powered vs hand driven point.

As tony says in a related thread, I have also reamed a number of 206 sided holes twisting said reamer with a tap wrench and even occasionally, (gasp!! ) an adjustable crescent wrench. (At least I didn't use a pipe wrench ). It is extremely difficult to hold the assemblage square to the hole, especially if the hole is short in relation to it's diameter. This is where jugs tip (in that related thread) is very relevant, use something besides your hands and arms to align the reamer to the hole, like a milling machine or drill press.

I do heartily agree with the caveat that adjustable reamers are best used at small depths of cut, .0005"-.003" in bronze and cast iron, even less in steel. But I have had good success using a light touch under power at these settings. The tough part is being absolutely positive that this is the amount you will be removing. Usually takes a lot of patience and more than one pass cutting air to make sure all the high spots are gone.

Another trick to reaming success is to use the reamer with it's respective, optional at extra added cost, pilot and tapered bushing. This will greatly facilitate keeping the reamer square with the hole, when the hole is long enough and clearances allow.

Also when reaming a number of holes to the same size, don't sneak up on size for the first hole and then assume the reamer is set to the proper size and then proceed to ream the rest of the holes at that setting, assuming the reamer to be properly adjusted to cut the correct size. It has been my experience that removing .003" will make the reamer cut differently than removing .0005", usually making those subsequent holes oversize.

Dave

+1 especially on the sneak up. It seems that some here expect the reamer to cut on the side. The side finishes. The leading edge cuts.

[J Tiers]

Dunno about an added cost bushing etc..... that sounds like some sort of add-on.

I DO have some of the type with a long INTEGRAL pilot portion, and matching tapered bushing. Those give almost NO trouble, and are the best type to use, if you can find them.

As for being limited to 0.0005 per pass, whatever winds your boat.... I have used these reamers for everything from a couple thou to 0.030 at a pass, depending on needs and material.

As far as I know, I have never run into a "206 sided hole".

Maybe yours have loose blades, sloppy in the slots..... dunk them in heavy oil and leave out to "dry" for a while.... or use grease. Mine are not super clean, and that might be the secret.