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Reamers

pjf134

Aluminum
Joined
Nov 12, 2010
Location
west pennsylvania
Reamers!!!

Maybe the same reason why you should not use threading dies under power. It was more than likely not made for higher speeds, only for hand use, may break off in use. Just my .02 cents. If you feel the need, go for it and let us know the results.
Paul
 

jhruska

Titanium
Joined
Jul 5, 2009
Location
Munster, In. USA
The flutes are not concentric to the shank you will chuck on. Yes you can use them, they are made of high speed steel, but expect run out, mishapened holes, rough finish, cutting on only some of the flutes ect ect bla bla bla.
Regards,
John
 

wawoodman

Hot Rolled
Joined
Jun 23, 2006
Location
Seattle, WA
The flutes are not concentric to the shank you will chuck on. Yes you can use them, they are made of high speed steel, but expect run out, mishapened holes, rough finish, cutting on only some of the flutes ect ect bla bla bla.
Regards,
John


Are they made in some different way from chucking reamers? (I'm not arguing, I really want to know.) I bought a bunch of hand reamers; pretty much a full set from 1/2 - 1. Should I expect those same results if I ream by hand?
 

mcruff

Stainless
Joined
Mar 22, 2004
Location
Albertville, Alabama
The flutes are not concentric to the shank you will chuck on. Yes you can use them, they are made of high speed steel, but expect run out, mishapened holes, rough finish, cutting on only some of the flutes ect ect bla bla bla.
Regards,
John

Don't know where you heard this but its not true.
Hand reamers have the flute geometry ground to make it easier to use by hand, meaning less effort. They can be used in a machine under power but some of them depending on the type will acually try to feed themselves. If you use them under power run them slow compared to machine reamers.
 

jhruska

Titanium
Joined
Jul 5, 2009
Location
Munster, In. USA
I would not say that I heard that hand reamers are not ground concentric to the shank. it is more like a twenty-five years in the trade thing.
Another difference between a hand reamer and a machine reamer, no center for regrinding.
Regards,
John
 

mcruff

Stainless
Joined
Mar 22, 2004
Location
Albertville, Alabama
I would not say that I heard that hand reamers are not ground concentric to the shank. it is more like a twenty-five years in the trade thing.
Another difference between a hand reamer and a machine reamer, no center for regrinding.
Regards,
John
Technically no center mark on most of them but in 30+ years of using tools in the trade (Tool & Mold Maker) I have never seen a hand reamer that did not have a center point at least. I was told when I was an apprentice thats how you identified a hand reamer was by the point on the tip. That point is how the reamer was accurately held to grind the flutes and to size it. In this day and age, hand reamers do quite a bit of the time have a center dimple for holding them between centers. Check out this link.

http://www.icscuttingtools.com/catalog/page_196.pdf

Old hand reamers as in woodworking or blacksmith work may not have been concentric or precision but everything I have used made from the 50's on was as accurate as a machine reamer.
 

jhruska

Titanium
Joined
Jul 5, 2009
Location
Munster, In. USA
Dang, did not check my own source, my brain. Went thru my hand reamers and they said I was wrong.
I use a lot of the smaller taper pin reamers and they have no center hole and the shank is not concentric.
John
 

jdleach

Stainless
Joined
Sep 19, 2009
Location
Columbus, IN USA
After spending a lifetime in the trade using reamers, both hand and machine extensively, I just had to reply to this query.

As for identification, this is easy: Every machine reamer I have ever seen has had a straight plain shank, or a taper (Morse, Brown and Sharpe, Jarno, etc.). A very few will have two small flats on the end, and another small number will have notches, grooves, or channels for connecting to special holders. All, and I mean ALL, hand reamers I have ever seen or owned (and I have got shelves of the things), have the end of the shank squared like a tap. This is so that, surprise!, you can use a tap handle to drive them.

In regards to construction, there is also some very easily discernable differences. Machine reamers almost uniformly are not adjustable. There are some rose head reamers and chucking reamers that may have a tapered screw in the end to "splay" the tip and therefore adjust the size, but the vast majority are ground to a specific diameter, and are only adjusted by re-grinding.

By the same token, hand reamers are pretty uniformly adjustable. There were more solid hand reamers produced in the early part of the 20th century, but most, if not all, hand reamers for the past several decades have been of the adjustable variety (Victor Machinery Exchange has a large inventory of solid hand reamers, but I suspect they are either imported, or NOS). The majority of adjustment is done in one of two ways: The most common is of the compression, or integral flute style, where the reamer head is bored hollow, the teeth are ground in, and the interstices between the teeth are then slit over their entire length. An long adjusting screw is then installed such that when tightened, it "squashes" the shank end and the reamer tip together, thus bulging the middle area of the flutes.

The second style, employs a wedge system that when tightened, forces independent blades outward. This to me, is the better reamer because the blades are not only replaceable, but can be easily removed for sharpening on a surface grinder. The downside of this type is that the reamer body can develop wear in the slots in which the blades sit that can allow wobble and cocking. This of course, causes all manner of problems to the hole as far as size, finish, etc.

To address the original question: Why can you not use hand reamers in a machine? The short answer is that you can, but you have to proceed very slowly and carefully (I will not use a hand reamer in a machine). By definition, and reference the above construction details, hand reamers are less able to withstand the forces generated by a machine (not being solid, less robust). They are much less rigid by design. Also, the way in which hand reamers are ground, and the way they cut, differs markedly from machine reamers. A machine reamer, although chamfered on the end to permit starting in the hole, cuts at the tip, and is ground with a very shallow taper toward the shank (gets smaller). Hand reamers have a very shallow lead-in toward the middle of the flutes, then tapers back down toward the shank. This permits easy starting, and less chance of cutting off-center.

Finally, all (good) machine reamers are ground with uneven flute spacing. In other words, the distance between each flute is staggered by differing amounts. This greatly reduces chatter and a wavy surface in the hole. Some hand reamers have evenly spaced flutes, as the speed with which you can spin the tool is much slower than your average lathe or drill press, and thus chatter is not near as much a problem.

In a nutshell, hande reamers cannot remove as much material, withstand near the torque and RPMs, or last as long as a machine reamer when used under power. Too, the longer lead-in generates more heat under power due to the scraping action in a hand reamer versus the cleaner cutting action of a machine reamer. The results can be binding, and an oversize hole.

J.D.
 

wawoodman

Hot Rolled
Joined
Jun 23, 2006
Location
Seattle, WA
JD,
Thanks for the detailed, and highly informative answer. I think that gives me what I need to know. Thanks to all who chipped in! :cheers: :bowdown:
 

trevj

Titanium
Joined
May 17, 2005
Location
Interior British Columbia
The post above by jdleach covers adjustable hand reamers nicely, but does not cover the geometry that is the real difference between a machine reamer and a hand reamer.

A machine reamer has a short, usually 45 degree angled edge that does all the cutting. A hand reamer has a very long slow taper that does the cutting. If you use one in a lathe it ends up with a huge engagement of cutting edge and rapidly costs you both your reamer and your part.

If you look close at the cutting edge of an adjustable hand reamer or any other hand reamer you will find that there is a very distinct taper on the working end, up to the full diameter a ways down the blade edge.

All the talk of uneven spacings etc is there, but matters not much to anyone but the tool and cutter grinder that may have to make one from scratch.

Machine tools on machines, hand tools by hand. Saves wreckage.

Give some thought to whether a maker of any decent quality tool would purposely make it not concentric. It would just add a bit more misery to trying to make a living. You can bet your last buck that they were trying to make it as concentric as they could.

As for the missing centers. It depends on the machine used to make the tool. That about covers that. Lots of reamers ground with a male center pip on them, lots have centers, both hand and machine. Some don't. It's a red herring. Nothing to do with whether it's a hand or machine reamer.

Hope the link works. Machine shop practice - Google Books

The "Starting Taper" shown in the figure, is the way to ID a hand reamer. Figure out how much more of a cutting edge is involved, and ask yourself if you feel lucky. :)



Cheers
Trev
 

trevj

Titanium
Joined
May 17, 2005
Location
Interior British Columbia
Yes. Yes you do. :)

Those two books and a copy of Technology of Machine Tools by Krar et al, are a pretty solid foundation in the basics of 'How to'.

For a relatively new machine tool user, they represent a great deal more value than Machinery's Handbook or similar books, which are really just the mother of all wall charts in book form, rather than providing 'How to' info or explaining.

Cheers
Trev
 

Paul Farley

Aluminum
Joined
Dec 29, 2006
Location
Sequim Washington
X-2 On the book selection. The book by Krar was my text in College in the 70's.
But still a great referance. The set Machine shop practice is available from Amazon.

Great referances!
PaulF
 

Marty Feldman

Titanium
Joined
Feb 21, 2005
Location
Owl's Head, Maine
As with most subjects he covers, I find that Moltrecht provides a clear and detailed description of the two reamer types and makes understandable the difference in their usage. Aside from the square at the shank end of most hand reamers (for holding in a hand reamer holder), the shank form has nothing to do with it. In differentiating between the two reamers, the primary focus should be on the cutting tip where the reamer contacts the hole to be reamed - relatively long starting taper on hand reamers, short chamfer length on machine reamers.

-Marty-
 

animal12

Cast Iron
Joined
Apr 9, 2009
Location
CA USA
Looks like those books are available over on PDFDRIVE
animal
 








 
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