instructions for adjustable reamers

Below is my transcription of the instructions which came with an old set of expansion reamers. The original document was much creased, stained, and missing
in places, but I was able to get a scan and read all the text and type it in. I'm responsible for any typos. I will post the original scan (622k) if requested. - GWE
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CRITCHLEY TYPE REAMERS Size Range of Expansion Length of Blades Length Over All A 15/32" to 17/32" 2" 5 1/4" B 17/32" to 19/32" 2" 5 3/4" C 19/32" to 21/32" 2 1/4" 6 1/4" D 21/32" to 23/32" 2 1/4" 6 3/4" E 23/32" to 25/32" 2 1/2" 7 1/4" F 25/32" to 27/32" 2 1/2" 7 3/4" G 27/32" to 15/16" 3" 8 1/4" H 15/16" to 1 1/16" 3" 8 3/4" I 1 1/16" to 1 3/16" 3 1/2" 10" As indicated, each reamer expands to the smallest size of the next larger reamer, thereby eliminating many odd sizes which would otherwise be necessary.
------------------------------------------------------------------------------ CARE OF THE REAMER
When adjusting the reamer, care should be taken to see that the nuts are not drawn too tightly, just firmly against the collars.
The nuts should never be given more than one full turn for each cut, but should be turned sufficiently to make it cut. If it doesn't cut it will burnish the surface of the hole and dull the reamer.
In sharpening the reamer the clearance should be kept about the same. The landing or circular ground edge along the front of the blades should be about one-hundredth to one sixty-fourth of an inch wide.
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INSTRUCTIONS
Best results can be obtained by taking shallow cuts, testing after each cut with the pin to be fitted.
If two or more holes are to be reamed to the same size, as for piston pins or king pin bushings, best results will be obtained if all holes are reamed after each expansion of the reamer. Then expand the reamer for another light cut and follow through all the holes again. Continue this until the desired size is reached. When the final cut is taken all the holes should be uniform in size.
In reaming cast iron, bronze or brass there should not be any oil used, the dryer the surface, the nearer perfect bearing and perfectly round hole is obtained. In using oil the reamer will cut the smoothest looking hole, but will give you from 25 to 40% less bearing.
In reaming steel it is very important to use a good thread or screw cutting oil.
Aluminum is about the most difficult metal to ream, and it is practically impossible to ream it dry. About the best results can be obtained by the free use of kerosene.
The work should be held stationary in a vise and the reamer turned with a double end wrench, such as a tap wrench or any kind of wrench that will give equal leverage on two sides. It is just as nearly impossible to ream a good hole by driving a reamer with a single end wrench as it is to drive a tap with a single end wrench. If the reamer is held in a vise and the work turned over the reamer by hand it will very often cut the hole rough and too large on the end the reamer is started from, and sometimes larger on both ends, especially on work where the hole is not exactly in the center, which throws more weight on one side of the reamer than the other. For instance a connecting rod, it is practically impossible to hold such a piece so that the weight against the reamer will be the same on both sides. The heavy end will be lifted either too high or not high enough.
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Thanx, Grant! I printed it out to keep with my reamers.
Bob Swinney

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Thanks Grant! Printed and laminated!

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Thanks for the printout! It reinforces what I had already learned about hand reaming. Nice gesture. Bugs
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Great; best description I've ever read about hand reaming. Don't forget this hard-learned axiom as well: "Don't ever, under ANY circumstances, turn your reamer counterclockwise. Doing so, with anything harder than plastic, will immediatly turn over your cutting edges and you'll be forced to resharpen. This is true even when removing your reamer to adjust for the next pass." dennis in nca
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<snip>
Interesting stuff. I take it this was for the kind of adjustable reamer with invidual blades, and opposed nuts at top and bottom?
Jim
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jim rozen wrote:

Yup.
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Very helpful.
Thank you.
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