Strange reamer designations

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I've bought some reamers in a job lot from the ubiquitous online auction site and some of them have strange (to me at least) writing on them. I assume that its a size thing but this is not something I've heard of before. Examples are:-
One marked IRS3/114, another IRS2/256 and a third marked MIRS2/50.
Anybody come across these before?
They're in very good condition and there are a lot of metric and imperial sizes that I recognise plus a few of these oddball ones.
 
Just a WAG but the "IRS" bit might stand for Inside Reamer Spiral (or Straight). Pictures would help.

Have you measured them?

Craig
 
Here's photos of one of them. It measures 16mm as close as I can measure it without taking it to the garage, so a cheap digital caliper's opinion. The manufacturer is Presto, a well known brand at least in the UK, and the markings are HSS (I think I guessed what that bit means) 1RS3/114.
Its a parallel reamer having little to no difference between the end diameters. I was expecting a small lead in taper but nothing measurable with the poor kit.
I wondered about a Presto internal part number but the Google is not very helpful in that direction.
Not for the first time, I'm baffled.
Reamer1.jpg
Reamer2.jpg
 
The reamer is a spiral and that looks like a Morse taper 3 shank so that might account for the RS3 portion. Maybe.

16 mm is also very close to 5/8 of an inch so a more precise measurement is probably needed. In addition, reamers are commonly available in over-size and undersize variants to help achieve a sliding fit or a press fit.

Weird, though, that a company would sell a reamer without marking the size on it somewhere.

Craig
 
Here's photos of one of them. It measures 16mm as close as I can measure it without taking it to the garage, so a cheap digital caliper's opinion. The manufacturer is Presto, a well known brand at least in the UK, and the markings are HSS (I think I guessed what that bit means) 1RS3/114.
Its a parallel reamer having little to no difference between the end diameters. I was expecting a small lead in taper but nothing measurable with the poor kit.
I wondered about a Presto internal part number but the Google is not very helpful in that direction.
Not for the first time, I'm baffled.View attachment 153990View attachment 153991
Odds are they from manufacturing.
When I do a lot one size I would the reamer ground to size I need for perfect fit.

Dave
 
Odds are they from manufacturing.
When I do a lot one size I would the reamer ground to size I need for perfect fit.

Dave
Well that's just the one I need, the one that gives me the perfect fit! And I've got half a dozen of them.
I'll measure them up in mm and inches this weekend when I've got time as I'm still puzzled and that sometimes leads to fascinating things.
 
...looks like a Morse taper 3

16 mm is also very close to 5/8 of an inch

You must be looking at a different photo to me. If you can recognise the 16mm diameter of the flutes, how do you arrive at Morse taper 3 for the other end?

The picture I see has the large end of the Morse taper approximately the same size as the flutes. A Morse taper 3 has the large end 0.94", which is considerably larger than 5/8".
 
Maybe they are specials, made for a specific customer ?
It is specs for grinding that done to reamer.
I had book on numbers and letters on what said. About all I know.

All I know if I see that group numbers and letters the ream is a drawer filler. I got some at a auction in pass and money was better spent on buying correct reamers

Dave
 
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All I know if I see that group numbers and letters the ream is a drawer filler. I got some at a auction in pass and money was better spent on buying correct reamers

Dave
The money I spent on the whole lot wouldn't buy a single reamer at the reamer shop. I'm very happy that most of them, around forty, are in good condition and are marked up in the normal manner with size and tolerance specs, but these few are outliers. At a dollar each, you'd struggle to argue that money was squandered here. The next expense will be housing the things as they're spread out all over my office at the moment.
It's beginning to look like these are specials, made to a customer's spec., by Presto and Dormer. These aren't no-name brand things. Probably a different measuring system used by space aliens or something.
I found what could be a third party logo on a couple, maybe it means something to someone on here?Reamer3.jpg
 
A friend of mine used to drive a garbage truck and was a real "Picker" if he would see something that looked fairly decent he would keep it and then have a big barn sale a few times a year. He made a lot of extra cash selling garbage.
One day while picking up a roll off container from "Moen" ( the faucet company ) here in Ohio, he saw a big steel drawer full of reamers and taps and snagged it for me. They all had strange markings on them like your reamer shows, they also all had a "Cleveland Twist Drill" logo on them, also a local company. My guess was they were marked for a specific job. Probably a call out from the prints. I also guessed that it was a faucet that they decided to stop making and tossed the old tooling. They were all in great shape, but not one of them was a normal size.
Probably a similar situation for yours. Just a guess.

Scott
 
Presto are still trading, why not email them the details and see if they can tell you what the numbers mean. Their website is https://www.presto-tools.co.uk/
Just a thought.
Just fired them off an e-mail as I would have if I'd been clever enough to think of it. I'll pass on any info that they can supply.
 
I have bought tooling in the past from factory closure auctions , some was standard sizes but often the tools had been made specifically for the company and to a non-standard size.
Dan.
 
I'm waiting for the reply from Presto but I'm also intrigued by why a manufacturer would go to the effort, and I assume added expense, of going with a non-standard size. I'm not familiar with production engineering of machine shop parts, but surely it would be easier to buy in standard reamers (and other cutting tools) rather than ask a tool making company to make me a special run of tooling. Even in the "on no, we need a new reamer as we've run out, run to the shop and buy one", "can't do that, it's a special", "expletive", it makes little sense to me.
Maybe there's a logic to it that i can learn here.
Sorry I didn't get to measure the thing properly, I got caught up repairing my shaper top slide, which was a learning curve in itself.
 
I am a manufacturing engineer--retired
It is very Normal for shops/companies to have custom reamers for their products
Some of the reasons are. Special lubrication clearance ( due to load or RPM)
Engineering designs that never take standards into consideration of design ( Been there on the receiving end ). Holes that will go through heat treatment and change size . Press fits of components need exacting fits. and on and on
Usually the reamers (Or Taps , or endmills or C'Bores ) have a "process number" where the blue print will not even say " .2345" hole-ream" but instead say "Use 76RT reamer to size" on the print and BOM so that the machine shop is compelled to that exact size, and one that the engineering department has the liberty at a later date to change .
And realize when they do make a change, all the old reamers, even brand new....are scrapped to prevent errors
Rich
 
I am a manufacturing engineer--retired
It is very Normal for shops/companies to have custom reamers for their products
Some of the reasons are. Special lubrication clearance ( due to load or RPM)
Engineering designs that never take standards into consideration of design ( Been there on the receiving end ). Holes that will go through heat treatment and change size . Press fits of components need exacting fits. and on and on
Usually the reamers (Or Taps , or endmills or C'Bores ) have a "process number" where the blue print will not even say " .2345" hole-ream" but instead say "Use 76RT reamer to size" on the print and BOM so that the machine shop is compelled to that exact size, and one that the engineering department has the liberty at a later date to change .
And realize when they do make a change, all the old reamers, even brand new....are scrapped to prevent errors
Rich
And, because there is no size, just a '76RT' designation, they can't even be checked with a CMM? I would think someone ought to know the dimensions.
 
I have some such reamers in my tool box that were picked up years ago at a garage sale or auction.
I estimate the size and drill a slightly smaller hole in some aluminum plate ( 3/8-1/2 ") and then carefully ream the hole and measure it and then put a tape wrap with size on the shank.
You want the work piece thick enough to use a telescopic gauge for measurement
Rich
 

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