What are these tapered end mills used for?

crossthread · Jun 9, 2019

I bought a Craftsman wooden machinist tool box full of tools at a yard sale and there were these reamers in one of the drawers that I can't quite match up with anything in my catalogues. Some of them are very small as you can see from the six inch rule. They have quite a high helix as well. Any idea what they would be used for? Thanks.

Technical Ted · Jun 9, 2019

They look like taper pin reamers to me.

Ted

The real Leigh · Jun 9, 2019

crossthread said:
Any idea what they would be used for? Thanks.

As Ted mentioned, they're taper pin reamers.

They're used to open up drilled holes to fit taper pins.
You drill a hole slightly smaller than the small end of the pin, then ream it to size.

The reamers and the pins are still readily available.

Those are very popular for attaching items like handles to shafts.
Monarch used them all over the place on their lathes.
They're very reliable, staying securely in place for many decades if seated with a gentle tap.

- Leigh

MrStretch · Jun 9, 2019

Taper pins have been used for centuries by clockmakers. The classic 5 sided tapered cutting broaches have the same taper as the pins. One can also make a suitably tapered hole in a piece of steel by pushing a rat tail file into the hole whilst rotating it counterclockwise so that it cuts without jamming. An old clockmakers trick.

crossthread · Jun 9, 2019

Thank you very much for the information.

4GSR · Jun 9, 2019

If you do any machine building or repair, they are a must and a life saver! I have a collection of them in one of my machinists tool chest for the repair and rebuilding I do. Hang on to them! you will need them one day, I promise you! They should be numbered from like 0000 for the small ones to up over 6 for the larger ones. They even go higher than a No.6, just don't look like any in the pictures. Also have metric version of them that are on a slightly different taper and I'm not familiar with their destinations. Don't recall running into any either, of course, I don't own any Asian built machine tools in my shop, yet.

L Vanice · Jun 9, 2019

Specifically, the picture shows machine (powered) taper pin reamers. There are also hand taper pin reamers with a square on the end. Each type has its own best applications.

Larry

crossthread · Jun 9, 2019

Thanks again.

ratbldr427 · Jun 9, 2019

The spiral reamers are RH with a LH spiral.They require more pressure to cut than the straight flute reamers and the swarf is pushed forward.
The imperial reamers have a 1 in 48 taper;Metric have a 1 in 50 taper.

Imperial reamers are numbered and you have to look at a chart to find the dimensions. Metric are sized by the small end;a 6 mm is six mm on the small end(where as a #6 Imperial much larger),a long enough metric reamer will overlap to the next size.

I stock the longest size metrics in each size since I usually have to cut them to match the original or re ream the hole for a longer pin.

By reaming the size hole in a piece of scrap round stock that you are working with,you can tap the pin you are using in and then chuck and machine the ends the correct length and put internal or external threads on if needed.

We used to have a lot of older American made equipment with Imperial pins however in the last 10 years just about everything I have worked on has been metric.

EPAIII · Jun 9, 2019

That seems to imply that rat tail files have a standard taper.

MrStretch said:
Taper pins have been used for centuries by clockmakers. The classic 5 sided tapered cutting broaches have the same taper as the pins. One can also make a suitably tapered hole in a piece of steel by pushing a rat tail file into the hole whilst rotating it counterclockwise so that it cuts without jamming. An old clockmakers trick.

Cobranut · Jun 9, 2019

My Rambaudi Mill has this type of pin in several spots, notably a threaded one that locks the head at 90 degrees. You tap it home, and use the nut threaded on the end to pull it out when you want to tilt the head.
I like to never got one out that retained the handle on the shaft of the table power feed, until I figured out it was tapered. It was in a difficult to see spot. It was flush at each end, and I couldn't really see the difference in diameter at the ends and I was pushing it the wrong way. LOL

GregSY · Jun 9, 2019

Where are all these garage sales with toolboxes full of tools? Around here, all you get at garage sales are candles, hot glue guns, stuffed animals, and old trophies.

juergenwt · Jun 10, 2019

Those are most likely a die makers taper reamers. They are used to cut a die taper on the bottom of a perforating die so the slug can fall out and not jam the hole in a die block. If the were taper reamers for taper pins than they would be marked with the taper like 1:50 for metric or Taper/ft for imperial and would most likely have only a slight twist or none at all. Very few individual people would own a set of taper pins. Most likely they would be part of a shops equipment. I think you got the priced toolbox of a retired
Tool and Die Maker.
Taper reamers for die clearance - Google Search

Tyrone Shoelaces · Jun 10, 2019

The real Leigh said:
As Ted mentioned, they're taper pin reamers.

They're used to open up drilled holes to fit taper pins.
You drill a hole slightly smaller than the small end of the pin, then ream it to size.

The reamers and the pins are still readily available.

Those are very popular for attaching items like handles to shafts.
Monarch used them all over the place on their lathes.
They're very reliable, staying securely in place for many decades if seated with a gentle tap.

- Leigh

I'd rather drill the hole the same size or slightly bigger than the bottom dia of the reamer but that's because I'm lazy.

Regards Tyrone.

steve-l · Jun 10, 2019

The use of taper pins is an art form. It is very easy to mess things up. There are numerous threads in the archive on what to do and what not to do.

Tyrone Shoelaces · Jun 10, 2019

steve-l said:
The use of taper pins is an art form. It is very easy to mess things up. There are numerous threads in the archive on what to do and what not to do.

Thanks for that Steve, I've never considered myself an artist before today.

Regards Tyrone.

DMF_TomB · Jun 10, 2019

taper pin reamers especially smaller ones tend to break easy. thus why many have alot of them some dull and some new all different sizes.
.
when hand reaming i prefer a air drill as they are usually smaller, lighter, and lower torque than many electric drills
.
you can get taper pins where end has either a external thread or a internal tapped hole to assist in pulling or removing you use extra washers and a nut or screw to pull taper pin. if its a thru hole you can tap with a punch and hammer the small side of the pin.
.
sometimes dowel pin holes loosen up over many years if too small and load is high. a taper pin if slightly loose you just tap it into tap further to tighten and or ream for next bigger size pin

L Vanice · Jun 10, 2019

I have three types of taper pin reamers.

1. Hand, with square ends for a tap wrench and straight flutes, stored in an oak block that I made.

2. Machine, with round shanks and left hand spiral, right hand cutting flutes, stored in a steel drill stand and a smaller set in a cool aluminum stand that I bought somewhere.

3. Machine self-drilling reamers made by Capital in England stored in a black plastic drill stand. Note that these have a right hand spiral and chip breakers, and the ends are ground like a drill bit.

All of them have the standard US pin size on the shank, from around 7/0 to 10.

I have a good supply of pins, but can't recall the last time I used one. I started using them around 1964 and occasionally for another 25 years or so. They are just the thing for some jobs, and I find them in some of my old equipment.

By the way, I do have a bunch of tapered end mills, bought when the local GE die shop auctioned off. They are used for making dies with specific draft angles on the walls. I tried to use one for reaming a tapered hole once and it made a mess, leaving chatter marks in the hole. All of my tapered end mills are marked with the side angle in degrees.

Larry

Tyrone Shoelaces · Jun 11, 2019

If we're talking about fitting taper pins please don't do what I've seen done before and file and emery polish both ends of the fitted pin so they can't be seen ! It looks very nice and neat but 5 years later when somebody wants to remove the pin - where is it ?

The convention when I was an apprentice was that you left both ends of the pin roughly 1/8" proud and you stamped the collar or whatever it was that was being pinned H and D on either side of the head of the pin so the head end could easily be identified.

Regards Tyrone.

crossthread · Jun 11, 2019

I hear you Tyrone. I had to knock a tapered pin out of a bull gear on one of my lathes and could not figure out which way to whack it. Took me a while to figure that one out. Thanks.

What are these tapered end mills used for?

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