Just curious about tapered drills

[Bi11Hudson]

Is it possible It is possible that what I thought was a tapered drill is is truth a tapered spiral reamer that was sharpened on the tip. Further, the tapered drill I am searching for is actually a drill at the tip and a reamer up the length. Both are plausable to me, but I'm not a machinist. A morse size drill would be a matter of "convenience".

As I stated in the original post, the accepted shop practice is to drill the small size and then drill larger at reduced depth. I have a copy of Machinery's Handbook from around 1940 that recommends such a procedure. It may well be that this is the reason that some older machines have the taper at each end but do not grip in the middle. I do not anticipate making a Morse Taper in a squared off block. But was thinking of possibly repairing/making a quill for a drill press. I do have a fitting for a QC Tool Post that is Morse, but I don't use it. Nor do I anticipate ever needing to. It came with the set when I bought it. It may well be knowledge of that piece that biased my thoughts on the subject.

As far as pipe sizes, I am "studying" on a problem I am having with my (domestic) hot water tank. The temperature relief valve is leaking around the threads. I am blaming the government here, brass has been only marginally usable since leaded brass was outlawed. There is a small groove up the side of the tank fitting where the leak is occuring.

I am thinking about using a pipe tap to cut the threads a fuzz deeper. Combining the deeper threads with an extra layer of teflon may well stop the leak. There is a dielectric insulator between the tank and the fitting. I'll need to go easy on the tap, maybe a half turn at most. But the leak is seepage, not a spurt. If it works, it'll be a few hundred $ cheaper than a new tank. It has only been in use around ten(10) years. The one it replaced was in the house when I bought it and served me for 30 years. Who knows how old it actually was. It was still holding pressure, I converted from gas to electric. Ces't la vie, but it got me to thinking along those lines.

.

 

[mmcmdl]

s it possible It is possible that what I thought was a tapered drill is is truth a tapered spiral reamer that was sharpened on the tip. Further, the tapered drill I am searching for is actually a drill at the tip and a reamer up the length. Both are plausable to me, but I'm not a machinist. A morse size drill would be a matter of "convenience".

Bill . If you are speaking of a dreamer , yes they exist . Not sure if I've ever seen them tapered though .

 

[Jimsehr]

Amazon Zoro ,and MSC has them I googled tapered pipe reamers and found them for pipe threads but not for Morse tapers.

About 40 years ago I reamed some Morse tapers and if I remember correctly I used the lathe compound to rough in the taper with a bore bar.

 

[mmcmdl]

Yes . Hard to say just what Bill is looking for . Bill , can you clarify ?

 

[Parlo]

About 40 years ago I reamed some Morse tapers and if I remember correctly I used the lathe compound to rough in the taper with a bore bar.

That's what I was thinking, Morse tapers are generally inside a round bar, so could be machined on a lathe. The post earlier did answer my question, morse tapers can be found in lathe toolholders.

 

[Parlo]

I am thinking about using a pipe tap to cut the threads a fuzz deeper. Combining the deeper threads with an extra layer of teflon may well stop the leak. There is a dielectric insulator between the tank and the fitting. I'll need to go easy on the tap, maybe a half turn at most. But the leak is seepage, not a spurt. If it works, it'll be a few hundred $ cheaper than a new tank. It has only been in use around ten(10) years. The one it replaced was in the house when I bought it and served me for 30 years. Who knows how old it actually was. It was still holding pressure, I converted from gas to electric. Ces't la vie, but it got me to thinking along those lines.

.

Please don't rely on Teflon to make a seal. The idea of Teflon and other friction limiting pastes / tapes is to reduce galling and allow higher tightening torque to make a tighter mechanical seal.

 

[dbb-the-bruce]

A Correction, McMaster is where I got my taper pin drill-reamer they come in size from tiny to huge (9" long!)
Only two tapers, metric and english (1/4" per 12")

 

[Janderso]

A Correction, McMaster is where I got my taper pin drill-reamer they come in size from tiny to huge (9" long!)
Only two tapers, metric and english (1/4" per 12")

I always step drill my tapered holes. I didn’t know they made such a thing.

 

[Bi11Hudson]

It seems that at one time, tower erectors sometimes used a tapered rivet. I was told only that it was an archaic practice and not used these days. That would account for the mentioned "dreamers". I have Morse reamers both roughing and finish in the sizes I work with.

The original thought came about from prepping for pipe fittings. The concept of Morse Taper drills was an extension of that from a curious mind. I was thinking of a production environment where saving the steps and/or tool wear of predilling or "brute force" reaming of Morse holes would pay for acquisition of a tapered drill.

Beyond the pipe prepping, think of it as an acedemic exercise.

.

 

[dbb-the-bruce]

Thanks for the academic exercise.
Since you mentioned it, I'll add another one that this whole thread got me thinking about.

At what point does a drill become a reamer?

A typical drill has a point angle of 118 or 135 degrees. As that point angle gets bigger and bigger 150, 200, 300 340 degrees say, when does it become a reamer? Obviously, a point angle of 360 (parallel sides, a straight reamer) has no point.

Is a tapered reamer with a 1 to 1 ratio a drill with a 270 deg tip? or is it just a chamfer bit?
If you put chip breakers on the flutes of a spiral taper reamer does it become a drill?

The only hard definition I could come up with is that a reamer is used to fine tune an existing hole.

Clearly the cutting edge(s) of a reamer are MUCH longer than the cutting (lips) of a drill bit. The longer the cutting edges the bigger cutting force will be for the same depth of cut. Hence reamers are used to remove small amounts of material. It's not efficient to ream a small hole to a much bigger diameter, and there is also the problem of removing chips. An extremely pointy drill bit is much more prone to break.

Drills are for removing material, reamers are of refining a hole. If you have a slow enough taper or a short enough hole, you can do both at once.

IDK - just some mind wandering. Hope it amuses people