First time reaming question

[dml66]

I have a 0.250" diameter chucking reamer ordered, am hoping for suggestions on which machine to run it in; lathe or drill press.

The reamer looks like the one below, straight flutes:


The existing hole is about 0.3" deep, it is a through-hole.

Regardless of which machine I use, the workpiece and the reamer can swap positions: In the lathe, I can chuck the reamer, or the workpiece, same for the drill press.

From what I've read, reamers want to "follow the hole", also that it's best to let the reamer go fully through the hole, stop the machine, and retract the reamer.

The advantage to running this on the lathe is I have full, independent control over feed rate, if that turns out to be important for hole finish. My concern with the lathe is that the reamer, because it's horizontal, will also want to "follow gravity" both in the hole, and once it pushes all the way through.

On the other hand, the drill press offers no way to control feed rate; either I can do that manually, or release the quill spring enough so gravity does it.

In any event, I'm hoping for some guidance so I don't start out doing it as wrong as possible, an approach I sadly excel at

 

[francist]

I would run it in the lathe for the simple reason you can likely go dead slow. I’ve never used any of my reamers in the drill press, gravity be damned!

 

[mmcmdl]

Either , or . Really no difference other than preference . If your part is mounted in lathe , use the lathe . If removed , use the drill press . My personal preference when having the choice would be a mill or drill press where hand feeding is achievable . The lathe tailstock has no " feel " . Reamers don't and can't back cut while removing from hole , no need to turn spindle off . Reamers are tapered .0005 per inch so only the front lead is doing any work .

 

[Jake M]

Reamers are quite simple things, but they're a little bit persnickety. It's not like a drill bit even though it kind of is.... But before I scare you off.... It's not that bad either. They feed a little slower than you'd think (But KEEP THEM FEEDING, don't let them dwell. A drill press with a hand operated quill, a tailstock chuck with a screw operated feed, powerfeed if you could figure out how to arrange that... All will work fine.

Whatever speed you have the best success drilling the hole at, you're going to want to be at half of that or less. Not the speed chart speed for that sized drill, but half of the actual speed where you have good success. Which it's self is (probably) well less than the published "speed limit". Half or a little less of YOUR most successful speed.

Of course, that speed will (probably) depend what machine you're using.....

Do NOT stop the reamer to back it out. Run it in and out while it's rotating. Lots of oil (or whatever cutting lubricant you're using), modest speeds, modest feed pressure/feed rate, and you're not describing a very deep hole... Conservative speeds, conservative speeds, constant CONFIDENT smooth motions on all the above, like you just know it's gonna be fine.... You'll be fine. These are one of those tools that can smell fear. Hesitation, "too slow" of a feed, and generally being "too careful" can make them act up just as much as heavy handeness can.. Don't hesitate, don't stop, just keep it moving confidently at those modest speeds and feeds, get it in and then get it out out, you'll be fine.

As far as the setup, it really doesn't make much difference which one you spin, whatever way it's easiest to set up would arguably be the best way. I would suggest that drilling the hole and then reaming it in the same setup would be the best orientation, whichever way you chose to accomplish that would be fine. If that setup is lost already, I wouldn't loose any sleep, but the more concentricity you can maintain, the more on size that hole is going to come out. Even if you're not perfect in your technique, the hole is gonna be pretty darned accurate. Even a "badly" reamed hole is still WAY more accurately sized and better finished than a drilled hole.

 

[durableoreo]

I've heard drill 1/64th under the reamer size. The lore is that cutting with oil results in a slightly smaller hole. Here's a series on the basics:

 

[RaisedByWolves]

I've heard drill 1/64th under the reamer size. The lore is that cutting with oil results in a slightly smaller hole. Here's a series on the basics:

1/64th is a good rule of thumb, but as the size of the hole goes up this can be taken to 1/32 or even more depending on hole size.

Stopping the reamer is good practice as it keeps it from marring up the nice hole you just made.

You literally want as much cutting oil on the reamer as practical. I use an acid brush and keep oil flowing down the flutes while cutting by dipping it and reapplying every couple seconds.

As to oil and hole size, you’re reamer should cut on size, if not your doing something wrong, see below.

Not sure I can think of a reason to use a reamer dry, but I can think of lots of problems this could cause, chip welding causing it to cut too big or inaccurately being one.

 

[SouthernChap]

1/64th is a good rule of thumb, but as the size of the hole goes up this can be taken to 1/32 or even more depending on hole size.

Stopping the reamer is good practice as it keeps it from marring up the nice hole you just made.

You literally want as much cutting oil on the reamer as practical. I use an acid brush and keep oil flowing down the flutes while cutting by dipping it and reapplying every couple seconds.

As to oil and hole size, you’re reamer should cut on size, if not your doing something wrong, see below.

Not sure I can think of a reason to use a reamer dry, but I can think of lots of problems this could cause, chip welding causing it to cut too big or inaccurately being one.

You know, I hear people mentioning undersized and oversized reamers for imperial and I've seen them for sale.

Do you (or anybody else) know why this isn't a thing in metric?

Or rather, I've never seen them available and not heard anybody mention such a thing. If they are available can anybody point me in the right direction? I don't need this facility right now of course but might be nice to know where to get them if they were to exist.

 

[verbotenwhisky]

I have a 0.250" diameter chucking reamer ordered, am hoping for suggestions on which machine to run it in; lathe or drill press.

The reamer looks like the one below, straight flutes:

View attachment 470147
The existing hole is about 0.3" deep, it is a through-hole.

Regardless of which machine I use, the workpiece and the reamer can swap positions: In the lathe, I can chuck the reamer, or the workpiece, same for the drill press.

From what I've read, reamers want to "follow the hole", also that it's best to let the reamer go fully through the hole, stop the machine, and retract the reamer.

The advantage to running this on the lathe is I have full, independent control over feed rate, if that turns out to be important for hole finish. My concern with the lathe is that the reamer, because it's horizontal, will also want to "follow gravity" both in the hole, and once it pushes all the way through.

On the other hand, the drill press offers no way to control feed rate; either I can do that manually, or release the quill spring enough so gravity does it.

In any event, I'm hoping for some guidance so I don't start out doing it as wrong as possible, an approach I sadly excel at

I would think Lathe, less chance of issues with run out unless you have a really great chuck in the drill press.

 

[RaisedByWolves]

You know, I hear people mentioning undersized and oversized reamers for imperial and I've seen them for sale.

Do you (or anybody else) know why this isn't a thing in metric?

Or rather, I've never seen them available and not heard anybody mention such a thing. If they are available can anybody point me in the right direction? I don't need this facility right now of course but might be nice to know where to get them if they were to exist.

That's because nobody uses the metric system anymore.

I would think Lathe, less chance of issues with run out unless you have a really great chuck in the drill press.

The problem with using a reamer in the lathe is the tailstock can be off in any direction making the reamer ream a cone, the chuck only adds to this problem.

This is why there are boring bars.

 

[WobblyHand]

You know, I hear people mentioning undersized and oversized reamers for imperial and I've seen them for sale.

Do you (or anybody else) know why this isn't a thing in metric?

Or rather, I've never seen them available and not heard anybody mention such a thing. If they are available can anybody point me in the right direction? I don't need this facility right now of course but might be nice to know where to get them if they were to exist.

Over and undersized reamers are typically +0.001" and -0.001" around nominal size, or roughly +0.0254mm and -0.0254mm. Haven't seen any metric reamers offered at that spacing. Think I found some reamers at 0.05mm offset, but not less. Interesting that they are not common in metric. I've seen 0.0005" increments on imperial reamers.