Could I get help picking a set of reamers?

[FKreider]

Interesting results Steve, looks plenty accurate for a live steam locomotive!

[NP317]

Interesting statistical look at reaming results.
Thanks for sharing your considerable research efforts.
RussN

[hoppercar]

If your going to ream, you need to be sure the hole is running good after drilling, before reaming...as a reamer will only follow a drilled holes path.....so with that in mind....why ream at all..just bore to size

[Harold_V]

as a reamer will only follow a drilled holes path

While I agree fully that boring is the real solution, I don't necessarily agree with your assessment of a reamer following a drill's path. Keep in mind, I am NOT a fan of reamers, although they do have their place. They are well known for creating holes that are not round, and can also suffer from bell-mouth.

In regards to a reamer correcting a wandering hole, a great deal depends on the amount of stock remaining to be removed, and the nature of the error of the drilled hole. It's not uncommon for a reamer to straighten a crooked hole, leaving witness marks where the drill had wandered, with the reamer averaging the condition by removing the *highs*. Any surface beyond that plane has no material to remove, thus the witness marks.

Both hand and chucking reamers have the ability to change alignment on a drilled hole. The hand reamer can because it cuts on the flutes, and will always take the highs off, while a chucking reamers (in theory) cuts only on the end. That may not alter alignment, however, so if a hole leans, the reamer is likely to follow the lean angle.

With a chucking reamer, the circular ground lands are intended to behave as guides, so the reamer cuts a straight line. That said, assuming the beginning of the chucking reamer's hole is not deflected, the reamer will straighten a wandering drilled hole. It may not be totally corrected, but it will be improved.

Nothing beats boring where a round and straight hole, on location, is desired. It can then be improved, if necessary (made truly round and finish improved), with a rigid hone if required.

H

[hoppercar]

Guess it all depends on how bad the drill wobbles.....I have seen guys still a hole without a centerdtill and causing the drill to wobble, and the reamer just follows it...and on the other hand, I've seen carefully drilled holes....and the reamer dies just fine....after 40 years in a tool room....I guess I seen a lot..lol lol.....but your right, reamers do have a tendency to bell mouth.....so for the beginner, I would recommend just boring.....my 2 cents...lol.lol....thanks for your input

[10 Wheeler Rob]

I found a set of the 1/8" to 1/2" over and under reamers to be very helpful in making a lot of parts. I agree they are not ideal for wheel bores.

I also found low cost set of the the blade type adjustable hank reamers to be useful for fine tuning and getting a nice bore finish on some items.

[ALCOSTEAM]

If you want to have something to do small hole size checks with, get a set of tapered lathe arbors. Put a mark on the arbor and then bore till the small end just starts into the hole. Then just a .001 or so and usually you are mid arbor. I have bored parts most of the day and have been using a tapered arbor as my check gauge. Every hole is within 1/4" of my mark on the tapered arbor and the arbors are .0005 per inch taper and I can live with that.
Also don't rely on your lathe dials to be perfect. If you need .0005 its way easier to watch a dial indicator than to guess that on a lathe dial. Get a dial indicator and attach it so that you can SEE your cross slide movement on the dial indicator.
Over the years I have bought a few reamers new, virtually all to be used on the mill over a previously bored small hole that needs to be exact on size.

[Greg_Lewis]

...
I also found low cost set of the the blade type adjustable hank reamers to be useful for fine tuning and getting a nice bore finish on some items.

Be careful. There is low cost and there is cheap. Many decades ago I bought a set from a supplier (no longer in business) whose prices were way below anyone else. There was a reason for that.....

[Harold_V]

Guess it all depends on how bad the drill wobbles.....I have seen guys still a hole without a centerdtill and causing the drill to wobble, and the reamer just follows it...

With that I agree. What you're talking about is location, and a reamer doesn't generally have the ability to make a correction for that feature.
What I was talking about is drill wander in a deep hole, where it tends to meander. Once started, it will follow the path it generates, even if it isn't perpendicular to the drilled hole at the opposite end. In that case, it's not unusual for the reamer to end up yielding an ellipse, with the area that has wandered beyond the centerline of the reamer not having any material to ream.

and on the other hand, I've seen carefully drilled holes....and the reamer dies just fine....after 40 years in a tool room....

Yep! I've seen that, too, but I'd qualify the results as acceptable. I don't have your years in the toolroom, but I did work as a machinist/toolmaker for 26 years, the last 16 of them self employed. I also spent more than five years in precision grinding, where I learned the real problem with reamers, and their general inability to produce straight (read that tapered, not bent) and round holes, let alone their ability to yield various diameters, generally due to variations of feed rate and irregular lubrication. You want a good hole? Bore it. Want to improve it? Hone it. The best reamer won't come close to the ability of a rigid hone, but then that level of quality is most likely not required in most cases.

I used reamers for years, primarily for dowel pins in tools. For that they were unbeatable, and the slight irregularities were not features that were inspected or specified. They performed their intended duty, and that was what was important. Pretty hard to work with dowel pins without them.

H

[shild]

Thanks for the replies everyone! For what is probably the most important reamer to do the wheels, I got a 5/16 Morse. This pic is of the tools I plan to use from top to bottom to do each wheel. First I indicte in the 4-jaw, then face off, then center drill, then 19/64 drill, then 5/16 ream. Is this how I want to do that wheel? Should I be using a larger center drill? Drivers call for a 7/16 reamer and I think I'll try to bore that.

[AnthonyDuarte]

Sounds like a lot of of extra steps. Just drill it 3/8” and finish with the boring bar. If you’re concerned about holding size on each wheel with a boring bar, you could get it close with the boring bar and finish with a 7/16” reamer. That way you at least know you’re reaming a straight hole.

[NP317]

For those wheels (I have machined those exact same castings) I adjusted them in the 4-jaw so that the inside of the outer rim ran true.
All other surfaces will be machined anyway. This results in wheels win no visible "radial wobble."
It's an obsessive-compulsive thing with me...
RussN