Reamer Education Needed

[Kroll]

Good morning guys,well I need a little education on reamers.Which ones do I need,how to use them,hand or chuck,straight or spiral,etc.Guys my background when it comes to reamers is null,I have never use one before or even heard about them until I came across this site.I always though that a hole made by a drill bit was round until I read a posting that they are not so a reamer is needed.Guys if possible start at the beginning cause I know nothing about them.
Why now do you ask about Reamers??? Well I have a hole to repair which you can read here. about http://www.hobby-machinist.com/threads/sb-fourteen-hit-a-snag.53549/
Guys I went to ebay and started looking first for a set,then individual reamer and the brands and prices are all over.I really don't know what I need,while I would like a set but I can't say how often I would use them.Just a hobby type person just playing around,but want my reaming to be spot on and the best it can be.If you have a set that's in the middle of the road or individual reamers please let me know either with a link and where you purchase yours or link to ebay would also be nice.Thanks guys for any directions both learning how to's and what to buy----kroll

 

[Chuck K]

I really don't know what I need,while I would like a set but I can't say how often I would use them

Before I got comfortable with boring bars on the lathe and boring heads on the mill, I thought that every hole I made had to be drilled and reamed. First...remember that a reamer will follow an existing hole. If it's a drilled hole, it might not be straight to begin with. If it's a properly bored hole you might not need to ream it. If I had to do it all over again, I would buy good quality expandable hand reamers in a couple of sizes and get the spiral and straight reamers for the mill and lathe as I needed them. The thing about reamers is that I don't use them that often but when I need one it's just about the only thing that will work for the project. The other thing is that if you're patient you can collect a lot of them for almost nothing. You could do the project on the SB 14 without a reamer but then you would pass up the chance to add to your tool collection. (I wanted to add a smiley face here but I'm emoji challenged)

 

[schor]

Buy them as you need them. You only need to ream the hole if you want high accuracy on the bore.

I got all my reamers in tool scores, only ever used them a few times.

 

[Whyemier]

My knowledge and experience is limited on reamers. I have found if I want a the diameter of a hole close to size a reamer is the way to go if I can't bore the hole or if the set up to do so is more involved than I want to mess with. I don't ream unless the diameter is critical and a drilled hole will do for most of my applications.
I picked up the reamers I have as I have gone along. Some came with my original tool box and tool purchase. Others I've picked up on E-Bay as I've gone along.
Just my thoughts. Don't listen to me.

 

[Wreck™Wreck]

HSS chucking reamers as used in a machine are easily sourced in fractional, letter, number, wire gauge, dowel pin and decimal sizes with straight flutes. These are general purpose tools.

Spiral flute reamers are excellent for holes that have already been cross drilled or have other features that straight flutes will run afoul of. They often produce a better surface finish as well.

A reamer is not intended for correcting misplaced holes only for making a round accurate sized hole when used after a drill or other process such as punching.

This is an example of available chucking reamers, McM is rather expensive but they do stock everything for same day shipment. https://www.mcmaster.com/#chucking-reamers/=15mfofd

 

[brino]

Great thread! Thanks @Kroll and everyone.

In one of his book Dave Gingery mentions it's really the over/under sized reamers that get the most use.
Undersize for press fits.
Oversize for clearance fits.

How much over/under depends on what your doing and the materials being used.

-brino

 

[4GSR]

kroll,

I have several duplicates in the smaller sizes up to 1/2". If you like a few to play with, PM me your shipping address and I'll select a few and send them to you. Won't cost you a thing!

Ken

 

[Tony Wells]

If you have to buy one for a particular job, get a LH spiral, RH cut. In addition to what Wreck said, they also will produce a rounder hole with a better finish when used in a machine than a straight fluted reamer.

 

[GLCarlson]

Notes above cover most critical points.

There is one old machinist's trick I don't see discussed: cutting fluid. Everyone will agree one is needed, and the common choices are chlorosulfonated pipe threading oil, or -for aluminum- Relton A9 or the many inferior recent entries.

NONE of those is the best choice. Get thee to the cooking aisle at the food store and grab a small can of Crisco. Load the flutes of the reamer full, end to end and right up to the top. If you've drilled your hole correctly, a few thou undersize, you will be delighted by how smoothly the reaming goes. A full load of vegetable shortening floats the reamer into the hole, and seems to have just the right amount of lubricity and thickness to ensure a good job. Just wipe it out of the flutes when you're done. This has worked with everything; aluminum, steels from A36 to 8620, cast iron, brass, bronze, whatever.

This works great for hand reaming, or one-off jobs in the lathe or mill. If you're machine reaming multiple holes with a rigid setup in the mill, it's way too tedious and the Crisco needs frequent replacement. Not recommended there, but in that case regular coolant will work fine.

I heard this one many decades ago, and still have that can of Crisco.

Final thoughts. Never turn a reamer backward, even when removing. Always and ever, rotate in the cutting direction, no matter which way you're moving in the hole.

I second the idea of buying good quality in the size you need now. A set of cheap reamers is no bargain, you mostly won't use them. Buy as needed, in the size needed. In 30 years, you'll have a full set....

 

[4GSR]

Good old Crisco. I learned that from an old timer back when I was about 17 years old. Used his shop to drill and tap a hole in a sprocket for my granddad's oilfield cementing truck.. Ask him if he had any cutting oil to help with the dull tap he had, he handed me a can of Crisco. No Tap Magic in his shop! It worked! In fact, when I got home, I bought a can and used it for years until it got a little crudded up and I tossed it out when we moved the lathe.