Reamers

[rwm]

I have a specific question but I think there are a lot of knowledge gaps about reamers. Maybe other questions will get answered here.
Firstly, why does this reamer appear to NOT have a "lead in." It has a square edge like and end mill. How would this center? Is this really a reamer?




Secondly, I know spiral flute reamers are good for holes with cuts or keyways. Why are all reamers not spiral flute? Why straight flute?
Thirdly, why do "hand reamers" often have an MT shank? That would appear to mean they are meant for machining.

 

[Jim F]

It is a counterbore, missing the pilot.

 

[ChazzC]

It is a counterbore, missing the pilot.

I knew something didn’t look right (it’s definitely end-cutting, and the spiral flutes didn’t look like a spiral reamer), but hadn’t had a chance to go look at my tooling. I have piloted counterbores, but use them infrequently.

 

[woodchucker]

hand reamers do not have MT tapers. They have square ends like a tap.. Hand reamers have a lead in, chucking do not, they have a very slight chamfer.

Glad Jim chimed in, because it didn't look like a reamer, but I wasn't sure.

 

[rwm]

Counterbore makes more sense!
The “hand reamers“ I am looking at have an MT taper and a square end.

LOT OF 3 CLEVELAND HSS HAND REAMERS 3/4" 1" & 1-1/2" DIA | eBay

3/4" Dia x 4-1/4" Cut Length. 1" Dia x 5-1/2" Cut Lengths. 1-1/2" Dia x 6-1/4" Cut Length.

www.ebay.com

 

[ChazzC]

Counterbore makes more sense!
The “hand reamers“ I am looking at have an MT taper and a square end.

LOT OF 3 CLEVELAND HSS HAND REAMERS 3/4" 1" & 1-1/2" DIA | eBay

3/4" Dia x 4-1/4" Cut Length. 1" Dia x 5-1/2" Cut Lengths. 1-1/2" Dia x 6-1/4" Cut Length.

www.ebay.com

I think they are straight shank (taper is an illusion); MT reamers have a tang.

 

[rwm]

Could be.

 

[woodchucker]

Counterbore makes more sense!
The “hand reamers“ I am looking at have an MT taper and a square end.

LOT OF 3 CLEVELAND HSS HAND REAMERS 3/4" 1" & 1-1/2" DIA | eBay

3/4" Dia x 4-1/4" Cut Length. 1" Dia x 5-1/2" Cut Lengths. 1-1/2" Dia x 6-1/4" Cut Length.

www.ebay.com

they look like straight shanks... does it say MT somewhere?

 

[extropic]

It's not a reamer (or a counterbore). It is looks like a Jig Bore Style Reamer. I don't know why they have that name. The characteristics I pay attention to are relatively long reduced diameter straight shanks and otherwise, at a glance, they look like end mills. A quick browser search didn't yield any new sources, only used.
I don't know why they have that name or what special characteristics they have to justify that name. I would use it as an end mill, with appropriate consideration for it's proportions. See reply #21.

For example:

Weldon JIG BORER REAMER Set of 8; HSS high speed steel bore w/ Moore Tools Tray | eBay

Weldon JIG BORER REAMER Set of 8; HSS high speed steel bore w/ Moore Tools Tray. Sizes: 1) 1.1253" x 1/2" shank; 1) 1" x 1/2" shank; 2) 13/16" x 1/2" shank; 2) 13/32" x 1/2" shank; 2) 3/16" x 3/8" shank. Used, very good condition.

www.ebay.com

 

[extropic]

I looked a little harder.

Jig Bore Style Reamers | Alvord-Polk