Hole Sizes for Reaming

[EdK]

I need to ream some 1/2" and 3/8" holes in some 12L14 and was wondering if 1/64" undersize is the correct size for reaming? I haven't done a lot of reaming so I'm deficient in reaming knowledge.

Thanks,
Ed

[doubleboost]

(05-05-2013, 02:12 PM)EdK Wrote: I need to ream some 1/2" and 3/8" holes in some 12L14 and was wondering if 1/64" undersize is the correct size for reaming? I haven't done a lot of reaming so I'm deficient in reaming knowledge.

Thanks,
Ed

Hi
Ed
That should be fine
I use 0.2 mm undersize
Never turn the reamer in the wrong direction (but you will already know that)
John

[EdK]

(05-05-2013, 02:59 PM)doubleboost Wrote:

(05-05-2013, 02:12 PM)EdK Wrote: I need to ream some 1/2" and 3/8" holes in some 12L14 and was wondering if 1/64" undersize is the correct size for reaming? I haven't done a lot of reaming so I'm deficient in reaming knowledge.

Thanks,
Ed

Hi
Ed
That should be fine
I use 0.2 mm undersize
Never turn the reamer in the wrong direction (but you will already know that)
John

Thanks John. I'll soon see how it goes.

Oh, what RPMs should I be using for 1/2" and 3/8" reamers?

Ed

[doubleboost]

(05-05-2013, 03:10 PM)EdK Wrote:

(05-05-2013, 02:59 PM)doubleboost Wrote:

(05-05-2013, 02:12 PM)EdK Wrote: I need to ream some 1/2" and 3/8" holes in some 12L14 and was wondering if 1/64" undersize is the correct size for reaming? I haven't done a lot of reaming so I'm deficient in reaming knowledge.

Thanks,
Ed

Hi
Ed
That should be fine
I use 0.2 mm undersize
Never turn the reamer in the wrong direction (but you will already know that)
John

Thanks John. I'll soon see how it goes.

Oh, what RPMs should I be using for 1/2" and 3/8" reamers?

Ed

Very slow with cutting fluid
John

[wrustle]

(05-05-2013, 03:10 PM)EdK Wrote:

(05-05-2013, 02:59 PM)doubleboost Wrote:

(05-05-2013, 02:12 PM)EdK Wrote: I need to ream some 1/2" and 3/8" holes in some 12L14 and was wondering if 1/64" undersize is the correct size for reaming? I haven't done a lot of reaming so I'm deficient in reaming knowledge.

Thanks,
Ed

Hi
Ed
That should be fine
I use 0.2 mm undersize
Never turn the reamer in the wrong direction (but you will already know that)
John

Thanks John. I'll soon see how it goes.

Oh, what RPMs should I be using for 1/2" and 3/8" reamers?

Ed

Ed, a VERY simple rule of thumb for reaming feeds and speeds is to halve the speed and double the feed for what you would drill the material at based on the SFM of the material you are working with.

Example: .500" Dia. reamed in 12L14

.484" drill = 710 RPM 6.2 IPM

.500" Reamer = 355 RPM 12.4 IPM

Always works for me, no reason it should not for you!

Best Regards,
Russ

[f350ca]

All of the above but if you sharpen your drill bits by hand make sure they aren't cutting oversize. 1/64 is perfect for reaming but 1/64 over size if the bit faces aren't even isn't impossible.

[EdK]

(05-05-2013, 07:09 PM)f350ca Wrote: All of the above but if you sharpen your drill bits by hand make sure they aren't cutting oversize. 1/64 is perfect for reaming but 1/64 over size if the bit faces aren't even isn't impossible.

Thanks Greg. I have a Drill Doctor that works well for me so no hand sharpening of drill bits. Some say the Drill Doctor is a piece of crap but I've found it to work very well and probably a whole lot better than if I was to try sharpening by hand.

Ed

[f350ca]

I picked up one on sale a while ago too. I still sharpen mostly by hand, especially the larger bits, it does a good job but I find my hand ground ones cut faster, I must grind more clearance or something.

[Highpower]

Even with a Drill Doctor (I have one too) you can still end up grinding more off of one flute than the other. Most of us don't have eagle eye vision anymore and still need measure the length of the cutting lips to make sure they are equal, otherwise it's going to drill an over-sized hole.

[f350ca]

With my eagle eyes I have trouble reading the drill guage.