drill doctor

Drill bore, ream will give a more accurate hole. not perhaps rounder, but more in the correct place. Ream for exact size, easier than boring to that size.
 
T Bredehoft said:
Drill bore, ream will give a more accurate hole. not perhaps rounder, but more in the correct place. Ream for exact size, easier than boring to that size.
Click to expand...

I have had both good and bad luck with reamers. Sometimes they come out oversized, using a correct size, not an over, or under reamer. If I am worried and don't want to bore, I'll ream under and lap to size. As far as it being concentric, I think boring is the best choice.
My opinion, yours may differ.. that's ok too.
 
I have a 750 and it works well for many bits but there are some bits that just defy sharpening in the thing. I think it is due to the flutes not being a standard twist.
 
Wreck™Wreck said:
Just a question, if you set up a machine for a boring operation why would you use a reamer afterwards? Would not drill and ream be more expedient.
Click to expand...

I could be wrong, but when I was in school we were taught drill, bore, ream if you want accurate hole. If your drill takes a turn east or west while drilling, the reamer will follow it. A sharp boring tool will more likely straighten the hole out, then ream to final size.
 
I have a tradesman 500, the older tall green one. I've had it too long to remember. It does a great job on drills up to 1/2". Above that I sharpen by hand on a bench grinder. As with any machine you need to develop a feel for it and this takes a little bit of time. Follow the instructions provided with it and then practice with a few drills. It is worth the price if you are old and have problems with your eyes and maybe not a steady hand. It is a good idea to get one or two extra diamond wheels. Also it is a good idea to get a drill angle gauge to check for equal length on the cutting lips. I also have the left hand chuck for it. Just don't have the 3/4" chuck and it is no longer made.

Roy
 
Last edited:
Drill grinding machines and aids, all of them, work but are not foolproof. Same with doing it by hand and eye. You have to know what you are looking for in the finish grind, and know how to get there. At a bare minimum, read the instructions, beyond that some study of drill geometry and how drills work is necessary. Then you have to understand how to adjust the geometry to get the desired results. All quite doable, but just being in the dark and making sparks will not get good and consistent results -- with any method. I have a DD750, an old Craftsman swing jig that mounts next to a bench grinder, and my eyes and a grinder rest. I get excellent results using any of those methods. The DD is the least fussy of them.
 
Well, I guess I’m alone on this one. I have used a DD and was not impressed. Cheap construction for one. Hard to control equal land grinds on the bit for two. I can keep going… I sharpen by hand even small ones like #80 using a loupe and abrasive disc. I have a Darex, does OK, a little better construction but not totally the best. I have it set-up for 135° split point…Dave
 
Last edited:
I have a DD 750 as well and have found it very useful in keeping bits sharp.
If I have a bit that is really bad I either hand grind to close (as I am not a great free hander) or toss it.
 
Have both, good results. I like sharp bits.

A very economical solution.
 
You must log in or register to reply here.
Back
Top