Need of some "old school" knowledge! - Sharpening bits

[11echo]

I'm a hobbyist machinist! I've been doing this afew years now. Normally I pick up older machines, rebuild them to the best of my ability and try to use them to their extend. Same goes for cutting tools ...ie drill bits. I get old drill bits (usually with a #2 or #3 MT shank) clean them up and try to sharpen them ...per my high school shop training (or what I remember of it). Seem to be semi successful on larger bits (over 3/4" dia.). But I have trouble with the smaller ones (especially below 1/2"dia.) ...primarily because I don't think I know how to deal with the smaller bits. SO can anybody point me to where I could get some info on how to hand grind these and reamer too (I just picked up a number of them too)?
YES I've tried "googling" ...but most of what I'm finding is "Drill Doctor" type machines. I'm looking for old school hand grinding techniques!! THX! ...Mark

[Glenn]

IForgeIron > Blueprints > BP0223 Sharpening Drill Bits

[markb]

I've used these wheels in the med. and finer grits on small bits with the above posted technique

Cratex - Rubberized Abrasives Catalog - Large Straight Wheels

[agsolder]

Lindsay Books-- www.lindsaybks.com-- has many old time machinist texts in their catalog, including some specifically re: drill bits. Their print catalog has much more than the on-line list of goodies.

[R Funk]

I hand grind my drill bits, but do not know how to explain how to do it over the computer....

One of the most important items, outside of patience, precision and good lighting, is a simaltaneous rolling and changing the angle of the drill bit. This step is critical to get the clearance but comes only with practice.

As far as grinding a reamer I know of no way to hand grind a reamer. This is a certain path to ruining a reamer in my opinion.

With a small abrasive stone, for example a 1/4" X 1/4" X 6", you could "stone" the radial face of the cutting edge to get a fresh edge. DO NOT TOUCH the outside diameter of the reamer with the stone. Only the radial face of the cutting edge.

[Erikgem]

The instructions for hand grinding drills were good. I am an old escaped metal shop teacher (now a jeweler) so I keep a few teaching aids. The pdf file can be printed and used in making a home made drill grinding gage. Just cut one out and past it on a piece of sheetmetal with spray adhesive. Cut it out with sheet metal shears. You can cut notches for the graduations with a jewelers saw or just scratch them in. You can then remove the paper or just leave it on till it wears out. The spacing on the graduations doesn't have to be perfect because you are only using them to make the two lips equal length. Don't forget, when grinding, never let the shank of the drill get higher than the point of the drill or you will lose your clearance.
Dave Anderson
Erik unique jewelry,diamonds, and pet memorial rocks

[keykeeper]

Erikgem,

That's a very helpful pdf file you provided. Thanks from everyone here.

Also, How about a thread over in the "Introduce Yourself" section of the forum, I'm sure you have loads of metal shop wisdom for us Newbie's here.

Also, your location would be helpful. Just update it in the user control panel.

Welcome to IFI.

-aaron c.

[Daryl]

Drill bits! Don't feel bad about being unable to sharpen them correctly (yet). The shop I work in is filled with mechanics under 30 who seem to only have the ability to create arrow heads with drill bits, or worse. Yes, at Tech School they are all instructed in this arcane art and are passed!!!!!!!!!!!!!!!!!!!!!!!! Strangely, after my days off, my first task in the shop is not to sharpen drill bits, but to make them so they will actually drill a hole. I don't use a gauge or drill doctor or assistant, just a decent, trued grinding stone and a piece of graph paper. The real secret to sharpening drill bits correctly (or anything else worth doing) is to pay attention to what you are doing and to what the result is.
BTW, poor drill bits are a real pet peeve of mine.

[John N]

ive only just got the knack of grinding the small fellas (after many years in engineering!) - basically it will cut ok so long as when you eyeball it the cutting edge is the highest point! - if you can do big uns you can do the little ones with practice.

with the small ones, if they have been badly ground I sometimes find it easier to grind them flat, and start from scratch.

Dont let on to you know how to do it, or you end up grinding them for everyone else every 15 mins

[LDW]

If you clamp 2 hex nuts together in a vise that will give you a 60 degree angle to work with.