twist drill preservation

[hdwarner]

here are some proven tips from me on longevity of twist drills

When you purchase a brand new drill take an Arkansaw stone or some light sand paper and gently stone the face of the drill or the lip when these drills are ground new they have microscopic slivers that tear into large imperfections when drilling.

Try if possible to drill into another piece of steel when drilling through a piece { NO NOT INTO YOUR DRILL PRESS TABLE OR YOUR VISE } and don't completely drill through that piece either.

One of the most detrimental things that happens to a drill is when you drill through is that little thin section right before the drill breaks through gets so hot it anneals the hardened drill , were blacksmiths we know that right.

Be sure you have the correct speed for drilling , a slower speed is always better than a higher speed, if you have doubts.

Keep good pressure on drill ,

Another dulling factor is a drill that dwells

If you are using cutting oils this even worsens the dulling process. If you are not pushing the drill, think of the honing process, that is what you are doing honig the cutting edge away. A couple drops of oil is all that is needed at entry.

A properly dressed twist drill in a blacksmith shop, for what blacksmiths usually cut, will never need replacing just minor touchups. i have dressed drills on the job and drilled thousands of holes in mild steel with out any maintenance .

if there is any interest in this subject i will expand

[markb]

I'm 58 and have been an electrician all my adult life.

I just learned a least 4 things about drilling.

Please expand.

[triw]

I am willing to learn more. When I drill through steel I have wood under the piece I am drilling through. Is this wrong? Also can you expound one the "Another dulling factor is a drill that dwells"? Thanks William

[NateDJ]

A dwelling drill is one you are not applying enough pressure to in order to get it to bite. It will sit and grind (hone) itself until the tip is a round slag ball if you keep at it long enough. Even with good coolant, you have to keep steady presser on the bit.
I use cutting oil for coolant, with out it I will always burn up the tip on a drill long before I will with it. The drill press I am using is a 16 speed floor standing one and set on the lowest speed always. I use Marvel Mystery Oil and apply a squirt at the start then at the first hint of smoking afterwards.

[hdwarner]

wood is fine try using a very tight grain wood or even "nova ply"
i understand you can not always back your work up like drilling pipe or
on site eye beams , etc
but here is a grind that will minimise drill pulling when drill goes thru
and it lends itself for longer lasting , takes a slight more physical energy
but worth the expense for the results , recommended grind for brass also

grind the positive rake on the drill to nuetral rather than positive
rather than grind till you understand function , use a sharpening stone at first
a few swipes on the face is all you need
be careful not to wrap around to the margin of the drill
i will try to generate better pics on my cad system

drilling principles is one of the most important aspects of machining and
sometimes blacksmithing however somethings are overlooked

will expand

[ironrosefarms]

This is good stuff, keep it coming and please better pictures on the sharpening of a twist bit. It has always frustrated me that I seem to be able to sharpen anything except a twist bit.

[Warrigal]

I realise this an old thread and I'm a newbie but I would love to work out how to sharpen twist bits. I know I can put an edge on just about anything else. By hand or with a gadget.
*VIDEO* Carl demonstrating the Spyderco Tri-angle Knife sharpener | Camperland News
But Twist bits, never.
When Grandad passed I picked up his collection of British twist bits. Rusted up so they have been in oil for near on 9years. But I still don't knoew how to sharpen them properly.
Carl

[pjh66]

Hi handy little book that you can get from bolt shops called
"Engineers Black Book 2nd edition"
It show different angles, lip clearance, for different types of material the 2nd edition comes with a drill point sharpening gauge.
book has heaps of handy imformation. There is a trouble shooting section also. See how you go