Sharpening Small Drill Bits

DafyddElvy

DafyddElvy

1:22.5 & 15mm Scale Trams, , NG Steam Railways
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My latest project requires quite a bit of small diameter drilling, around 1mm, does anyone have any experience of sharpening 1mm drill bits, please don't laugh.

Today a very small item, 4mm channel to 10mmx2.5mm brass strip, de-soldered when I went to drill a 1mm hole beside the soldered joint, 8 previous holes were drilled without trouble but the drill bit is blunt after only around 10-12 holes.

I have around 200 1mm holes to drill, and buying a new drill bit for every 10 or so holes isn't something I relish having to do.

As always any advice or suggestions appreciated, thanks.

David
 
DafyddElvy said:
My latest project requires quite a bit of small diameter drilling, around 1mm, does anyone have any experience of sharpening 1mm drill bits, please don't laugh.

Today a very small item, 4mm channel to 10mmx2.5mm brass strip, de-soldered when I went to drill a 1mm hole beside the soldered joint, 8 previous holes were drilled without trouble but the drill bit is blunt after only around 10-12 holes.

I have around 200 1mm holes to drill, and buying a new drill bit for every 10 or so holes isn't something I relish having to do.

As always any advice or suggestions appreciated, thanks.

David
Click to expand...
This may help.

Personally with such a small diameter I just buy packets of 10 at the hardware store the same as the tradies do.
Lot less mucking around.
 
I use have to sharpen drills (by hand) as part of my apprenticeship training, and though I now own jigs to assist as with GAP GAP and P phils2um I just buy a packet of the size and dispose of them when blunt. But be aware who you buy them from, not all drill bits are equal.
 
Trying to sharpen drills and keep the diameter correct isn't easy, on anything under 2mm is probably too difficult to even try. Buy packs and use the blunt ones for something else
 
Try the Whisbon-2
It sets the proper angles and provides a good grip on the small drill
3dladnik.wixsite.com

Wishbon 2 - A Tool for Sharpening Small Drill Bits | 3DLadnik

This tool allows you to quickly and efficiently sharpen drills with a diameter of 4 mm to 0.5 mm without any special skill. Made using 3D printing on an FDM printer, easy to assemble, inexpensive.
3dladnik.wixsite.com 3dladnik.wixsite.com
 

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Well, I have a knife sharpener, and freehanding the angle is tough, I don't see how that device also indexes the drill bit either, do you have to eyeball it too?

I do have a sharpener for larger bits, and it indexes the bit and sets the angle and the clearance angle.

Find one of those for small bits and I will buy it, I have numbered drills down to 80.

Greg
 
I would agree with all that has been said about sharpening such small drills: it is extremely difficult to get the angles correct, so even if you manage to get something of an edge back, they may not drill straight holes.

I have found that drill speed is crucial: run the drill at its fastest speed (a cutting speed of 75 M/min for brass would suggest 23000 rpm for a 1mm drill bit!); and if you can, use a bench-top pillar drill, as small drills don't appreciate side loads. And yes, use a bit of lubricant, although Mk1 saliva will be fine on brass.
 
Northsider said:
I would agree with all that has been said about sharpening such small drills: it is extremely difficult to get the angles correct, so even if you manage to get something of an edge back, they may not drill straight holes.

I have found that drill speed is crucial: run the drill at its fastest speed (a cutting speed of 75 M/min for brass would suggest 23000 rpm for a 1mm drill bit!); and if you can, use a bench-top pillar drill, as small drills don't appreciate side loads. And yes, use a bit of lubricant, although Mk1 saliva will be fine on brass.
Click to expand...
Angles are important, and I notice the tool is set for 118 degrees which is correct for steel, but should be different for other materials especially other metals (but we never bother to regrind), rake though is the most import thing, or more correctly back rake, without this a drill will never cut.

Cutting lubricant, lots out there, and again different lubrication for different metals, and in some cases the wrong lubricant can prevent cutting.

But all this (except rake) more relevant to larger size drills. So as said anything less than 2 mm, buy a box use till blunt and then throw away.
 
Well David I have been hanging back with an answer to this as I do have a device similar to that Wishbone posted by Gerard in fact it could even be one of them. Had it for years and worked quite well, but can I find it? No not a chance. Had a lit of serious searches in the last day ir two since your plee.
 
JimmiB, you are right with your remark "buy a box use till blunt and then throw away".
That is the solution for a lot of people.
On the other hand it is part of my hobby to renew a tool if possible.
As for the angles: the main angle 118 is covered well i think, the back angle is made by slightly tilting the tool each strike,
as can be seen in the video.
Finally the fact that you use the tool very slowly on a fine graded sandpaper makes it possible to control the process so both sides are equally treated.
 
I am wondering how hard the brass has become after the soldering process.
A High Speed Steel (HSS) drill bit should go through brass easily, perhaps David is using to high a speed which is hardening the brass even further and that is blunting the drills.

This person recommends;
A slower speed with lubrication to preserve the drill cutting edge.
Using a drill press (pillar drill) to remove the side load of such a small drill.
Consider using titanium coated drills, manufacturers claim that they will last longer
www.familyhandyman.com

12 Tips for Drilling Holes in Metal

For most DIYers, there will likely come a time when you'll have to drill through metal. Find metal drill bits for metal and methods used to do it vary.
www.familyhandyman.com www.familyhandyman.com

This chart shows the recommended speeds for different metals.
https://www.sserc.org.uk/wp-content/uploads/2011/12/drill-speed-chart.pdf
 
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How much are you paying for your 1mm drill bits?

Ten for £10.00,or £4.20 each?

The former, are for the likes of me, who breaks them..
The latter, are for people who blunt them, before breaking them.
 
PhilP said:
How much are you paying for your 1mm drill bits?

Ten for £10.00,or £4.20 each?

The former, are for the likes of me, who breaks them..
The latter, are for people who blunt them, before breaking them.
Click to expand...
Certainly plenty of options, just got a mixed set of 10 each of 6 different metric sizes 1mm-3.5mm in .5mm jumps x Amazon for £6.99.
 
I remember from my engineering days drills coming to the toolroom for sharpening on a specialised machine, on 1mm drill you are trying to grind about 20 thousandths of an inch per side...not worth the hassle for the cost of new ones.....
 
JimmyB said:
Bought something similar, when the shanks were mic'ed up there was some discrepancy in size, but only 0.1 mm
Click to expand...
Oh I think I could live with that, rarely that I do much true precision work and when I do I have proper ba and imperial drills for that.
 
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