Drill sharpener

Mainly because I've got better things to do with the time.

I do sharpen large drills by hand, but I do it so rarely that it takes me several attempts. As I mentioned in my first post, I sharpened every blunt drill I could find in about 1/2 hour which I reckon paid for the tool.

That is, of course, just a personal preference to which you are entitled.

Some here are profesional engineers working for money, some are cheque book engineers, and some are hobbyists. Each to his own.

Russell

I'm a hobbyist. My workshop is to support the hobbies, so a professional approach is necessary. Spending hours to make a tool that will only get a few minutes use per year when I can buy one for a few quid isn't going to happen.

I do understand that there are many ways of tackling drill sharpening but the purpose of this thread is really a question about using this particular piece of equipment.

I've been thinking about the problem I raised and an observation that my machine seems to want to take off too much material. When the amount of grind is reduced it seems to get it right. I have an idea I'm going to test tomorrow and if I'm right it will be about correctly positioning the grinding wheel on the motor shaft. It is designed to be adjusted.

I'll let you know how I get on

Pete

Hi

I have been working though this. Here are a series of drills I'd done with the machine out of the box. Either a flat relief or going the wrong way

I ground a pointer and installed it in the drill holder and offered the point to the grinding wheel

As I had suspected putting it into the setup jig the there was a gap between the end of the pointer and the touch plate in the jig.

Looking at it the other way round if a drill bit was set against the touch plate the extra material would need to be ground off before the grinding ceased. This would then mean that the cutting lips would be ground beyond the intended location on the flutes.

This should be easily resolved as the grinding wheel can be moved along the motor shaft. However, on my unit flat on the shaft, that the grub screw bears on doesn't allow the grinding wheel to be moved far enough. That is, after the pointer has been set to the correct length on the setup jig, the tip of the pointer should be just rubbing on the grinding surface.

I have tried with the grub screw being clamped directly on the motor shaft and not the flat and using the machine like this I get perfect results with drills from 3mm to 12mm.

I now need to work out how to get the split point to work. I think there will need to be a compromise between the position of the grinding wheel for the basic grind and the split point.

So when doing split point on the Sealey do you reset the drill bit in the jig after doing the basic grind? The Chinglish instructions that came with my clone don't advise to do it but some YouTube videos say you do.

Pete

Edited By Doubletop on 27/12/2018 02:41:19

I always reset the drill bit for the split point grinding, and get good results.

Gary

Thanks, now I have an idea of the orientaion of the drill bit relative to the grinding wheel and be able to do some juggling to get everything in the correct position.

I also thing I picked up somewet that these machines only do split point for drills 8mm and up, or was I dreaming that?

Pete

Theres a small video here which gives a demonstration **LINK**

Regards

Mark P - I have a Drill Doctor. Used once when first purchased some 5 years or so, ago. Drill size , maybe 6 - 8 mm and results seemed OK but innate laziness has taken over since!

rgds

Bill

Mark P

I also have the drill doctor and find it's hit and miss as to getting a good grind. But I must admit haven't persuaded it and it lies in the box on the shelf

Lionel

I have one of these Sealey units, and although I have many other designs of jig, find the Sealey very handy and quick to use. It gives a reasonable finish, and the geometry seems to work. I agree with your investigation which reveals the wheel might be in a better position along the shaft, because I had the same thought in relation to the split points. I find that the wheel is inclined to grind too much, and give a point which is gashed down the centre, leaving two peaks, which is not correct at all. The problem seems to be that the wheel needs to be shifted along the shaft. I made some measurements, and made a spacer, but I have not got around to fine tuning the setup (too many more urgent jobs). It's something I will return to, shortly, in the light of your own investigations.

I can't comment on the clones, but the Sealey is a useful device, and well enough made.

I use a T&C grinder for forming 4-facet points on larger drills, and they work well. However; the convenience of the Sealey and my other sharpeners means it is easier and quicker to sharpen a standard conical grind drill, especially since they usually go blunt just when you need them quickly.

If I was to choose the ideal setup, I would sharpen my drills from 3 to 6mm using a swing-style sharpener (Reliance or Picador) and the Sealey from 6 to 13mm. T&C grinder above 13mm.

Marcus

I have had a drill doctor 750x for a number of years. It has produced very good results. It has also produced absolutely crap results. More over the last couple of years. I've tried replacing the wear parts, but it's still inconsistent. I recently resurrected a Picador drill grinding jig and mounted it on the surface grinder. The results are far more consistent and take about a tenth the time that the drill doctor did.

The only thing the DD is good for now is splitting points, and it does a pretty crude job of that.

Anyone still use the"reliance"twist drill grinding jig? I was given mine by my old foreman about 50 yrs ago & sharpen drills for the lathe, the rest I do freehand as my Dad taught me many yrs ago

I have a piece of worktop on which is mounted a Reliance and a side-facing grinder which carries a type 6 cup wheel. It's my go-to grinder for drills from 3 - 6mm, and sometimes larger. I fitted a steel flat at the side of the 'foot', so that I can slide the Reliance in or out a little to accommodate drills longer than the jig's range of adjustment, while maintaining alignment. Works very well indeed. I have some 'Picador'-style jigs too, but they came along later, so the Reliance is still my favourite. The advantage of the Picador is that the drill projection is a constant distance, while the Reliance projection varies with the diameter of the drill (hence the need for adjustment of the foot, for much larger or much smaller drills).

Marcus

I've ground split point on 4mm drills and it works fine, but the ratio of split point size (SP) to drill diam size (D) varies with D.

If Dn = drill diam of n mm, then SP/D4 > SP/D8

I surmise that SP/D3 -> 1

Edited By Gary Wooding on 28/12/2018 08:42:18

For any-one else reading this here's another vote for this type using a bench grinder

I set it up to the side of a 80grit (fine) wheel. If you don't already have a bench grinder you could buy a bench grinder plus this type of sharpener for the price of the dedicated sharpeners and I get perfect results every time though smaller than 3mm gets a bit difficult. For small bits <3mm I buy branded Sherwood or similar split point stub drills as for starting holes and the difficult job of driling small holes they are far superior to cheap bits and only requiring the small sizes quite cheap.

There is no skill involved really, what is also useful is to cut a set of old drill bits with an angle grinder very short then re-sharpen as stub bits.