Thread: GMF drill sharpener attachment

The jigger with the spring would be to locate/ support the flutes of the drill. I'm guessing it should pivot some how in the knuckle with the label on it - does it or has it jammed (the screw in the side with the locknut is the giveaway - there would be a grove in the shaft with the screw to locate it but the lock nut not allowing the screw to lock things up)

Michael

Bob, it also needs a drill bit clamping system and a way to feed the bit into the wheel.

There was a thread recently about instructions for the generic version of that.

https://www.woodworkforums.com/f65/help-drill-grinding-jig-instructions-185884

This thread provided the following link which I believe may be of some interest to you.

http://www.model-engineer.co.uk/foru...p?th=95436&p=1

Dean

Geeze what are the chances of getting two random bits that fit together to make a set? Looks like a heavy duty spirulex type as the others have suggested. Keen to see what results you get from it as I have been temped by an old spirulex at a local store just to give it a go.

WOW what a great score yeah what's the odds of two piece of a tool at different times of the year only to find that they go together. Now you know we all want the dimensions so we can all make our own.

HI Bob,
I just came across this PDF on the Internet. If You go t page 1 it shows your GMF device or a similar model

Thanks guys - much appreciate the rapid response.

It looks like all I need to do is make an adjustable/indexable support for the drill bit.

Originally Posted by Burnsy

Geeze what are the chances of getting two random bits that fit together to make a set? Looks like a heavy duty spirulex type as the others have suggested. Keen to see what results you get from it as I have been temped by an old spirulex at a local store just to give it a go.

I just contacted the guy I got the grinder from and we have worked out how this happened. The fella I got the linisher from is a mate of the bloke I got the grinder from and they both got the gear from the same source at the same time. It looks like when they picked up the gear the loose piece of the sharpener inadvertently got put together with the attachments of the linisher. Still, good to get them together again

Originally Posted by steran50

HI Bob,
I just came across this PDF on the Internet. If You go t page 1 it shows your GMF device or a similar model

Cool, I was wondering how they set the length, a block with a dowel in it and a thumb screw for final adjustment, very clever. I see it is designed to go on the side of the wheel. There are conflicting manuals on these style jigs (especially the Chinese knockoffs) as to whether to set the cutting edge vertically or horizontally in the jig. I believe vertically is correct, however you would be better off setting the jig to grind on the top side of the wheel rather than the front centre side (as shown in the pdf) as that way your grinding marks will be across the cutting edge and not along.

Seems GMF were ahead of the times, I read a 6 inch reversible diamond wheel grinder was available for tool grinding.

Originally Posted by Burnsy

Cool, I was wondering how they set the length, a block with a dowel in it and a thumb screw for final adjustment, very clever. I see it is designed to go on the side of the wheel. There are conflicting manuals on these style jigs (especially the Chinese knockoffs) as to whether to set the cutting edge vertically or horizontally in the jig. I believe vertically is correct, however you would be better off setting the jig to grind on the top side of the wheel rather than the front centre side (as shown in the pdf) as that way your grinding marks will be across the cutting edge and not along.

It is my belief that positioning the drill bit at the top centre of the wheel side is the best position. I am going to use this position on a disk sander. The forum thread I linked to has lots of discussions about grinding position. Even using the front face of the wheel is discussed. This would produce a slightly concave cutting edge, but apparently not enough to be a problem.

It would appear that the angle is fixed on this unit Bob. Stuck with 118 deg. This is a pretty solid looking unit which can handle fairly long drills. I am looking forward to seeing the end result.

Dean

Originally Posted by Oldneweng

Bob, it also needs a drill bit clamping system and a way to feed the bit into the wheel.

There was a thread recently about instructions for the generic version of that.

https://www.woodworkforums.com/f65/help-drill-grinding-jig-instructions-185884

This thread provided the following link which I believe may be of some interest to you.

http://www.model-engineer.co.uk/foru...p?th=95436&p=1

Dean

I wonder if anyone tried to look at the second link I provided and found no useful information. I used this link today and found it somewhat confusing, as I had printed off most of the relevant pictures about 2 weeks ago to assist me with my drill sharpener setup and today found only confusing posts.

I have no idea what is happening. At first I thought I was not getting the pictures, but after a bit more investigation I realised that all the posts from the OP had been removed. What is left is meaningless. Sometimes funny things happen on the Internut.

I posted this in case someone was wondering what Carp I was linking to. I am glad I thought to print the pictures I have. They are only on paper. I will now scan them.

Dean

Originally Posted by Oldneweng

It is my belief that positioning the drill bit at the top centre of the wheel side is the best position. I am going to use this position on a disk sander. The forum thread I linked to has lots of discussions about grinding position. Even using the front face of the wheel is discussed. This would produce a slightly concave cutting edge, but apparently not enough to be a problem.

I've been working or rejigging the jig to be used in this way - but accurate alignment looks tricky so I don't know if it is possible to do this in a steady way yet.

It would appear that the angle is fixed on this unit Bob. Stuck with 118 deg. This is a pretty solid looking unit which can handle fairly long drills. I am looking forward to seeing the end result.

The angle is adjustable. Sorry I don't have a clearer picture but there is an adjustment bolt on the side pointed to by the arrow in this picture.

I missed that Bob. Makes it a bit more versatile. Nearly all grinding will be done at 118 deg included angle unless you wish to try different angles. I have read convincing discussions on using 135 deg or so. Being able to change the angle will enable you to sharpen a few other tools. Countersink drill at 88 deg?

One of the things I am looking at with my sharpener is setting the offset from the vertical pivot axis to the the drill bit pivot axis. On the cheap mass produced units like mine this is a fixed figure of around 6mm which is apparently suitable for (Offset = Drill diameter/13) a drill bit of 78mm diam. This was shown in the Forum thread that I have just mentioned. I have checked mine by clamping the vertical post of the drill bit holder (your first picture) in the lathe chuck and using a centre in the tailstock brought up close to see where the pivot point is in relation to the drill rest position (the centre of the angle). This is the offset mentioned. Your's looks to be pretty long. It may not swing all the way around in the lathe. All this was shown in the thread with nice clear pictures. The OP's adaptation used a bush with a eccentric bore to allow adjustment of the offset.

I can provide the pictures if anyone is interested, but the intensive research from the OP is apparently lost. This is a pity as he had looked right back to the very earliest designs of this type of device and provided quite a bit of technical information.

This is a bit frustrating to me, as when this discussion occured in the WWF thread linked to above a link to another forum thread was given initially. I was unable to get pictures from this forum. The thread in the second forum was then pointed out. These threads were both from the same person (Graham Meek). There apparently was a difference of opinion which resulted in him leaving the first forum. There was some friction between him and John Stevenson in the second forum. John was a moderator. Opinions do have a way of getting in the way sometimes.

Anyway, I am looking forward to how you get on with your sharpener Bob. It looks to be a man sized version of what I have.

Dean

Originally Posted by Oldneweng

I missed that Bob. Makes it a bit more versatile. Nearly all grinding will be done at 118 deg included angle unless you wish to try different angles. I have read convincing discussions on using 135 deg or so. Being able to change the angle will enable you to sharpen a few other tools. Countersink drill at 88 deg?

Thanks for that.

One of the things I am looking at with my sharpener is setting the offset from the vertical pivot axis to the the drill bit pivot axis. On the cheap mass produced units like mine this is a fixed figure of around 6mm which is apparently suitable for (Offset = Drill diameter/13) a drill bit of 78mm diam. This was shown in the Forum thread that I have just mentioned. I have checked mine by clamping the vertical post of the drill bit holder (your first picture) in the lathe chuck and using a centre in the tailstock brought up close to see where the pivot point is in relation to the drill rest position (the centre of the angle). This is the offset mentioned. Your's looks to be pretty long. It may not swing all the way around in the lathe. All this was shown in the thread with nice clear pictures. The OP's adaptation used a bush with a eccentric bore to allow adjustment of the offset.

I understand the blue text but not the green text

I can provide the pictures if anyone is interested, . . . .

Yes please.

You arsy bugger! Nice score. Simon