Potts Drill Grinding Jig

[JssParticipant @jss]

In MEW issue No. 241, on the contents page, there is a reference to J Hugel's drill grinding tables being available on this website. Does anyone know where they are as I can't seem to find them?

John.

[Roger HeadParticipant @rogerhead16992]

Jss, not sure if this is what you are after. There are several pdf files and 18 XLS files on the QUORN_OWNERS group at:

https://groups.yahoo.com/neo/groups/QUORN_OWNERS/files/Analytical%20methods%20by%20J.%20Hugel/

Roger

[peak4Participant @peak4]

Posted by Jss on 18/03/2016 15:06:08:

Peak4, did you manage to sort your problems? I have the set up instructions if you're still looking for them. Can someone who has one of these tell me where I'm going wrong?

John

John, sorry for not replying, I've only just re-found this thread now that it's been rejuvenated. Been having a rather busy time tying up my Dad's estate and trying to purchase a new house ourselves, so sharpening drills has been rather on the back burner.

A set of instructions would be appreciated for the Potts, along with a photo/diagram of what the drill locating detent should look like. I've tried a variety of shapes and sizes, but the issue seems to be;

A detent which sticks up far enough to locate a 1/2" drill, fouls the flutes of a 3/16" one.

Similarly a shorter detent for a 3/16" drill doesn't stick up far enough for a large drill..

The cheapo Picador style, die cast monkey metal, ones have an adjustable detent to allow for this, but my factory made Potts one has a fixed detent held in place by a 7BA screw. I can't imagine one is expected to have a box of different detents, so I must be missing something somewhere.

On the up side, it does seem to give a good sharp even drill, but with rather too much relief.

Regards

Bill

p.s. does anyone know how to configure a permanant signature on this message board?

[Björn BursellParticipant @bjornbursell]

Made one this last winter

**LINK**

[peak4Participant @peak4]

Posted by Bj�rn Bursell on 14/06/2016 17:24:52:

Made one this last winter

**LINK**

Looks like it makes a nice job of the sharpening, but unfortunately that's the only photo on that thread that I can see.

Any chance of a pic of the location detent on the business end?

Many thanks, and welcome to the forum

Bill

[Björn BursellParticipant @bjornbursell]

Guess you need to be registered to wiew the rest of the photos…

The plans don't really give a good clue as how advanced the front end should be in respect to the pivot point where it intersects the platform. went for the conclusion that a zero diameter drill would be ground at a zero radius with a zero degree relief angle..

Just took a few photos of the business end, can be found in my flickr album: https://www.flickr.com/photos/139032632@N06/albums/72157664126081755/with/27730070505/

 

 

Edited By Björn Bursell on 17/06/2016 16:57:02

[peak4Participant @peak4]

Thanks Bjorn, much appreciated. I remembered I has an account with that forum and re-set my password.

Pretty much the same as my original one, but I was finding that the spring steel detent on mine was catching on the core of the flute on small drills, if the detent was long enough to set 13mm ones.

Can't get your link to work yet, maybe it's still uploading.

Cheers

Bill

[Björn BursellParticipant @bjornbursell]

Hm.. this link works maybe?

**LINK**

[peak4Participant @peak4]

Thanks Bjorn, much appreciated.

For some reason, your Potts album wasn't showing previously. I may have been too quick off the mark and tried to view it whilst you were still uploading it.

The link in your earlier post now works fine. 

I'll have another go at making a detent later on and see how I go.

 

All the best

Bill

Edited By peak4 on 18/06/2016 15:12:49

Edited By peak4 on 18/06/2016 15:13:40

[JssParticipant @jss]

Hi Roger/Bill, my apologies for not responding sooner. I tidied away the drawings for the Potts jig some time ago and it's take a while to find them. Also this is my third attempt at posting this reply.

Roger I struggle with Yahoo groups. I thought that as I was a member of the Drummond lathe group I would be able to get to the link you posted. Unfortunately not, I have to be a member of the Quorn Owners group as well. If all else fails I'll pursue that. Thanks for posting the link anyway.

Roger here is the detail of the detent as per per the drawing from Wokings:

As for the instructions:

Hope these are of some help.

Regards, John.

[Roger HeadParticipant @rogerhead16992]

John, if you pm me your email address I will send you a copy of the pdfs.

Roger

[Neil WyattModerator @neilwyatt]

My apologies, I have just realised that I never uploaded Joerg Hugel's corrected PDF and spreadsheet.

You can now find them here:

Drill Grinding Geometry.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Neil

PDF copied to the iPad

… but the Excel plots look a little sparse in their calibration.

… will have a look on the Mac, later.

MichaelG.

[Tractor manParticipant @tractorman]

I have the drawings and set up instructions somewhere if ypu still need them. Mick

[ASFParticipant @asf]

I finally made a copy of the drill grinding jig from Model Engineer from the 50`S ? Not sure if this was the Potts or not? It has a fair bit of engineering in such a small item

Odd thing is, I can actually hand sharpen fairly well. But the fun is in the building I guess

Anyway I just need to make it look fancy (or not) and it does seem to work ok.

Oh, the guard is now back in place Just needed a little trim

[mick70Participant @mick70]

Which copy of mag old?

Wouldn't mind making one myself

Ta

[ASFParticipant @asf]

It was started around November 1951 ! in Model Engineer by Duplex.

[Author]

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