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28th June 2014, 08:54 PM #16
Mmmm - the thread on MEM doesn't add much in terms of actually modifying the device - I now realize that he has added an angle section behind the eccentric, there is also a spring in there somewhere. Looks like all we are getting is in the photos in conjunction with a careful reading of his posts. He has alluded to a couple of modifications but without much detail.
I have copied the relevant posts from both threads and saved the photos - hope to get as much as I can from that.
Cheers,
Findlay.
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29th June 2014, 12:46 AM #17
I take it that you have access to the photos from both forums then? Maybe I should scratch that idea about gleaning a bit more from another set of photos.
What I have picked up.
20mm angle sits in existing angle for rotation of jig for more precision.
Rotating shaft sits in eccentric drilled cylinder. This adjusts the offset which is determined from chart. Offset values marked on top face.
A shoulder on top maintains height.
Beefed up clamp for this.
I am at a loss about the spring. (But then I was thinking this was on Gadget Builders Jig) Does the spring maintain pressure on the pivot?
A different clamp for the drill. This is good. Clamps on round part, not flutes. Need to make sure drill does not lift at front tho.
No means to set drill cutting edge vertical. This I don't like. Slows the job down. He is working on this tho.
The pivot should tilt towards the grinding wheel by 13 deg from vertical at the top. This needs to be adjusted as required on each unit.
I don't know how this is meant to clamp to the bench. T-Slot? I would extend the wedge outwards for mounting screws.
I would also have a screw thread in there to feed the jig in when setting position at the start of the job. That's just me tho.
A couple more things I have remembered.
When I screw the jig in towards the grinder at the start, I do it with the wheel stationary. Wind in until the drill bit is just grazing the wheel as you pivot the jig. Set an estimated allowance to feed the bit into the grinder based on the amount of damage/wear. Might be just backlash from the thread. Lock the stop knob tight. If there was more than just a clean up to do, such as a chip to remove, I would grind both sides of the drill to clean up then do both again with a minimum cut to ensure the final cut is as close to equal as possible. I don't grind off a heap, turn the drill around to do the same for the other flute then expect the two cutting edges to be equal
I have found a copy of the drawing shown in that first photo. It is on the Hemmingway Kits website. I think if you click on it a picture of the kit comes up, or something. If I am wrong I will go and do something to bananas, or maybe find it again. Just found it on Gadget Builders web page. It is just one page with the drawing, but none of the parts are identified, just numbered. There is another drawing on the Hemmingway site, of kit parts but I am not sure it is of any use. It is probably the angles on that other drawing that are important. If you can figure out what they mean that is.
Doing all this reading today has reminded me yet again of the articles I have read that explain why the 118 deg angle for drill bit points is just an arbitary figure that nobody seems to know the origin of. 135 deg is often quoted as being a better angle to use. Anybody interested can have a look at this page http://www.newmantools.com/machines/drillpoint.html. This is one of a number I have read. The pictures in this article leave a lot to be desired. It is available as a PDF. Maybe they can be enlarged enough to see, but I have my doubts. This makes the details a bit hard to figure, but the general concept is easy enough to understand. Worth trying out in my opinion.
Dean
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29th June 2014, 01:04 AM #18
Just for interest sake, here is a link to a video about the Gadget Builder Jig I am interested in making. https://www.youtube.com/watch?v=hDW-...ature=youtu.be. This will cover drills from 1/2" down to 1/16". The 1/2" limit is based on the ER20 collets used. Larger collets can be used, but the nut gets in the way because of its size. ER20 fits without problems.
Dean
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29th June 2014, 03:04 AM #19
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29th June 2014, 03:08 AM #20
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29th June 2014, 08:16 AM #21
I thought that Baron looked familiar.
Maybe someone can help me with another problem. I would like to get hold of 2 issues of MSM Magazine which contain the articles related to the drill sharpener featured in the video I linked to in my last post. These are Jan and Mar 2012. How does one go about doing this. I have looked on the site, downloaded a list of articles and tried the search feature with zero success. The article search does not work for me. Says "Loading" for an hour with no result. As I could not even find "2012" in the Excel list I downloaded I am assuming it is not quite up to date.
I have just found the March issue in back order. What is the best way to get the January issue? Only a US phone number is supplied for issues not available as a back issue.
Dean
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29th June 2014, 08:41 AM #22Philomath in training
- Join Date
- Oct 2011
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- Adelaide
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29th June 2014, 10:09 AM #23
That would be helpful Michael. The cover story in the January issue is the project I am contemplating. This is continued in the next issue. John's website has lots of pictures and discussion, but not specific plans and instructions. I could figure it out, but I would prefer to have the plans/drawings.
What do you suggest?
Dean
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29th June 2014, 12:46 PM #24
Yes, I can see both sets of pictures. There are a couple of new ones on the MEM site.
I believe that the spring is to maintain pressure on the pivot as you surmise.
From MEM, Post 12;
The modification to the base vee is shown in the opening post in the "close-up of the eccentricity scale", a piece of 20x20x3 mm BMS angle has been fixed into the existing vee and the original retaining plate replaced. The post nearest the camera stops the plate from moving when rotating the new eccentric. Hidden from view a spring is fitted between the plate and the base casting to provide a means of adjustment.
I have a few drill that I modified years ago to somewhere around 135 deg. I usually use them for sheet metal & stainless. They work well. Maybe I will dig them out and try them in general use.
Cheers,
Findlay.
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29th June 2014, 09:08 PM #25
Re the spring. " Hidden from view a spring is fitted between the plate and the base casting to provide a means of adjustment."
That sugests to me that the spring is pushing out, which is not going to do a lot except steady the plate. I don't understand this, but I don't think it is really all that important.
I have read a number of articles over the last few years regarding drill cutting angles. Some of them make the Mazoff article look like a walk in the park. They make some good points. If you have not read the Mazoff article, one of the points he made was that by changing the angles ground on drills to his specs the Ford motor company recorded an increase from 8000 holes per sharpen to 30,000 holes per sharpen when drilling cast iron.
The simple fact is that the cutting edge on a 118 deg drill point is longer than that on a 135 deg drill point. This means that the 135 deg point cuts less material. I have not tried it yet, but I intend to.
I did manage to find my sharpening jig today and I did a quick check on the angle. It is around 8 deg lean so it needs an extra 5 or 6 degree wedge added. First I need to organize a stand for the grinder or sander. That is all I had time to do. Other work on the property took precedence.
Dean
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30th June 2014, 02:50 AM #26
Hi Dean,
It would be interesting to have a look at those articles and see just how much new information they contain compared to the web site. I suspect that the print version is fully dimensioned, where the web only gives a description. I note that several authors do this sort of thing, using the web as an advertisement, either for a magazine article or for a book.Best Regards:
BaronJ.
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30th June 2014, 08:15 PM #27
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1st July 2014, 03:49 AM #28
Hi Dean,
A number of years ago I wrote several articles for a couple of magazines. The general rule was if you got paid they, the magazine, took ownership of the copyright. This meant that even if you wanted to give it away or use all or part of the article somewhere else, you couldn't legally do it. I did have a row with a magazine at one point ! They took part of a paid for, by me, advertisement and created an article using some of that advertisement along with other similar products. It was a bit naughty of them, but we agreed that I would get a free ad entry in the next issue as compensation. I stopped advertising with them after that.
I've no problem with individuals using my work for non commercial purposes. But I do get a bit when it gets plagiarised and claimed as someone else's work, then sold, for someone else to profit from it.Best Regards:
BaronJ.
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1st July 2014, 10:11 AM #29
Ok. Full copyright. Fair enough if the author gets paid a fair price. That would limit future publications by the author. The only articles I have written have been for a dog obedience club newsletter that I was publishing, printing and distributing. I didn't worry about copyright. LOL
Dean
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2nd July 2014, 03:10 AM #30
Hi Dean,
When you are publishing your own stuff it only matters if a third party decides to use it commercially. Clubs and the like often don't give much if any thought to whether what they publish has any value to a third party.
As far as remuneration is concerned, I once tried to get a magazine publisher, the same one as I mentioned, to agree to give me further payments if they reused anything that I wrote for them. The short answer was NO ! The argument was that, as far as they were concerned once I'd got my £60.00p the article was theirs to do as they wished with.
I very much lost interest in doing any more writing for anybody after that...Best Regards:
BaronJ.