GTA
General Discussion To Gateway To Airguns => The Shop => : johncedarhill August 04, 2009, 08:34:43 AM
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I have a drill doctor and spent one hour unsuccessfully attempting to sharpen a 1/2 in bit for drilling recycled plastic landscaping ties. Seems like no large bit can be sharpened with a drill doctor. Is there a better way? 20 plus per pop is ridiculous so sharpening seemed like a good alternative but unsuccessful. I see where there is a large size drill chuck for 1/2 and larger bits to use with a drill doctor. Of course one brand new bit did not drill worth a "blank" either.
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You could allways sharpen them the old fashoned way - by hand. I have sharpened them that way since JR high school. My dad showed me how. A cheap bench grinder and a little patience. There is also a drill sharpening gauge for about $12 that helps get them perfect. I also have a drill doctor. It is the bigger one that can sharpen up to 3/4. I usually only use the drill doctor for 3/8 and under. It is easier and faster to sharpen the big bits by hand. Search the web for " sharpen a drill bit" you should get some good results.
Al
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I have felt that the doctor did a better job on the smaller drill bits.
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A regular grinding wheel works great. Use the fine stone. Make sure your pitch is correct for wood or metal.
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LOL. When I was building my house I thought I'd get one of these. Yeah it was fun sharpening all those bits I had laying around for years. Then like you I got to some bigger bits. I have one 1/2" in my tool belt set that now is about 2.5" long! I kept going at it with the Drill Doctor to no avail. Kind of like sharpening that pencil down to a nub. So like you small bits work fine but it is a cruel joke on the bigger bits. I ended up sharpening it on the bench grinder.
So mine has been sitting there for about two years. Anyone want to trade for it???
Andy Wong aka larspawn
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Heres a little trick to get the angle right 32*...
on the rest plate of yer bench grinder mark a line
at 32* to the wheel face then grind a small groove
along it..For you to lay the drill in when sharping it...
and anything under 3mm toss in the bin get a new one
1/2' big ?/....try a 2 1/2"
Pete
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Well if I decide to try to rot out the tree stump I will need to drill a lot of holes. I might just try some free hand sharpening or get the sharpening jig from grizzly since I need some center drill bits too. What is really frustrating to me is the fact that new out of the package bits don't drill worth a hoot. I am glad I got the feedback about the bigger size bits not sharpening well on the doctor so I can save the cost of the bigger doctor chuck. I originally thought the bigger chuck might hold the half inch and higher better and the doctor would work well.
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I have a variable speed with one a cloth wheel for buffing. I like the slower speed for the lathe tools and I think the grinding wheel is an 80. I tried the white and pink wheels a few years ago but just did not like the way they sharpened the turning tools. There is probably no reason why a paste on sandpaper wheel on the lathe would not work either now that I think about it.
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Yup. I got the "bonus" package that came with the bigger chuck. Still doesn't sharpen bits bigger than 1/2.
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I don't think the pitch is right on the bigger drill bits when using the doctor.
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Drill bits require a different angle for drilling plastic than they do for metal. That much I remember from airframe & powerplant school.
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Well I bought the drill grinder attachment from grizzly. The jig is pretty clever but setting it up might be more difficult than I expected. Using the jig as intended limits the length to about six inches. The bits are much longer so I might just try my luck at hand held sharpening. The dull ones probably can't be made any worse.
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Johncedarhill, I had some dull ones too, and like you I figured they couldnt get any worse...in fact they sharpened up ok...a whole lot better than they were. I just used the grinder and a hand file. I found, just like everyone's sayin,that the large drill doctor attachment didn't work well at all. I'll have to check out that jig from Grizzly too. They still got them fancy catalogs? I cant throw my old ones away...they seem too pretty to me.
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Thanx Kiwi for helpin me figure out what that groove was for(sometimes I just don't know what happened to me!!!). There's one already on my grinder toolrest thingy. I could not figure out what that was. I didn't take a shop class when I was in school...just learned from what I seen others do.
Got to take a Soldering Class in the Navy though, along with my Electronics Schools. Back then I didn't think to save the Certificates you get when going through the military schools...but I'm a certified electronics tech and solderer...just cant prove it.(http://../jscripts/tiny_mce/plugins/emotions/images/smiley-smile.gif)
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Hi John,
I got a special drill for you, if it's not too late.
Unfortunately drills designed for metal are do not work too well on wood, especially when you are drilling end-grain . I used to have to hand drill a 7/16" hole in the lip of a 90+ lb steel tub about 28" in dia and a foot deep, the walls and bottom were over 1/2 an inch thick.
This was a second (manual) op for an indexing head, used on XXXBrandNameXXX Radiation treatment machine to focus the Radiation wave. The machines that rotate around ones body while lying on their back. The hole received a SS pin which oriented the 360 degree band that wrapped around it to the machine.
This hole had to be 1 1/4 inches deep and after hoisting that drum up on the Bridgeport mill, with the table ALL the way up and standing on a 6 foot ladder to drill these holes I was worn out and went thru three or four jobber bits a day.
The on-site tool grinder modified a split point drill for me, like this:
This is very simple to do with a bench grinder. Grind the trailing edge of the drill (Shiny ground section) back to where it cannot contact the material you are drilling (get it completely out of the way and back about an inch along the drill); don't try and sharpen the leading or cutting edge at all, just grind away the trailing edge, bit pointing upwards, leaving about 1/16 - 3/32nds of the cutting edge intact. You will not believe how fast this drill will go through mild steel. It will look kind of like a spade bit for wood now, but with a better angle, better steel and much sturdier.
The 7/16ths hole I had to drill usually took about 5 to 10 minutes. Depending on how new the bit was and how tired I was. I was drilling at chest height, with my elbows above my head, atop a ladder, it wore me out fast (not much downward leverage in that position). With the modified bit I had the holes drilled in a two or three minutes. Without much straining and with no resting; except to blow the chips out of the drill bushing in the hole locating fixture and apply cutting oil.
I still have this drill (11 years old now) and I never had to sharpen it, while I was working on these little parts. I have used it on wood, although I can't remember ever using it to drill end-grain, I am sure it will work much better than a standard drill would (less friction and better chip clearance). End grain is very tough to drill or turn on a lathe (usually on a wood lathe I'd drill a small hole to just under my finished depth and use scrapers instead of gouges to rout it out, though I'll start with a gouge untill the hole is too deep (these were round boxes with lids, not bowls)).
I hope this post wasn't too late; I just thought that it was a good tip to pass on, late or not, especially in loose tolerance operations (like knocking up quick jigs and spring compressors and drilling the occasional large hole in thick steel), although the bit did hold the +/- .001 dia. tolerance required (the locating pin was locktited in and usually had to tap it in with a piece of brass; it was tight fit).
I didn't read this whole post but I saw something about drilling stumps. Pouring plain old, heavy on the nitrogen, fertilizer works just as well as these so called stump removing concoctions. Rotting a stump is a long process either way. A backhoe works Great for removing stumps too, but last time I heard, dumping stumps at the local landfill cost $50 per foot in diameter (that was 16 years ago at a Golf Course). LOL
Good Luck, sorry I got carried away with too much information. That's the way I am though.
Roy
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Thanks--what you are describing reminds me of the way my set of norseman drill bits are sharpened. These are my special go to for accuracy drill bits. Also these flutes are super sharp. I try not to handle them without gloves. The more I look into this the more I feel that on the larger bits the heel of the drill gets in the way. There is more sliding than drilling. That suggests to me why the drill dr. no will not sharpen larger bit well.