PDA

View Full Version : Problems with Drill Doctor solved



PeteF
08-20-2010, 06:46 PM
Rather than hijacking a thread running here on the Darex I thought it better to start a new thread. This may be common knowledge but I hadn't seen anything about it, nor did the Darex rep know anything about it when I spoke to him at a show.

I have a 750x and like the split point facilities. When I first got the machine it worked like a charm, sure it's not industrial quality by a long shot, but I couldn't understand what all the bad reports were about. If treated gently I couldn't foresee any problems with it lasting a while and doing a reasonable job.

Soon thereafter the drills started being ground with negative relief and clearly didn't cut. Nevertheless the (incorrect) relief was symmetrical on both sides. Changing the "notch" the collet was sitting in helped a little, but something clearly wasn't right. I couldn't work it out as the only possible explanation was that the drill was rotated when it was ground. When I looked at it carefully I could see the "prongs" that are used to align the drill in the collet were gripping part of the shank of the drill that had been ground from splitting the point instead of the flutes as it should. There's not a lot in it, as it only JUST grips the wrong part. As predicted, it allowed the drill to be rotated within the collet. Whether that would be a problem to others may depend on the depth of cut set by the stop, I have mine set to just skim a little off each time I grind. It's clearly a design fault, as if the "prongs" gripped further up the shank the problem wouldn't occur.

In practice I've found the solution is to keep a finger on the end of the drill and use my finger tip to manually rotate the drill to ensure the collet is gripped at the correct angle. If anyone is having problems with a DD not grinding drills correctly this could be something to look into.

Hope that's of some use.

Pete

J Tiers
08-20-2010, 08:46 PM
The main problem I have seen is the fact that the alignment "prongs" seem to be made from old pieces of pallet strap that they must have cut off a shipment...... Not very sturdy, and seem to have shifted or worn.

That. and the fact that they ONLY work on "normal twist" . If the drill has ANY other twist than the "normal one" that the DD expects, it won't work.

Mine cannot possibly be gripping on the split, since I never USE the split.

Also, it grips the drill well back from the tip, at least a quarter inch, maybe more. Always has, so that hasn't changed. If the twist is different than expected, the tip will be at some angle other than expected.

As far as the split............... The collets are so loose in the tube on mine that the end of a smaller drill moves around a distance equal to about its diameter.... So when I try to split, I either get a split past the center, or it leaves a little square piece of the point in place. Getting a good split is not possible unless you are remarkably lucky.

I assume some of the other problems are also due to the sloppy fit of collets in the tube, but I have not spent the money to buy a new tube. I don't expect it would fix it, they SWORE that the collets were the problem, and sent me more, but there was zero difference.

PeteF
08-20-2010, 09:22 PM
G'day Jerry, I'm just relating what I found on my machine, other's milage may be different of may have a different set of problems. My machine is quite new, and I was sharpening the same bunch of drills when it suddenly started developing "problems", nothing else had changed. In hindsight I realise that initially I wasn't splitting the point, next sharpening when I started splitting the point on some drill was also ok, since one sharpens THEN splits the point. It was only when I went back and tried to sharpen with a point already split that I started seeing problems. Being new it's possible that the collet problems have been fixed as I certainly couldn't fault that.

I agree, the prongs are pretty miserable. I haven't seen any wear in the machine as yet but don't doubt it will occur. Just the same I think the market is very much pitched towards the occasional versus professional user and the price was certainly right. I bought mine from Enco and simply run mine on a step-down transformer. As I recall it was somewhere around US$150 on special, which I think is very reasonable. Here in Australia you can expect to pay more like US$400 for the same unit (except it runs on 230V). I doubt it's worth that. The next step up was a Taiwanese drill sharpener at around US$1000 here, a BIG difference from the $150.

A mate of mine says, "why bother, just throw away the bit". That's all very well, but firstly I find that good quality bits aren't cheap, even in sizes I'd use a lot of (3-8 mm). More the point is that invariable one doesn't throw the bit out and continues to use it even when it's quite blunt. Now days at the first sign the bits are getting dull I'll pop them in the DD and just touch them up which has made the whole process a heck of a lot more pleasant. EVENTUALLY I'll possibly go to a professional drill sharpening machine, even though in all honestly I really can't justify it. Even though the problem with my DD seems to be sorted, I still don't think it grinds as well as the factory grinds on new bits.

Pete

J Tiers
08-20-2010, 09:38 PM
Even though the problem with my DD seems to be sorted, I still don't think it grinds as well as the factory grinds on new bits.

Pete

I'm with you on that... I don't like the point that much either, but I have a couple bins of dull drills, and had a fine time filling up the drill indexes.... until one day it didn't work right anymore.

The DD point does not seem to cut as freely as the factory point. And for sure, I have not ground enough off to get in trouble with needing point thinning.

I really want to do a good 4 or 6 flat split point, and the DD isn't ever going to do that. More stuff for the list.....

radkins
08-20-2010, 09:46 PM
I have a 750 DD and after trying every conceivable bit of advice to make the thing work right I have decided it is a total POS and can never live up to it's claims! A total waste of money IMO. :mad:

gunbuilder
08-20-2010, 10:32 PM
I have a 750 DD and after trying every conceivable bit of advice to make the thing work right I have decided it is a total POS and can never live up to it's claims! A total waste of money IMO. :mad:
How much will you sell it for?

My model 500 works for me, but then I am only a less than rich farmer. I didn't want to say poor farmer or someone would think I didn't care about how well a farmer I was. Not a real Machinist.

Thanks,
Paul

v860rich
08-20-2010, 10:52 PM
I've had the old style 3/4" DD for over 15 years, sharpened a bunch of bits with it, and have never been disappointed with it's performance.
The people who are mfg it now are also easy to deal with. The jaws broke in one of my drill holders, last year, and they sent a replacement "no charge".

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

PeteF
08-20-2010, 11:03 PM
I'm with you on that... I don't like the point that much either, but I have a couple bins of dull drills, and had a fine time filling up the drill indexes.... until one day it didn't work right anymore.

The DD point does not seem to cut as freely as the factory point. And for sure, I have not ground enough off to get in trouble with needing point thinning.

I really want to do a good 4 or 6 flat split point, and the DD isn't ever going to do that. More stuff for the list.....

Huh, I wonder why? The actual mechanics are pretty simple, have you taken a good look at why? It's interesting how for precisely the same machine (I presume) some people report reasonably good success, others reckon it's absolutely hopeless.

The thing I like about the split point is the fact I can often take the finished size drill and bring it straight down on the punch mark, or for even rougher work where accuracy isn't a huge factor, straight down at a mark and have it start cleanly and without wandering all over the place. A big time saver.

I can't recall it being covered in HSM, but MEW had some excellent articles a couple of years back covering the theory, jigs and simple rests that allow multi-facet sharpening. If George hasn't covered it in recent times I think it would be of interest to readers. If you're keen to pursue that avenue in the meanwhile I can search back through my back issues and you should be able to order the appropriate issues to construct the appropriate bits 'n' pieces.

Pete

J Tiers
08-20-2010, 11:20 PM
"Precisely the same machine"

That's where I reckon the problem is. I mentioned that mine has at least 3 or 4mm shake of the drill point. No special wear, no broken pieces, no good reason for it. Not many report that, but perhaps they have not popped off that little cover over the wheel and looked. Dunno.

I have no doubt that the problem is the molding of the fiber-filled plastic pieces may vary, etc. The folks at DD mentioned that my particular date code range "was one of the best"......

For the life of me I can't imagine why a product made of molded (precisely molded, we presume) parts would vary by lot. If it was carved, the ones made by "old Walter" might be the best, but with molded parts, they all ought to be far more alike than peas in a pod, and with any sort of QC, they all ought to work the same...... but apparently they do not.

PeteF
08-20-2010, 11:35 PM
When you're grinding the bit moves around 3-4mm at the wheel? :eek: Yeah well that would do it! The way the collet is rotated and also rocked it's possibly a bit deceiving, but I think mine is quite solid in that regard, but will pay particular attention next time.

The splitting is however a bit of a lucky dip. It has to be absolutely spot on to get a good split. generally speaking it is, but I've also had a few duds ... though come to think of it as I write, there's a good chance they were also the ones that didn't grind correctly :confused:

J Tiers
08-21-2010, 09:35 AM
When you're grinding the bit moves around 3-4mm at the wheel? :eek: Yeah well that would do it!

yes they do..... and that is just "rattling", no movement of the receiver tube at all...... New collets, old collets, all same-same....

it's like the thing warped, or mold flash held it to begin with and this is now the "real" clearance.....

Oh, well, enough on that..... I need to get/make a "real" drill sharpener. The DD at it's best made a point I didn't like that much.

bob ward
08-21-2010, 10:09 AM
Thanks for raising this PeteF. I bought my DD750 for occasional HSM use thinking it would sharpen drill bits more consistently than I do by hand.

Unfortunately it just does not always work as easily or consistently as its promotion suggests it should, you can't just blindly follow the grinding instructions and end up with a well ground drill bit, you have to keep a close eye on what it is producing.

Like others, I find the DD sometimes grinds bits with a nice sharp edge but negative relief. When this happens I reset the drill bit in its collet by setting the depth stop to a minimum, and then rotate the bit counter-clockwise a smidgen in the holder.

So what is the next step up from the Drill Doctor? These are some drill sharpeners offered locally, presumably Enco/Grizzly etc sell the same models, are there recommendations for any of them?
https://www.machineryhouse.com.au/Products?stockCode=D111
https://www.machineryhouse.com.au/Products?stockCode=D112
https://www.machineryhouse.com.au/Products?stockCode=D115

moe1942
08-21-2010, 10:42 AM
I had problems with mine and I put it away. Stayed in a drawer for years. Got it when they first came out. Not long ago I pulled it out and decided that the collet was riding too tight in the sharpening tube. I chucked it up in the lathe and a little at a time smoothed and reduced the diameter of the collet shoulder that rides in the tube. Once I could turn it with little effort I sharpened a drill and got great results.

It's like a tool from HF. Once you tweak it a bit it will produce good results for the HSM..

radkins
08-21-2010, 10:54 AM
How much will you sell it for?

My model 500 works for me, but then I am only a less than rich farmer. I didn't want to say poor farmer or someone would think I didn't care about how well a farmer I was. Not a real Machinist.

Thanks,
Paul


I took the grinding wheel out to build another type of sharpener with but if I can find the rest of that thing I will give it to you since you asked and you are a fellow farmer. I might still have it, it has been several years, so I will look for it this week when I get back home and if I can come up with all the parts I will gladly send it to you-no joke. :)

saltmine
08-21-2010, 11:21 AM
I have a "Drill Doctor". It was the "top of the line" most complete and expensive set when I bought it. A long time ago (I suspect it's pretty old, as the thing is made out of carved dolomite and wood). I've never had a problem with it, aside from wearing out several abrasive wheels.

It's so old, I had to learn Egyptian hieroglyphics to read the instruction tablet that came with it. It has been converted from slave to electric motor, btw.

reggie_obe
08-21-2010, 01:38 PM
Are the drill collets on the Darex D4 or D5, significantly different than those on the DD500/DD750? I'll have to agree that the fit of the bit holder into the alignment "port" on the body of the DD leaves a lot to be desired. I've had success with my DD750 and as Forrest has pointed out, they do work if the drill bit is properly set up in the holder.

Marc M
08-24-2010, 03:50 AM
When I was working at a semi-trailer shop, we bought a DD750 probably around '99 or '00. Like many, it worked decently for a hundred drills or so before problems started creeping in, mainly the negative rake issue (the point splitter never worked properly from day 1). Being a trailer shop, the vast majority of drills were 3/16, 1/4, (rivets) and 17/64 (floor screws) so nothing very large. Any drills that were heavily damaged I ground free hand to get them close before finishing/spliting in the DD. The splitting feature was never perfect, always a bit of a nub in the center, but still they didn't walk too bad.

One thing I found was that over-tightening the 'chuck' caused the thin jaws to twist inside the chuck which would change the orientation of the drill causing neutral or negative relief. The effect was more pronounced the smaller the drill was. OTOH, if it wasn't tight in the chuck, it would then move while grinding causing all sorts of problems. The more the chuck body wore, the worse the problem became. Once I had figured out what was happening, I was usually able to find a balance between the two. As has been pointed out, the twist rate also made a difference in the point geometry so the standard settings wouldn't work.

I was able to successfully counter these issues by using altered settings of the 118*, 135*, and masonary setting 'ring' when doing the initial alignment of the drill in the chuck to compensate for the errors. I don't recall which way I went, but usually it was in between the fixed positions. If the initial grind was off, I'd move the ring a bit, re-chuck the drill in the new position and do another grind. I'd repeat the process until I got the proper relief angle. Since I was usually doing a handfull of identical drills, the overhead of screwing around to find the optimum setup wasn't too bad. For 1 or 2, it was a major headache and hardly worth the trouble.

I also constantly cleaned the chuck and the 'sleeve' it rode in to help reduce wear in the plastic cams and on the OD/ID of the chuck/sleeve. In addition, I sprayed silicone based lubricant on the chuck every couple of bits to help reduce wear and make it easier to turn. It made a big difference.

Another point I was always confused about was their use of a diamond wheel instead of CBN since HSS would be what the vast majority of users would be sharpening. I chalked it up to higher replacement wheel sales :rolleyes: .

A few years later, my brother bought a DD (the same older style one) and it turned out to be hideous. The chuck fit so tightly, it was difficult to turn which made smooth operation impossible. It was also out of round because thru a certain arc it was easier to turn, then start to bind. It never got used enough to display any other issues :mad: .

I finally got tired of all the screwing around and bought a real drill grinder - a Tru-Point off Flea-bay. Don't know much about it other than it looks like it was made in Spain. It uses individual collets for each drill (1-52, 1/16-3/4, A-Z) so no chucks to have to maintain. The point splitter works well and is pretty easy to get set. It wasn't cheap and it will probably never pay for itself, but to me worth every penny not to have to screw around for a half hour to poorly sharpen 1 drill in a DD. I also like being able to grab any drill out of any of my indexes (home, work, shop) knowing that it's got a sharp, reasonably accurate point. At some point I'll post a new thread with some pics of it and some questions about it's proper operation as I don't have a manual for it.

Marc -

J Tiers
08-24-2010, 08:34 AM
Like many, it worked decently for a hundred drills or so before problems started creeping in, mainly the negative rake issue (the point splitter never worked properly from day 1). ........................The splitting feature was never perfect, always a bit of a nub in the center....

One thing I found was that over-tightening the 'chuck' caused the thin jaws to twist inside the chuck which would change the orientation of the drill causing neutral or negative relief. The effect was more pronounced the smaller the drill was. OTOH, if it wasn't tight in the chuck, it would then move while grinding causing all sorts of problems. The more the chuck body wore, the worse the problem became. Once I had figured out what was happening, I was usually able to find a balance between the two.

I was able to successfully counter these issues by using altered settings of the 118*, 135*, and masonary setting 'ring' when doing the initial alignment of the drill in the chuck to compensate for the errors. ..............................Since I was usually doing a handfull of identical drills, the overhead of screwing around to find the optimum setup wasn't too bad. For 1 or 2, it was a major headache and hardly worth the trouble.


I finally got tired of all the screwing around ................................It wasn't cheap and it will probably never pay for itself, but to me worth every penny not to have to screw around for a half hour to poorly sharpen 1 drill in a DD.

Aside from the trailer shop aspect, your experience is identical to mine... I might have written your post.

Except that I have not got an alternative sharpener yet, but I DO have a couple bins of drills that need sharpened.

Ed P
08-24-2010, 09:02 AM
I bought a Drill Doctor when they first came out and never had any problems until, after many years, I dropped it on the concrete floor
and the new company that had taken over was unable to supply replacement parts. I now have a higher end Darex product that uses the same design collets only these are completely made of metal not plastic. The method I use on the collets is to put the bit in and tighten down completely, then loosen slightly. The metal fingers are now parallel with the bit and the bit will slide easily in and out of the collet even though it has only been slightly loosened. I then put the collet in the alignment port and allow the two metal fingers to grip the drill bit. The bit will quickly and easily rotate to the correct position. I will then grip the end of the bit and rotate it *slightly* to make sure the alignment is correct before tightening the collet for the last time. The drill bit must move freely in the collet so the two alignment fingers can do their job.

Ed P

oldtiffie
08-25-2010, 08:06 AM
I don't mean to hi-jack what is a good thread, but I do feel compelled to ask why a "DD" or similar is needed by so many people.

"In my day/s" both "then" and now, drill-sharpening by hand on a pedestal grinder and drilling on pedestal drill were and are still required fundamental skills.

I have two really good drill (and tap and end of end-mill cutters) sharpener accessories that fit - and came with - my surface and T&C grinders that I never use for sharpening drills as I can have it all done before I've mounted the attachment/accessory let alone used it and put it away again.

Some things are like scratching your right ear with your right hand, some are like scratching it with your left hand and others are like scratching your ears with your feet - or best not even tried.

I mark out and centre-punch just about everything that needs drilling as no matter how small the drill end "chisel point" is, it will "wander".

Very few drill chucks can get the point of a drill to run "true" and unless the drill is in very good condition, a lot of collets can't either.

No matter how well the actual cutting edges of the drill are formed and how well they work, that chisel point will "wander" until it wears its way through to forming a cone that the cutting edges can "bite" into and centre the drill on.

A centre-punch mark will pretty well "attract" a small drill - and keep it there. The marking-out as well as the centre-punch will soon show you if the small drill has "wandered off" (it rarely does). Marking-out and centre-punching are also basic fundamental and required skills.

I drill the centre-punch mark with a small drill - say 1/8" - either right through or to say 1/4" deep and then follow up with a 1/4" drill which is larger than the "core" diameter of what-ever the next drill is. Those progressively larger drills do not have the "core" or a "chisel-edge" to interfere with them and they get on with their job and follow the drill before them.

So very little "web-thinning" is required.

In the event that I have to drill on the mill, I just drill the "starter" (say 1/8") drilled hole. As the next drill will follow the starter/previous, I finish the drilling on the pedestal drill unless there are compelling reasons to complete it on the mill.

I allow enough clearance for any screw or bolt that has to fit the hole.

Boring or reaming are done on the mill.

The same applies to drilling on the lathe except that the drilled hole is usually started with a centre drill.

I have some really good lathe tool sharpening grinding accessories as well and unless I am grinding TC accurately, I hand-grind and hand-hone them as well - screw-cutting tools included.

If I were in a "production" shop or if I had a large number of larger drills to sharpen I probably would (have to?) get those drill-grinding accessories out and get some use out of them.

But in my small shop where time is rarely of any importance at all, I just take my time - and grind my drills by hand.

J Tiers
08-25-2010, 08:48 AM
Tiffie, because most folks can't sharpen a small drill evenly by hand.

AND YOU CAN"T EITHER.

Sorry, Tiffie, but your hand sharpened drills are ALL off-angle, and with varying relief. I don't need to see them to know this, and it isn't being presumptuous to say it.

They may be "good enough for you", but a good machine sharpened drill with a 4 facet split point is a dream to use. I sharpen drills by hand too. There is a way to get it "pretty good" almost all the time. But they are rarely 'right" although usually "usable" , making two fairly even swarf curls.

On top of that, you are really talking about developing excellent and stylish techniques of buggy whip handling and special flourishes. Many people see a drill as a tool, to be sharpened the most effective and speedy way so that the real business of the shop can be attended to. I believe they have a "point", pun optional.

A decent sharpener allows drills to be sharpened speedily, and accurately. What's not to like?

Even teh DD, when new, made sharpening a smallish drill a quick operation. Easy to burn through a bin of dull ones in a short time, making all sharp, centered, and quite usable, if not perhaps the ideal shape.

And, I might add, all drilling quite close to correct size, Close enough for most any purposes. Closer than an equal amount of time hand sharpening gets them.

TGTool
08-25-2010, 10:01 AM
Just to stir the pot on good drill point geometry I see the latest issue of HSM has ads for an outfit that promotes these drill points. Article here: http://www.icscuttingtools.com/pdfs/The-Perfect-Point-Drill.pdf

It looks like no bad idea for many purposes. They mention reversing steps for counterboring for socket screw heads since the drill leaves a small cone for the screw body drill to follow. All well and good, but it makes me wonder if it would be WORSE that regular drills in following a smaller hole.

A little poking around their site shows a couple drill sharpeners, one portable that presumably produces the standard point, and one that can do split point and multifacet split points. None apparent however that can reproduce their perfect point drills so what do you do when they dull? Resharpen to common geometry, replace them or send them back for rework? I'm not criticizing them for what they're doing and offering, but the juxtaposition of the resharpening thread makes it an obvious question.

Deja Vu
08-25-2010, 11:05 AM
Here's a sharpener I picked up cheap at a yard sale out of curiosity. After a lot of fiddling and a shim here and there I was able to get a few smallish drill bits to cut quite well with standard grind profile only. I figured the stone/motor alone was worth the effort to take it home. A big step down from the Drill Doctor. :rolleyes: Plastic parts flex, swivel is too loose, depth setting needs to be visually set.
http://www.plasplugs.co.uk/Images/sharpeners/drill-sharpener19.jpg
www.plasplugs.com

oldtiffie
08-25-2010, 07:43 PM
Tiffie, because most folks can't sharpen a small drill evenly by hand.

AND YOU CAN"T EITHER.

Sorry, Tiffie, but your hand sharpened drills are ALL off-angle, and with varying relief. I don't need to see them to know this, and it isn't being presumptuous to say it.

They may be "good enough for you", but a good machine sharpened drill with a 4 facet split point is a dream to use. I sharpen drills by hand too. There is a way to get it "pretty good" almost all the time. But they are rarely 'right" although usually "usable" , making two fairly even swarf curls.

On top of that, you are really talking about developing excellent and stylish techniques of buggy whip handling and special flourishes. Many people see a drill as a tool, to be sharpened the most effective and speedy way so that the real business of the shop can be attended to. I believe they have a "point", pun optional.

A decent sharpener allows drills to be sharpened speedily, and accurately. What's not to like?

Even the DD, when new, made sharpening a smallish drill a quick operation. Easy to burn through a bin of dull ones in a short time, making all sharp, centered, and quite usable, if not perhaps the ideal shape.

And, I might add, all drilling quite close to correct size, Close enough for most any purposes. Closer than an equal amount of time hand sharpening gets them.

I can agree with most of your points JT.

Sharpening drills by hand is like grinding lathe tools or welding - its a developed manual art/skill that takes time and practice - and a good critical eye.

My drill sharpener does do a very good job - as I said, and its a PITA to mount, set up, use, clean up and put away for a small number of drills - as I said. So I do them by hand - as I said.

Once I have the "pilot" hole drilled the following drills pretty well "self-centre" and because they have neither the chisel point nor the "solid core cone" of the following drills to contend with they just get on with the job of drilling a hole.

I don't worry too much too often about drills drilling a bit over-size - its very little most times - as drilled holes are not always required to be too accurate as regards size and finish but they are required to be straight and positioned/located fairly accurately.

If a perfectly ground drill point is not precisely "centred" when spinning in the chuck or collet when that perfect point first makes an impression on the job to make a cone the rest of the drill will follow as the drill regards and treats that initial contact cone just as it does a centre-punch mark.

Which brings me back to where I started.

If I really wanted a drill to be really accurate as regards size and location I would use a brand new drill out of a new package and located the drill by use of a precision-made jig or fixture - with replaceable precision-made hardened steel bushings or sleeves or guides.

While I can do all that if needs be I find that its rarely necessary on my work in my small HSM and hobby shop.

I work to a level of accuracy that is consistent with the degree of accuracy - and effort - necessary for the job in hand.

Hand-grinding of tools and marking out and centre-punching works well enough more often than not here.

It is most likely to be different for other people and other shops.

I quite openly admit that when I need to "web thin" I use the "corner" of my pedestal grinder (still the old an faithful "grey emery" (dark-coloured aluminium-oxide) wheel as well as a "Dremel" and larger die grinders. I also hack off the bulk of the "trailing edges" of the drill cutting edges as a crude form of "secondary relief" so that I have a lot less "primary relief" to grind or worry about. That "hacking" is done either on tjhe pedestal grinder or with the fast-cutting angle-grinders.

It sure may not be pretty but it sure as hell works (for me anyway).

It does seem that in many cases that many have bought these "Drill Doctors" and the like as a panacea for all drill sharpening ills and ailments only to find that it not only did not solve the intended problem but caused problems of its own.

These pics may assist some here as regards drill grinding. They are not and are not intended to be a complete answer but they go a long way towards getting good results.

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book2_P40-41_1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book2_P42-43_1.jpg