# Let's Talk Drill Bit Grinders!



## Weldo (Feb 9, 2020)

I've been wanting a good drill bit sharpener for a while now.  I'm sorta OK at grinding them by hand but I often can't get them perfect.  Sometimes my holes end up oversized or I only get 1 side producing chips.  Also it's tough for me to sharpen the small ones, like 3/16" or 1/4".

Cruisin' around ebay I find all kinds of machines at all kinds of prices.  Some are old vintage grinders and some are sparkling new Chinesium.  I kind of like the old Lisle 91000 but it only does 118 chisel points I believe.  The newer Darex grinders can do multiple angles and split points.  I like the Darex V390, which is kind of a glorified Drill Doctor, it seems quick and easy to use.

So any of you guys have opinions or thoughts on the subject?


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## ddillman (Feb 9, 2020)

I have a newer drill doctor works ok. smaller than 1/8 can be a pain to get aligned properly.


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## Weldo (Feb 9, 2020)

I think the Drill Doctor is a good concept but since it's marketed towards the DIY and homeowner market it's not very robust.  Darex makes a few different grinders that work on the same principle but are much more solidly constructed.

What about machines like this...







If I'm not mistaken, it seems this type of machine is based on the old Deckel design.  Most, if not all, of the new machines on the market are from China.  They look to be of decent quality and I like their versatility.  With the included attachments one can sharpen twist drills, end mills, and even HSS lathe tools.  I suppose you could even use it to do some grinding on parts if you needed to, say grinding a closely controlled flat spot on a small shaft or something.

These type of machines look like they can do a lot.  Does anyone have experience with one?


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## Chewy (Feb 9, 2020)

Drill doctor that takes up to 3/4" Sharpened a coffee can full of 30 years of dull drills. That can alone paid for the machine. It's noisy but good.


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## pacifica (Feb 9, 2020)

If you have a grinder(I use a belt grinder with 120 ceramic belt) this unit is available on ebay and made in usa for $10 -20 and works very well for up to 1". It's almost as fast to set up as by hand and is extremely accurate. Drill bits only. Handles to 3/32. Under 3/32 by a dozen drill bits and replace as needed. 
Won't sharpen the helical flute.


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## Shootymacshootface (Feb 9, 2020)

pacifica said:


> If you have a grinder(I use a belt grinder with 120 ceramic belt) this unit is available on ebay and made in usa for $10 -20 and works very well for up to 1". It's almost as fast to set up as by hand and is extremely accurate. Drill bits only. Handles to 3/32. Under 3/32 by a dozen drill bits and replace as needed.
> Won't sharpen the helical flute.


I have had one of these new in the box for over 25 years, and just last week I finally set it up in front of a dedicated grinder. I tested it by sharpening a 3/8" a few 1/2" and a 7/8" drill bits. They all came out way above my expectations. The one 1/2" drill bit that I tested cut really well and very even. I will take some pics later.


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## Weldo (Feb 9, 2020)

I've been using a Kalamazoo sander like this one when I sharpen bits by hand.






The flat platen makes a nice surface for grinding.  @pacifica, Do you have any pics on how you set up that grinding jig on a belt sander?  I'll probably look into that thing!


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## BGHansen (Feb 9, 2020)

I have a Drill Doctor 400 and 750x. Both have held up well after over 500 bits through each.

Bruce


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## SSage (Feb 9, 2020)

I do lots of drilling and maintaining the correct tip profile is the real challenge for me free hand. I have tried the jigs for belt and wheel grinders with mixed results. The cheapo drill doctor with the coarce wheel is consistent but slow. It does get the job done though, I sharpen lots of 3/4" bits with mine. What I like about my Drill Doctor is the straight consistent holes, it works, you don't need to spend anymore unless you need more speed or bits over 3/4. I've put countless cobalt bits through it. Haven't burned it up yet. When it gets real slow, change the drum stone thingy.


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## Weldo (Feb 9, 2020)

Hmmm, now you guys got me thinking about the Drill Doctor more seriously!  I always thought is was kind of a gimicky thing but it looks like it's capable of pretty good performance.

I'd like to be able to sharpen drill bits more accurately but I don't do it a lot so maybe the Drill Dr is a good solution for me.


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## projectnut (Feb 9, 2020)

I can't say I'm a real fan of the Drill Doctor, even though I've had one for many years.  They're OK for occasional use, but since they're 90+% plastic they will wear out considerably sooner than one built for commercial or industrial purposes.  I must say I've slowed down in the last few years, but not that long ago I was sharpening 50 or more drills per month.  At that rate the Drill Doctor didn't make it even 10 years before it was worn beyond use.

Post #25 in this thread includes a picture of the Black Diamond drill grinder I now use.









						Which Drills to buy
					

I need to buy some drills (I understand you are not supposed to call them drill bits).  I was looking at drill sets rather than individual drills.  They have inch/metric.  Also have drills lettered from A-Z and some listed as wire size.  There are jobber drills and screw?? drills.  Some sets are...




					www.hobby-machinist.com
				




If you can find something on this order it'll last a lifetime.  There are often several available on eBay, but don't get too hung up on the prices.  They generally run in the $8,000.00 to $10,000.00 range new, but often sell for peanuts on the used market.  I have seen several in the $300.00 to $500.00 range.  Mine will sharpen  fractional drills by 1/64" up to 3/4" .  It will also sharpen letter drills A through Z, and number drills 1 through 60.  If you go looking be sure the one you select includes a complete collet set.  New collets from Black Diamond are about $55.00 each.


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## Shootymacshootface (Feb 9, 2020)

The drill is indexed by an adjustable pointer on the flute. Then sweep the cutting edge back and forth to sharpen. The drill must be turned 180* per adjustment. Repeat until the entire end has a new surface. Pretty simple and not expensive. 
Tubalcain did a comparison of several different drill sharpeners and if I remember correctly, he was very impressed/ surprised by this one.


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## Weldo (Feb 9, 2020)

Yea, I do see those type of machine on ebay often.  Like you said though, it's very important to have a full, or nearly full, set of collets and many of the ones for sale don't.  I guess they don't use a standard ER type collet, huh?

When looking for a machine I tend to want the heaviest duty piece I can afford.  I don't like chinsy stuff and I'm willing to pay a bit more or shop the used market for something of better quality.  However if I'm honest about the amount of bits I sharpen or how much work I actually do, I could not justify buying a machine like the Black Diamond, Darex, or the like.

I'll probably start by playing around with one of the stand alone jigs like pictured above by pacifica.  The entry fee is minimal and the theory behind the jig is the same as well known grinders like the Lisle 91000.  I think I can rig it up to my belt sander and give it a whirl.

If that doesn't work out I may pop on a Drill Doctor.  With the amount of use I would give it I'm sure it would last at least a few years.


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## Weldo (Feb 9, 2020)

Shootymacshootface said:


> The drill is indexed by an adjustable pointer on the flute. Then sweep the cutting edge back and forth to sharpen. The drill must be turned 180* per adjustment. Repeat until the entire end has a new surface. Pretty simple and not expensive.
> Tubalcain did a comparison of several different drill sharpeners and if I remember correctly, he was very impressed/ surprised by this one.



Hey, thanks for the pics!  I think I will try that out!  I'm lookin at a unit on ebay right now!


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## middle.road (Feb 9, 2020)

Shootymacshootface said:


> View attachment 313165
> 
> View attachment 313166
> View attachment 313167
> ...


I've got a similar Millers-Falls that's sitting in a drawer. Guess it is time to put it on the 'To-Do' list.

What grit wheel is best to use with it?


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## Weldo (Feb 9, 2020)

Just bought a jig!  There are indeed lots on ebay.  I went for a Blue Point version because I like the blue color!  






Has the original box/instructions and looks like it's had little to no use.  Can't wait to play with it!


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## Shootymacshootface (Feb 9, 2020)

middle.road said:


> I've got a similar Millers-Falls that's sitting in a drawer. Guess it is time to put it on the 'To-Do' list.
> 
> What grit wheel is best to use with it?


Im using a 60 grit (medium) wheel. I removed the guard from the grinder and put an 8" wheel instead of a 6". I will use the front for large drills, and will move the attachment to the side (where it is flat) for small drill bits.


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## Shootymacshootface (Feb 9, 2020)

Weldo said:


> Just bought a jig!  There are indeed lots on ebay.  I went for a Blue Point version because I like the blue color!
> 
> View attachment 313170
> 
> ...


I know that mine went unused all these years because I couldn't mount it anywhere. Thats why I I finally put this dedicated stand together. 
Blue Point, nice!


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## Weldo (Feb 9, 2020)

I'll post up a pic when I figure out how to mount it!  I'm gonna try and use it on the flat platen of my belt sander.


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## Shootymacshootface (Feb 9, 2020)

The drill to be sharpened needs to stick out about 1/2 the diameter. The base is slotted to accommodate for this. I had to get a little creative on my setup to make this happen.


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## darkzero (Feb 9, 2020)

I've got a DD750X. It takes a bit of learning but doesn't take long to learn. It's loud but works well for what they cost. I have even sharpened carbide drills with it. Surface finish is not great but it sharpens well enough for them to drill well. I'm using the stock coarse wheel. The 750X does split points, looks different from factory grinds but again they drill well enough for me.

I also purchased the LH chuck but haven't tried sharpening any LH drills yet. The stock RH chuck says it works with up to 3/4" but I haven't been successful at sharpening S&D drills with it. No matter what I did it keeps grinding a negative relief. Maybe it's just the helix angle on my S&D drills, I don't know but whatever, I haven't tried S&D drills again.

Here's a HSS-CO drill that was really beat up that I did on the DD.











I wanted a real Darex or Lisle 91000 but none of the Darex models ever pop up used around here. The Lisles do occasionally but sellers ask for way too much money & they are always missing parts. There was a few used Sterlings that came up for $400-$500 ea from the same seller but I don't know anything about them. By the time I decided to go check one out they were all sold.

I ended up purchasing a OTMT branded MR-13D on sale for $500 last year from the local Travers. Comes with a CBN wheel & I purchased a SDC wheel for it. Uses ER-20 collets & goes up to 1/2". Relief & split point angle is adjustable as well as drill point angle. I haven't really used it yet though. Can buy the MR-13Ds directly from China for $300-$350.


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## Weldo (Feb 9, 2020)

Ah man, I think the Sterling machine is beautiful!  I've watched a few YouTube videos about them awhile ago and it seems like a great grinder!  It's got a really nice style too.  I'd love to have one!  As far as I can tell it operates just like the Lisle 91000.

I'm curious about some of the Chinese machines like the one you pictured.  Some of them can do end mills!  And I like the amount of adjustability they give you as far as point and relief angles and such.


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## Weldo (Feb 9, 2020)

Here's a pretty good deal on a Sterling!  3 phase motor though...

Sterling Drill Grinder

They claim it can do any bit from 1/8" to 2-1/2" and multiple point angles.  I love the micrometer style in-feed also!


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## C-Bag (Feb 9, 2020)

Weldo said:


> I think the Drill Doctor is a good concept but since it's marketed towards the DIY and homeowner market it's not very robust.  Darex makes a few different grinders that work on the same principle but are much more solidly constructed.
> 
> What about machines like this...
> 
> ...


I and several others on HM have those Deckel clones. These can vary in quality depending on who you go through. I bought mine on eBay and it was a mixed bag. I'm pretty sure the one in the pic is a direct clone in that it uses the same metric collets like the Deckel. Which for me didn't work because I wanted to be able to chuck up to 3/4" and the standard collets go to 12mm so it won't even do 1/2". I ended up getting one that uses R8 collets because my mills uses them and I had a complete set. In order to do drill bits you need the special attachment which the cheaper setup doesn't come with so there's a LOT of details to watch for. If I had it to do over I'd go with the U3 through Shars as it uses the 5c collets and has all the attachments. Around $1300 with shipping. All in I think I ended up around $750.

I've not done any drill bits yet but done many end mills and even a couple mill flutes. It takes some getting used to and creative problem solving but it's really nice to have. I never have to worry about stalling a job because a bit has gone dull. I got a handful of dull endmills with my old mill drill and was able to sharpen them all. It will do carbide and HSS with the right wheel. Made a couple of counter bores with it. Some custom grinds and made some custom dog point screws that were missing on my old shaper. Oh and found square ID 1/4" and 5/16" R8 collets for it and have done some precision ground HSS lathe bits for my lathe and shaper.


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## mikey (Feb 10, 2020)

Man, you guys are making me want yet another machine ... BUT I only sharpen drills occasionally and only for myself so my trusty old Drill Doctor (I have the old 500 model that does up to 1/2" drills) will continue to serve me well. It is accurate enough, does 118 and 135 points and splits them in a few seconds. I am only on my second wheel in, what, 25 years? 

If I ever do decide to step up to something else, it will probably be this one.


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## Weldo (Feb 10, 2020)

Shootymacshootface said:


> The drill to be sharpened needs to stick out about 1/2 the diameter. The base is slotted to accommodate for this. I had to get a little creative on my setup to make this happen.



I think the instructions say to drill a mounting hole 2-1/4” from the face of the grinding wheel.  Have you found that to be good or did you do something different?


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## pontiac428 (Feb 11, 2020)

Shootymacshootface said:


> The drill to be sharpened needs to stick out about 1/2 the diameter. The base is slotted to accommodate for this. I had to get a little creative on my setup to make this happen.



The extension (stickout) matters some, but there is a lot of wiggle room.  That's why you can have a permanent mount that establishes the distance between the pivot axis and the wheel face- which means by changing drill diameter, you need to change extension in order to reach the wheel.  Does this hurt anything?  Not really, according to Harold Hall.  It just changes the clearance angle.


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## Shootymacshootface (Feb 11, 2020)

Thank you for the graphics, very informative. 



Weldo said:


> I think the instructions say to drill a mounting hole 2-1/4” from the face of the grinding wheel.  Have you found that to be good or did you do something different?


The base of the grinding tool has a generous slot in it, so ballpark on that is ok.


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## pacifica (Feb 11, 2020)

pontiac428 said:


> The extension (stickout) matters some, but there is a lot of wiggle room.  That's why you can have a permanent mount that establishes the distance between the pivot axis and the wheel face- which means by changing drill diameter, you need to change extension in order to reach the wheel.  Does this hurt anything?  Not really, according to Harold Hall.  It just changes the clearance angle.
> View attachment 313338


Also if you first grind a full flatter clearance angle, then partially grind a tighter clearance angle (it helps to use a stop) you can create a 4 facet grind. I have done it and it works, but I did have to use a stop for accuracy of the secondary facet.


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## pacifica (Feb 11, 2020)

Weldo said:


> I think the instructions say to drill a mounting hole 2-1/4” from the face of the grinding wheel.  Have you found that to be good or did you do something different?


I drilled 3 holes since drills over 1/2" can be very long.


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## Weldo (Feb 11, 2020)

This is all great information!  Thanks to everyone for sharing!



pacifica said:


> Also if you first grind a full flatter clearance angle, then partially grind a tighter clearance angle (it helps to use a stop) you can create a 4 facet grind. I have done it and it works, but I did have to use a stop for accuracy of the secondary facet.



So if I understand the way this jig works, you'd grind a full sweep on each cutting edge with the minimum (recommended) drill bit extension, then you would reposition the jig a bit further AWAY from the grinding wheel and INCREASE the bit extension to meet the wheel.  Then you would grind about 80% of the rear cutting edge.  And you would end up with something like this...







Is that right?


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## pontiac428 (Feb 11, 2020)

That is a beautiful picture of a 4-facet grind.  This grind is great for spot drills.  If you have a high relief angle (from having short stickout on your Blue Point/Craftsman swing fixture), then you could grind just the primary reliefs similar to what you describe and be done.  It would be my preference to do this on some sort of fixture grinder with an indexing head.  Then you can dial in 5 degrees for the primary relief and whatever you want for the secondary relief angle, never needing the swing fixture.  What I do is grind the secondary relief first at around 12 degrees, then make a chip clearing relief that removes the tail of the flute as viewed from the front, and lastly grind in the primary relief that makes the cutting edge.

I'd like to point out that what I call swing fixtures do a really good job for your general purpose bits, and are very fast to set up and use.  When you start grinding facets, precision becomes more important, so a cutter grinder is the better tool for that.  Either one will make sharp bits, so at the end of the day the guy who spent $35 on a swing fixture will be drilling holes just as happily as the guy who spent $1200 on a cutter grinder.


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## Shootymacshootface (Feb 11, 2020)

Weldo said:


> This is all great information!  Thanks to everyone for sharing!
> 
> 
> 
> ...


Wow! I am going to do some experimenting with my grinding fixture.


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## Weldo (Feb 11, 2020)

I think I get what you're saying.  So first you would grind a higher relief angle then the cutting edge.  If you do your secondary relief at 12* what is the cutting edge?  Something like 5* or 8*?

I believe you are suggesting to use the pivot jig ONLY for the secondary relief angle and then use a much more closely controlled method to establish the actual cutting edge.  Is that correct?


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## pontiac428 (Feb 11, 2020)

Weldo said:


> I think I get what you're saying.  So first you would grind a higher relief angle then the cutting edge.  If you do your secondary relief at 12* what is the cutting edge?  Something like 5* or 8*?



Yep, I use the same geometries as an end mill on a 4-facet grind.  The primary relief forms the cutting edge along with the flute, and 5 degrees is the most common angle I see in the books.  The secondary relief can be anything, but 12 degrees seems to work for most materials.  Drill feed rate over RPM is what really determines what the angle needs to be.  It's not critical, I've actually made the secondary relief very steep experimentally, it drills the same and clears chips better, but if you remove too much material from the secondary face the drill's rigidity and cutting edge support is compromised.  So I stick with 12 degrees.  The third relief, what I call the "back cut", can be totally random since all it is there to do is allow chips to clear.



Weldo said:


> I believe you are suggesting to use the pivot jig ONLY for the secondary relief angle and then use a much more closely controlled method to establish the actual cutting edge.  Is that correct?



Yes, basically.  The swing fixture actually faces the bit with a curved sweep from cutting edge to back cut, starting out shallow at the cutting edge and sweeping steeply to the back cut.  That's what makes them fast and effective to use.  To grind a primary relief facet to a bit sharpened with a swing fixture, you would be best served to use an indexing head for the second operation.  Of course, you could do it freehand or in any number of shop-made grinding fixtures.  I usually don't work this way, either I use my Drill Doctor for small bits and split-points, or a swing fixture for large bits, or I use the cutter grinder and grind a true 4-facet pattern with a back cut.  There are many viable ways to arrive at the same result, so I wouldn't say one way is more correct than the other.


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## Shootymacshootface (Feb 11, 2020)

I have about 3" from the face of the wheel to the hold down bolt. When I move the fixture to the side of the wheel it will be much closer for the small drill bits.


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## Weldo (Feb 11, 2020)

Thanks for the explanation @pontiac428!

With my equipment I'll probably have to stick standard sweeping geometry but I expect that to work out just fine.  The drills I'm working with are from a cheap Harbor Freight set and they are so abysmally bad from the factory.  Almost every single one in the set of 115pcs had the heel end proud of the cutting edge.  I don't know if that would be positive or negative rake but it's the exact opposite of what you need!

Even just a little touching up by hand and they cut pretty decent so I can't wait to set up a proper jig.


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## rwm (Feb 11, 2020)

I had a Drill Doctor. I did not like it at all. The plastic was very flexible and trying to get a very precise split point was impossible. I am confused by some of the terms and claims. The 4 point facet grind shown above looks beautiful. I don't see these machines doing this. For example, here is the grind of the Cuttermaster:





This is a similar grind to the Drill Doctor as would be expected since they use basically the same technique. This pic differs from  the 4 point grind:





I have found that if the secondary relief does not meet exactly at the center, the drill will not penetrate without a pilot hole and it will tend to skate. That was my problem with the Drill Doctor. Am I missing something here?
Robert


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## Weldo (Feb 12, 2020)

Whoa!  I had to google cuttermaster.  Man that’s some nice stuff!  I’ll lodge that away in my memory in case I can ever afford one of their machines.  Cool stuff, and lots of different machines from end mill grinders to tap sharpeners.  I didn’t even know that was a thing!

In talking about relief angles. 

What’s really the benefit of a 4 facet over a standard curved type grind.  Do they not both achieve the same end?


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## pontiac428 (Feb 12, 2020)

Here is a short but well-written primer from Joseph Mazoff, a subject matter expert on drill point geometry, that should help cast more light on the subject.  Tubal Cain and Harold Hall both do a good job in their respective chapters of the Workshop Practice series, which are in the downloads section of this forum.  I also like to read the various machine shop textbook chapters on tool and cutter grinding, some go deep while others cover the subject in brief, but the varying perspectives and illustrations help cement the understanding for me.  Total disclosure; I like to read.


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## rwm (Feb 12, 2020)

That's great information. I gather that the Cuttermaster and Drill Doctor are making modified split points? Which is great if you get the central chisel correct.
Robert


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## pontiac428 (Feb 12, 2020)

rwm said:


> That's great information. I gather that the Cuttermaster and Drill Doctor are making modified split points? Which is great if you get the central chisel correct.
> Robert



 Grinder geometry and the degree of dress that is possible with the tool grinder wheel will dictate what you can do.  It's a tough subject to get down into the weeds on, especially with the sea of nomenclature that's out there, but I think the split point you get with different setups comes down to three things. 

1.  Web thinning:  Makes the bit pointy and accurate by reducing the contact area of the part of the tool that doesn't cut (the chisel or web).
2.  Back cut and point splitting:  Reduces wander by web thinning and increases chip clearance with the back cut in one step.  This is what Cuttermaster and Drill Doctor are doing.  It is a true split point, but not center-cutting.
3.  Center cutting ability:  Requires the grinding wheel to have a very crisp corner and a precise presentation angle in order to create a new cutting edge where the web approaches center.  Instead of being close to center and square-ish, a true center cutting drill will have a complete cutting edge ground and relieved through the web and up to the center point, just like a symmetrical flute center-cutting 2-flute end mill.

For a hobbyist, chasing marginal gains has little in the way of payoff for the effort of splitting hairs, so this is all for fun.  At least that's my take on it, and this is coming from a guy who has no qualifications other than liking to grind his own tools.


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## pacifica (Feb 12, 2020)

Weldo said:


> This is all great information!  Thanks to everyone for sharing!
> 
> 
> 
> ...


It helps a lot to have a stop so the arc only goes 80%(for example) on both rear facets. I clamp a 123 block on the rest.


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## keeena (Feb 14, 2020)

@rwm - I had the same issue with my Drill Doctor 500: was never happy w/ the split-point. Also: the lip clearance angle seemed non-existent.

I dismissed those bench grinder drill attachments as hokey, but you guys have me rethinking...may give one a try.


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## middle.road (Feb 14, 2020)

mine... gotta mount it now.   
(oh, and then learn how to use it. Minor detail.)




	

		
			
		

		
	
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...


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## Weldo (Feb 14, 2020)

Whoa!  That thing looks professional!  Never saw one like that.


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## Weldo (Feb 14, 2020)

Got my Blue Point clone today!

Spent two hours in the basement crafting a mount, check it out!

Here's the original tool rest.  It's just sheet metal so it's got more flex than a drill grinder should have.  Also it placed the drill tip almost off the platen.






Here's the mount I made.  It's a 3/8" angle that someone years ago faced the two outside surfaces down to 5/16".  I found this in a bucket with a bunch of misc. tools with my lathe.  Can you believe I once contemplated throwing this in the scrap bin?!  I welded a flat bar to give me some room for two bolts.  All the holes in the big angle were existing.  I thought of welding them up but didn't want to risk warpage.  They don't harm nuthin'.






It mounts very solidly and perfectly square with two 5/16" - 18 bolts.






Here's how I bolted it.  The lower one is a factory flow drilled and tapped piece.  The upper one is a chunk of 1/4" flat bar, tapped.  No wrench needed!






The following pics show the jig mounted.  Instead of bolt and wing nut I just tapped the base for a 7/16-14 bolt.
















Turned out pretty well.  Haven't done a bit yet though.  After working all day and then 2 hours on this I'm gonna relax for a while!

One question on the use of the jig.  It says to stick the drill tip about 1/16" past the index tab, so to advance the drill into the grinding wheel are t you meant to use the threaded adjuster at the bit base?  This will change the bit stick out slightly.  Otherwise you'd have to move the whole jig until the bit made contact with the wheel, and that seems awkward...


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## westerner (Feb 14, 2020)

Weldo said:


> . And you would end up with something like this...


Beautiful grind, and a no doubt SHARP drill. How many holes do you drill?


pontiac428 said:


> For a hobbyist, chasing marginal gains has little in the way of payoff for the effort of splitting hairs, so this is all for fun. At least that's my take on it, and this is coming from a guy who has no qualifications other than liking to grind his own tools.


Exactly. I have been making stuff, welding, nailing, cutting, brazing and soldering, drilling and bolting for 40 years around here. The 750 Drill Doctor cleans up my mess of "freehand" sharpening just fine. I have the patience, and no need to drill hundreds of holes/week in a production shop. "Marginal gains" is the operative idea. 
I mean no disrespect. Sharp as razor drills, and machines and equipment to hold .0001 are a wonderful goal. Do we NEED that? Are you willing to spend the time and money to attain that? To what end?
I come from the construction trades. In that world, you learn very quickly that "If the customer likes it, and will pay for it, than that is good enough"
You can spend DAYS polishing a thing, and the Customer will not notice. I do not mean to imply that your plumber is looking to cut corners. I am merely saying that if the job calls for .01 tolerance, and the customer and situation demands no more, then why are you beating your head against the Shars Catalog chasing .0001? If your drill makes reasonably equal chips from each side, and does not SCREAM at you while you use it, is that not good enough for the Hobby Machinist?


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## Shootymacshootface (Feb 14, 2020)

Weldo said:


> One question on the use of the jig.  It says to stick the drill tip about 1/16" past the index tab, so to advance the drill into the grinding wheel are t you meant to use the threaded adjuster at the bit base?  This will change the bit stick out slightly.  Otherwise you'd have to move the whole jig until the bit made contact with the wheel, and that seems awkward...



I believe that is what they intend us to do. There aren't any micrometer dials on it, so just eyball everything. Once you start cutting, then you will want to carefully index both sides. Then sweep both sides the same way to get a drill thats cuts evenly. 
You will figure it out quickly.


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## middle.road (Feb 14, 2020)

westerner said:


> Beautiful grind, and a no doubt SHARP drill. How many holes do you drill?
> Exactly. I have been making stuff, welding, nailing, cutting, brazing and soldering, drilling and bolting for 40 years around here. The 750 Drill Doctor cleans up my mess of "freehand" sharpening just fine. I have the patience, and no need to drill hundreds of holes/week in a production shop. "Marginal gains" is the operative idea.
> I mean no disrespect. Sharp as razor drills, and machines and equipment to hold .0001 are a wonderful goal. Do we NEED that? Are you willing to spend the time and money to attain that? To what end?
> I come from the construction trades. In that world, you learn very quickly that "If the customer likes it, and will pay for it, than that is good enough"
> You can spend DAYS polishing a thing, and the Customer will not notice. I do not mean to imply that your plumber is looking to cut corners. I am merely saying that if the job calls for .01 tolerance, and the customer and situation demands no more, then why are you beating your head against the Shars Catalog chasing .0001? If your drill makes reasonably equal chips from each side, and does not SCREAM at you while you use it, is that not good enough for the Hobby Machinist?


No not really and yes that is enough, mainly - _* I would just like a little shop time*_!!!


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## Weldo (Feb 14, 2020)

westerner said:


> I come from the construction trades. In that world, you learn very quickly that "If the customer likes it, and will pay for it, than that is good enough"



This is good advice!  I'm also currently working in construction and sometimes I go overboard on tolerances.  I'll be fitting a piece of whatever and it's not quite exactly right and I'll be stressing over an 1/8"!  Meanwhile the painters are coming in two days to caulk and putty everything and there's not really even a reason to worry.

Then I go home and play around on my lathe and get jacked off that I missed an I.D. dimension by 0.002"!  It can be kinda tough to live in both worlds!


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## Weldo (Feb 15, 2020)

Ground some drills this mornin'!

Here's a few pics of results!

This is the factory Harbor Freight grind.  Pretty crappy.  The entire set is like this and some of the bigger ones don't even cut at all.







Here's that same edge after grinding in the jig.  Notice it still woops up a bit at the end of the relief.  Either this is because the jig is not perfectly set up (possible) or the drills are so poorly made (also VERY possible)






Here's the opposite cutting edge.  The jig settings were the same but there's no woop at the end of the relief, which leads me to think that these drills are just poorly tolerenced.






I've been resisting for years buying a full set of quality drills since they're pretty pricey for a whole set.  These HF drills seems kinda crappy but with a better edge they should be good enough for what I do.

I'm gonna try to use more stick out of the drill in the jig to get a bit more relief angle but I have to drill and tap another hole in my mount to get the travel I need.


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## Shootymacshootface (Feb 15, 2020)

One thing that I noticed after grinding several different drills is that some drills have a much thicker center section between the flutes. This makes a very wide point on the cutting edge. These drills will either need a back cut or just use them with an appropriate pilot hole.


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## pacifica (Feb 15, 2020)

Weldo said:


> Got my Blue Point clone today!
> 
> Spent two hours in the basement crafting a mount, check it out!
> 
> ...


My experience:


Weldo said:


> Got my Blue Point clone today!
> 
> Spent two hours in the basement crafting a mount, check it out!
> 
> ...


Use the threaded adjuster to advance the bit, usually small amounts so you don"t loose temper on the edges.I use 80 or 120 on my belt grinder.
If the drill is 3/8" or larger it doesn't seem to matter how far out it sticks out. If your changing the drill angle or putting a tip on a broken bit you might want to rough it to shape with a die grinder so you don't loose temper. I eyeball to make sure the cutting edge is vertical. I don't go above 220 grit, finer belts don't seem to make much difference. 
If you want to make a great drill, before sharpening put in your lathe and take a small amount off the shank, you can get tir down to .001 and drill shanks are unhardened. sharp bits with minimal runout are the key to straight holes.


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## pacifica (Feb 15, 2020)

Weldo said:


> Ground some drills this mornin'!
> 
> Here's a few pics of results!
> 
> ...


I sharpen myself and want a drill with known steel and small amount of runout, by the time you get to the end of a 
4" drill the runout can be considerable, and that will translate directly into inaccurate holes.


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## middle.road (Feb 15, 2020)

For grins and giggles, I taped up and repaired the manual that came with mine, scanned & OCRd it and uploaded it to the Downloads section.
Thought it might be useful.









						Millers Falls #7080 Drill Grinding Attachment - Instruction Manual
					

Instruction manual for a #7080 Millers Falls Drill Grinding Attachment. Pardon the tape marks, it had a hole punched clear through it.




					www.hobby-machinist.com


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## Weldo (Feb 18, 2020)

Some observations.  

I tapped another hole to allow my jig to be placed further away from the abrasive belt.  This time I tried about 1-1/4" drill stick out and set the cutting edges to be vertical by eye.  When I did this I got a very poor relief angle such that the cutting edge was ground nicely but about half way through the relief, the grind stopped making contact, thus leaving the heel proud of the cutting edge.

When the drill is set up against the index according to the instructions the cutting edge is not quite vertical, though it is close.  As you look at the drill tip the lower cutting edge is pointing to about 5 o'clock to 5:30.  This gave a satisfactory grind so I'll probably stick to that for now.  Set the drill just about 1/16" past the end of the jig and have lower flute contacting the index stop.

My drills are still coming out a bit asymmetrical like my above photos but next I'm gonna try a NON Harbor Freight bit and see what that looks like.

Also I noticed that to achieve the rigidity in the jig that I think it requires I had to crank down tight on the pivot screws.  It became a little tight to pivot so I think some light grease is in order.


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## mickri (Feb 19, 2020)

I have one of the swing type.  An original Craftsman that came in its original box with the instructions.  It works for me most of the time.  Once in a while I have to redo a drill that I have sharpened.  Lots of great info in this thread.  Might deserve to be a sticky so it doesn't get lost in the never never land of old threads.


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## Weldo (Feb 19, 2020)

Got some more bit pics!

This time I tried a drill that was unbranded but was stamped USA so I'm pretty sure it wasn't of Harbor Freight lineage.  It's 27/64" size.

Here's the bit as found, looks like someone had a go at hand grinding but it didn't go according to plan... or maybe it did, who knows.

The cutting edge curls over pretty bad on both sides.  I didn't try drilling with this bit before grinding it but I don't think it would've been very good.












Here's after grinding.  Set up was as per the instructions with the drill just about 1/16" past the end of the jig and the bottom flute touched up against the index tab.  The drill was advanced inward to the grinding surface with the adjuster screw on the shank end.

The whole process only took about 60 seconds probably.















In the last two pics you can see I'm still getting that slight rise toward the end of each relief.  The difference between this and the HF drills is that this one looks more symmetrical.  The slight rise is the same on both reliefs, so that leads me to believe the HF drills are ground slightly asymmetrically from the factory.

I'd like to eliminate that rise in the relief but I don't really think it's a problem.

Here's a few shots of a hole made with this drill right after grinding.

Material is 1/4" steel plate, drilled in a drill press at 620 rpm, no pilot hole.

First up is the entry point.







Here's the exit point.  Very clean break through, no de-burring was performed.







Here's a look at surface finish inside the hole, it's not great...  No lube was used.






It drilled very easily even with no pilot.  The hole was made in just a few seconds.  Strangely, after the drill had penetrated to full diameter, I observed a long stringy chip only on one side of the drill.  Maybe feed was too light?

Finally here's a few of the drill after making that hole.  No rubbing is obvious except at the chisel point.  The two rises in relief show no signs of contact with the workpiece.












All in all I consider that a success!  I'll probably try a few different point angles and see what happens.  Like I said, I'd like to eliminate that slight rise in the relief and I'd like to observe equal chips upon drilling but do far so good.


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## mickri (Feb 19, 2020)

The steel plate not being square to the drill might have caused you to only get one chip.


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## pontiac428 (Feb 19, 2020)

Nice job with the pics, the views from the side of the cutting edges are very clear.

I don't think the little kick up on the outer edge of the bit is an issue.  It looks like it comes from the flute profile, not from the grind.  You've already proven it's not a problem with testing!

Remember, the stickout defines the radius of the cylinder swept, so less stickout means a tighter sweep and a higher relief angle.  It seems like the set point in the instructions for your jig gives a good result.

In the photo of the ground bit from the front, you can see ever so slightly that the cutting lip rolls off and that the cutting edges are bowed.  This indicates that the clocking/indexing of the flutes needs a slight adjustment to bring the cutting edge straight and avoid that roll off.

A little bit of fine tuning, and you'll be re-grinding factory sharpened bits because you know you can do better than mass production can!


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## Weldo (Feb 19, 2020)

mickri said:


> The steel plate not being square to the drill might have caused you to only get one chip.



Oh I hadn't considered that!  This drill press has a tilting table and one time years ago I meant to check the squareness of my drill press table to the spindle but I couldn't get the darn lock screw loose.  I'll have to revisit that.



pontiac428 said:


> Remember, the stickout defines the radius of the cylinder swept, so less stickout means a tighter sweep and a higher relief angle.



The trouble I had with this setup is, what should be the orientation of the cutting edge?  Since the stick out is not what the instructions recommend you can't rest the flute against the little index tab.  I tried to eye-ball the cutting edge in a vertical orientation but the grind was way off, nowhere near enough relief.



pontiac428 said:


> In the photo of the ground bit from the front, you can see ever so slightly that the cutting lip rolls off and that the cutting edges are bowed. This indicates that the clocking/indexing of the flutes needs a slight adjustment to bring the cutting edge straight and avoid that roll off.



I was gonna ask a question about this!  When grinding the bit should I try to not sweep PAST the cutting edge?  I wasn't sure if it mattered or not but I can envision when I sweep the jig from heel to cutting edge, that is the drill tip contacts the abrasive belt heel first and then sweeps TOWARD the cutting edge, if I sweep PAST the cutting edge it will probably roll it over ever so slightly.  Theoretically the cutting edge should break contact right at that tangent point.  I may be experiencing a tiny bit of spring in the belt because a belt riding on a platen is not as rigid as a solid grinding wheel.


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## pontiac428 (Feb 19, 2020)

With my jig, I start from the cutting edge and sweep to the back.  The point at which the cutting edge touches the wheel face will change if a bit needs any amount of grinding to restore its profile.  As you grind back into the bit, the cutting edge follows the flutes and the clocking of the bit changes, so I find I need to re-set the bit in the fixture to restore the relationship before finish grinding.  So I start with the cutting edge, which means I can establish the edge and its relationship to the flutes right away.  As I feed the bit in, I may need to re-clock the edge.  If I feed too much, I just end up with a facet that rolls off like you have pictured.  So the root cause for that result is clocking.

This diagram shows the result of being off of correct clocking with the cutting edge.  There's the bow in the cutting edge.  This bit needs to be rotated clockwise on infeed (as viewed from the back of the bit's shank) to correct.


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## Weldo (Feb 19, 2020)

So as the bit is fed into the abrasive I have to make sure that the flute is still up against the index stop?

I haven't been paying attention to that.  After the initial setting I was just merrily feeding the bit into the belt.  Gotta keep an eye on this!


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## Weldo (Feb 20, 2020)

pontiac428 said:


> Nice job with the pics, the views from the side of the cutting edges are very clear.



Thanks for the compliment by the way!  I picked up a macro lens for my micro 4/3 camera a few years ago for nature photography.  Who knew it would come in handy in the workshop!


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## Weldo (Mar 3, 2020)

Sharped a few more drills today!  These ones I keep with my work stuff.  I'm working in residential construction so they mostly see wood use.

The first is a 3/8"  Used to be a split point.  It sharped up well.







The next few pics are smaller drills, 5/16" and 1/4" and maybe a 3/16".  They went less well.  Geometry is kinda wonky...  The pics are of bits progressively smaller.  

5/16"











1/4" I think.






3/16" or there abouts.











It seemed like the smaller the diameter of the bit, the wider the chisel gets.  I followed the procedure the same for all but the smaller ones didn't come out to well.  Maybe smaller bits have a thicker web for added stiffness?


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## pontiac428 (Mar 3, 2020)

Hmmm, I still think your clocking is off a bit.  I removed the flute guide from my jig because it wasn't a one-size-fits-all solution.  Instead, I eyeball flute alignment off of the wheel and make corrections based on "reading" the point.  What angle are you grinding your points to?  Might be worth trying some flatter angles and seeing how it goes.


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## Weldo (Mar 3, 2020)

So if I understand, the exact point in the inward travel where the drill contacts the grinding surface must be perfectly vertical.  Is that right?

As you feed in toward the grinding surface, with each swing of the jig, the cutting edge will migrate slightly off of vertical, so do you have to reposition it every swipe or two?


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## pontiac428 (Mar 3, 2020)

Weldo said:


> So if I understand, the exact point in the inward travel where the drill contacts the grinding surface must be perfectly vertical.  Is that right?


I'd have to see your jig in action to say for sure.  My jig is oriented differently even though it provides the same action.  In my case, at least with the stickout I've chosen, is 15 degrees off vertical, but that won't have any bearing on your setup.



Weldo said:


> As you feed in toward the grinding surface, with each swing of the jig, the cutting edge will migrate slightly off of vertical, so do you have to reposition it every swipe or two?


YES, this is the case with my jig.  As I grind, the ground tip loses phase with the flutes, so I re-clock after roughing.  Your infeed may rotate the bit for you as the flute follows the indexing finger.  I think this is how it was meant to work, but with my setup that rotation was not very precise.  So I removed the indexing finger and I made a scribe line on my jig for reference.  Now I just align the cutting edge to my mark and no longer feel the need for the indexing finger.

Now I've got to go grind some bits so I can explain it better.  Might need to dull some first.


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## Weldo (Mar 3, 2020)

Haha, dulling bits is easy!  Sharpeneing is another matter!

Thanks for the insights.  I'll try removing the flute index and grinding a few drills with the cutting edge set each way from vertical.


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## Weldo (Mar 3, 2020)

Just did some more grinding.

Here's a pic of how my jig mounts.  When I mention clockwise (CW) or counter clockwise (CCW) it's from my perspective standing behind the jig.  Thus a CW rotation rolls the top part of the bit facing the ceiling towards my right hand side.  Just to clarify.







I did an experiment by grinding a few similar size drills in various orientations.  One with the cutting edge straight vertical, or plumb if you like.  One with the cutting edge rolled CW and one with the cutting edge rolled CCW.  Results follow!

First up was the bit rolled CW.  The cutting edge lines up with the red mark, roughly.






Here's the relief from that same bit.  It's a little steep.






And a shot of the chisel from that same bit.  The angle's not quite right.







Next was the drill bit with the cutting edge vertical or plumb.






Here's the relief from that same bit.  Looks pretty good.






And the chisel from that same bit.  The angle looks right to me.






And also a comparison of that same bit next to a factory grind.  Factory is on the right side.  The angles are pretty close to the same.






Finally is the bit with the cutting edge rotated CCW from vertical.  The cutting edge lines up with the black mark.






Here's the relief from that bit.  It's completely negative and unusable.






And the chisel tip from that bit is going the wrong way.






Lastly I took a shot of all three bits side by side to compare relief angles.






I kind of like the relief on the CW one but the chisel is not very good on that one.  To me overall the vertical on looks the best.  Maybe just a few degrees CW off of vertical would be where I settle.

Next I'll try a few different setting from vertical to maybe 10 or 15 degrees CW and see what happens.


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## pontiac428 (Mar 3, 2020)

Nice work with the testing, good photos too.  Makes what you're doing very clear.

It looks like vertical or +CW from vertical is the ticket.  I think the CW one looks good in profile, but the chisel isn't quite right.  Now you know what clocking does and how to counteract it!  

The next thing to try on those larger bits (about 3/8" and up) is to hand grind a little bit of web thinning in.  Harold hall explains decently.  The image below is from Tubal Cain in _Drills, Taps, and Dies_.  There is another book that covers it better; it may have been Moltrecht, I'll have to look around.  This graphic just doesn't give the right detail.


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## pontiac428 (Mar 3, 2020)

Better diagram, but still doesn't quite cover it...


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## Weldo (Mar 3, 2020)

Ah yes!  I think I know what you’re describing.  I’ve seen some bits like that in my “randoms” box.  That fine grinding must be done on the corner of a stone wheel I assume.


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## NCjeeper (Apr 15, 2020)

I posted in the what did you buy today section but I probably should have posted it here. Bought a Sterling drill grinder.  Pretty siked to get one. They look like this for those that don't know. What is nice is that the company is still in business to get parts.


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