Using a Drill Doctor

[VECtor Calls]

  Finally bit the bullet for a big Drill Doctor 750 to work over my drill bits, especially the 3/4" silver and deming's.

So, I know very very little about drill bit sharpening. Just what I have learned on youtube lately.

Well, it seemed 118 degrees is the norm for wood??So, I cut my go to 3/4" bit to 118. Its a lot sharper than what I have been using.

I used it to cut a couple barrels. The good, my holes are very clean. So clean, (welllll crap, I just realized the answer to my question, but I will continue to be sure to get good opinions to go forward) it will cut down on my sanding.

My problem.....the bit is getting very very hot to where I am GOing to have an issue.


So......my duh moment....

I am running this size and angle of bit too fast, huh?!  Before, with the bit angle flatter, it seemed like I could push at this pretty fast speed, and get through the wood pretty quick. Mostly spectraply, hedge, and persimmon I will be cutting.

What kind of speed should I be looking to use with this new to me bit angle. PLEASE don't tell me toooo slow. I can't stand slow. ;)

[Wade@WEBFoot]

Heat builds up in the tool when its not being kicked out with/in the chips and friction on the tool (flutes)

Friction on the tool is unavoidable to a certain degree, but it is controlled with RPM and feed speed which has an affect of time in the cut - less time in the cut - less heat build up.  But I think the bigger factor is getting the heat in the chip, and out of the hole.

Wood is pretty forgiving - but if youre bit is hot enough to burn wood, its also hot enough to affect the heat treat on the drill to some degree. (tempering generally is done between 350 and 550 degrees - and tempering is reducing hardness)

I dont care for 118 degree points... they tend to walk a bit more than 135 degree - and for metal, there is a notable difference in starting without walking and add a split point and the cutting is much better than any 118 Ive used.

You dont say what RPM youre running at.  But if youre over 300-400 RPM thats probably not helping.  And you need to feed at a decent clip, you dont want small dusty chips, you want bigger chips - that will flow out the flutes - that carries a lot of heat out with the chips.

Another thing that just came to mind - if you have a 118, odds are its not a split point...  The web on a 3/4" drill is substantial... and can add "rubbing" to the point of the bit, where its really not cutting.  A 135 split point, I think youll find will be free-er cutting. 

I would guess, based on you saying the surface finish is better, but getting really hot...  that what you are seeing is that the point is not quite ground right (a very typical thing with Drill Drs - ive found you have to be pretty practiced with it to a good grind, and even then, sometimes it just doesnt work out and you have re-setup and regrind) and its actually drilling a touch undersize and the flutes are rubbing as they get down in the bore.  The flutes would burnish the walls, build up heat, and could be why youre getting so much heat.

Honestly, if you want to increase surface finish quality, reduce your sanding, and have a more accurate bore, I would suggest you get a bit that is 1/64 undersized and then use a chucking reamer to bring to size.  One thing... keep in mind, reamers typically run at twice the feed rate and 1/2 the RPM of a drill bit at that size.  Yes it adds a step, and it adds equipment cost.  But in the long run Ive found its more efficient because you spend less time sanding, and have an accurate bore for mandrel fit, and part fits.

But in the end, I would be suspicious of the grind you have on it right now.  I have the 750X and it aggravates me constantly.  A friend of mine has the 500x and it doesnt fit larger bits, but, it always seemed to work much better.  Wish Id have gotten one of those instead or went with something less plastic and more precise.  All in all, ive been pretty disappointed with the Drill Doctor I have....  to the point, I seldom, if ever use it...  Not even sure where it is right now.

Maybe try a regrind - and see what happens, or try the 135 point with a split point (warning if yours is like me, adding a simple split with that thing is not possible... mine turns it in an hour long process that has to be hard on the diamond wheel.

Cheers
Wade

[VECtor Calls]

Good stuff Wade. Thanks for your thoughts.

I need to try my speeds. I guarantee I have it set up to go way too fast. That will be a start.

I worked over two bits with the DD yesterday to the 118 degrees. When I saw it was so much sharper of an angle than what I was used to, I should have quit with one and asked then.

I am not very picky on my hole size at all, but its nice for it to be smooth. I compensate for hole size differences by making my insert fit to that barrel, and by using different o-rings (13,14,906,907).

I will be sure to think about the type of chips I have coming out of there to get my speed down correctly.

The DD did put very nice and even split points on the bits for me. They were split point before too.

I markered the points before sharpening to be sure I was getting to where I needed to be. For sure, doing a 3/4" bit takes a while.

If my feed speed doesn't work, I will do a flatter angle on some other bits til I get things where I need them.

Thanks again for your thoughts Wade.

[Wade@WEBFoot]

I am not very picky on my hole size at all, but its nice for it to be smooth. I compensate for hole size differences by making my insert fit to that barrel, and by using different o-rings (13,14,906,907).

That would drive me nuts... okya, yeah, I already am...  maybe it would drive me sane :D   I guess Im just too anal.  I like parts that interchange with one another - I start getting fidgity over a few thou these days...  Not to mention having to try and get a customer to measure an oring so I can send them the right ones when they need them or send the call to me, etc...

Life got so much easier for me back when I started learning about tolerances and measuring.  Things just seemed to go together better, work better, much more repeatable, and things felt much more efficient.  But thats just me.  And Im weird :P

To each their own.  If it works for you and doesnt make you batty... then all is well :D

Wade

 

[VECtor Calls]

Been doing it that way for 10 years, because that is the way I enjoy my time on the lathe. Getting too exact and too technical kills the fun of it for me.  When lathe time isn't relaxing to me, I quit and go do something else.

[Wade@WEBFoot]

Completely understand that!

The accuracy is almost a motivator for me... a challenge so to speak.  But like I said earlier, Im a bit weird. :P
Ive been told Im too anal about things... from some pretty anal folks... Im probably a bit OCD 

Wade

[Aaron at Wingerts Woodworks]

I don't have anything positive to add when someone brings up Drill Doctors.  I bought one a year or so back and gave it a whirl.  Then I tried again, and again and again.  I watched videos, I read articles, I followed the directions.  It did a great job for a guy that wants to sharpen granddad's old drill bits to bore holes in 2x4's, but was way too inaccurate to make me happy.  Or maybe I was too inaccurate with it, or a combination of both.  Boxed it back up and took it back to the store for a refund.  "Why are you returning it" she asked...."Because it sucks." 

I sent off my bag of dull bits to Boggs Tool Sharpening and haven't looked back.  That whole big bag of bits came back to me perfectly and precisely sharpened for something like $22. 

[VECtor Calls]

No doubt using Boggs' services has been high on my list of options.

[Wade@WEBFoot]

Im with Aaron, other than mine was a present, so I couldnt take it back.  But had I bought it, Id have taken it back too.

Im not 100% convinced that their instructions are good, or right.  I remembered last night, I have had occasional success with it, playing around with setting the bit in the collet but I cant for the life of me remember what I did or how.  I just know that it was not how the instructions said to do it - but made sense to me, based on the grind I was getting with using the directions.  (If I remember right, I was getting poor cutting, took lots of force to get it to enter wood, let alone cut.

Kind of a bummer, as I had such high hopes when I got the thin for Christmas 7-8 years ago.

I do the same as Aaron presently, unless its an emergency.  Send em out and have them ground, and have them put 135 degree split points on if they didnt have it originally.

I may have to try Boggs, sounds like they do good and have good prices.
Wade

[Aaron at Wingerts Woodworks]

Not to de-rail the thread, but one positive thing about Boggs is that my bits came back sharpened and there was an old school carbon paper invoice in the box.  So they did the work without being paid first.  I mailed a check as requested on the invoice...Again, old school.  I love doing business with people that trust me without even knowing me.  Not that it makes a difference, it just gives me a warm fuzzy.