I'm wondering about getting the DBS-22 sometime soon. I have quite a large collection of spot drills and quite a lot of them are blunt now, so I'd love to be able to sharpen them. Can the DBS-22 sharpen this sort of thing?
Example of the type of drill I'm talking about: https://www.scribd.com/document/276985270/Nc-Spot-Drills
Welcome to the forum, Dr.Al.
Good question. I don't have any spot drills, so I forwarded your post to Tormek Support. Unfortunately, they are on vacation until July 31, so response time will probably be slower. We do have several members who are machinists. Hopefully they will reply.
Ken
I see no reason why that type of drill could not be sharpened. The flutes are straight and it looks like there is just the primary facet and a relief. I think it will be important to get the point well centered as accurate locating is the "point" of this type of drill.
I don't have any drills like that and have not used them before. I use centerdrills with the two stepped flutes. They are on the small side, typically and I've not tried sharpening the points on them, but they do become dull.
Rick
Quote from: RickKrung on July 25, 2023, 03:47:19 PMI see no reason why that type of drill could not be sharpened. The flutes are straight and it looks like there is just the primary facet and a relief. I think it will be important to get the point well centered as accurate locating is the "point" of this type of drill.
I agree that getting a well centred point is essential for these drills. I've shied away from trying to (hand) sharpen them as I don't think I'd be able to maintain the centre accuracy. If the DBS-22 can do it then that would definitely tempt me to get one.
Quote from: RickKrung on July 25, 2023, 03:47:19 PMI don't have any drills like that and have not used them before. I use centerdrills with the two stepped flutes. They are on the small side, typically and I've not tried sharpening the points on them, but they do become dull.
I also used to use centre drills for this application. Then I discovered spot drills and I've never gone back (except for drilling centres in the lathe, obviously). The spot drills are even better at starting in the right point than centre drills and they are
a lot more robust.
As a side benefit, they're sharpened at 90°, so I sometimes use an oversize one to start a hole, then drill the through hole with a smaller drill bit - the result is perfectly aligned countersunk hole in two operations. Of course that only works if you're using sensible metric fasteners with a 90° countersink included angle :)
Quote from: Dr.Al on July 25, 2023, 04:04:35 PM...snip...
except for drilling centres in the lathe, obviously). The spot drills are even better at starting in the right point than centre drills and they are a lot more robust.
...snip...
If the latter statement above is true, why would you not also use them for drilling centers on a lathe?
Rick
Quote from: RickKrung on July 26, 2023, 02:46:17 PMQuote from: Dr.Al on July 25, 2023, 04:04:35 PM...snip...
except for drilling centres in the lathe, obviously). The spot drills are even better at starting in the right point than centre drills and they are a lot more robust.
...snip...
If the latter statement above is true, why would you not also use them for drilling centers on a lathe?
Rick
Because the point is 90°, whereas centres are 60°. Also, the little nib on a centre drill gives oil somewhere to go when you push the dead centre into the hole made by the centre drill.
Quote from: Dr.Al on July 25, 2023, 10:13:43 AMI'm wondering about getting the DBS-22 sometime soon. I have quite a large collection of spot drills and quite a lot of them are blunt now, so I'd love to be able to sharpen them. Can the DBS-22 sharpen this sort of thing?
Example of the type of drill I'm talking about: https://www.scribd.com/document/276985270/Nc-Spot-Drills
If you want to send me one, I will try to sharpen it on my DBS-22 and send it back to you. If interested, PM me.
Quote from: RichColvin on July 28, 2023, 04:10:23 AMQuote from: Dr.Al on July 25, 2023, 10:13:43 AMI'm wondering about getting the DBS-22 sometime soon. I have quite a large collection of spot drills and quite a lot of them are blunt now, so I'd love to be able to sharpen them. Can the DBS-22 sharpen this sort of thing?
Example of the type of drill I'm talking about: https://www.scribd.com/document/276985270/Nc-Spot-Drills
If you want to send me one, I will try to sharpen it on my DBS-22 and send it back to you. If interested, PM me.
Thanks for the very kind offer Rich, but your profile suggests you live in Ohio & I suspect that sending a drill bit across the atlantic ocean & back again will cost too much to be worth the hassle.
Quote from: Dr.Al on July 25, 2023, 04:04:35 PM...
As a side benefit, they're sharpened at 90°
...
The DBS-22 manual (https://tormek.com/download/18.681cbd68182e94c066a21e2d/1688042189465/InstructionDBS-22%20Drill%20Bit%20Sharpening%20Attachment.pdf) on page 4 says:
QuoteCentering drills usually have a 90° point angle.
Might be a clue that it will? ???
Quote from: cbwx34 on July 28, 2023, 03:37:43 PMQuote from: Dr.Al on July 25, 2023, 04:04:35 PM...
As a side benefit, they're sharpened at 90°
...
The DBS-22 manual (https://tormek.com/download/18.681cbd68182e94c066a21e2d/1688042189465/InstructionDBS-22%20Drill%20Bit%20Sharpening%20Attachment.pdf) on page 4 says:
QuoteCentering drills usually have a 90° point angle.
Might be a clue that it will? ???
Sounds promising, unless it means centre drills (for drilling centres in the lathe). These have a point (I'm not sure of the angle; I can check when I'm next in the workshop) and a short narrow section. They then have a 60° larger section for cutting the centre itself.
Having said all that, centre drills are very short, so I'd be surprised if you can hold them in the jig. Also, I tend to break the fragile tip long before they go blunt, so I probably won't ever need to sharpen a centre drill ;D
For that matter, spot drills are quite short too: perhaps that's a limiting factor regardless of geometry? My smallest spot drills (3 mm diameter) are about 50 millimetres long I think; when you set the drill protrusion with the stop on the DBS-22, how much sticks out of the clamp?
Just in from support:
"Hi Ken.
You need the protrusion and at least 1/3 of the length inside the drill holder. 2-2,5" in length is minimum. Do you know the length of the drill bits?
Have a nice day."
Ken
Quote from: Ken S on July 28, 2023, 09:01:27 PMJust in from support:
"Hi Ken.
You need the protrusion and at least 1/3 of the length inside the drill holder. 2-2,5" in length is minimum. Do you know the length of the drill bits?
Have a nice day."
Ken
The shortest drill bit is 50 mm (so about 2"). The bigger sizes are a bit longer.
This is my little collection of spot drills that I'd love to be able to sharpen:
20230729_101134 - Copy.jpg
I probably use them more than any other drill bits as most holes are started with these bits.
This is the best photo I could take (of a 12 mm spot drill) showing the tip geometry:
20230729_101558 - Copy.jpg
Sorry it's blurry: they're hard to photograph!
This photo shows the lengths of all the spot drills (3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm and 12 mm diameter):
20230729_102429 - Copy.jpg
The grid on the paper is 5 mm squares.
I really see no reason why the DBS-22 would not work unless they are made from some metal composite which is extraordinarily hard to grind.
Quote from: RichColvin on July 29, 2023, 04:39:12 PMI really see no reason why the DBS-22 would not work unless they are made from some metal composite which is extraordinarily hard to grind.
They're HSS, so I'm not concerned about the Tormek grinding them.
The stuff I'd seen on the DBS-22 seemed very focused on conventional twist drills & I wasn't sure whether any difference in geometry would be significant (as you can probably tell, I don't know much about drill tip shapes).
Quote from: Dr.Al on July 28, 2023, 04:43:49 PM...snip...
Having said all that, centre drills are very short, so I'd be surprised if you can hold them in the jig. Also, I tend to break the fragile tip long before they go blunt, so I probably won't ever need to sharpen a centre drill ;D
For that matter, spot drills are quite short too: perhaps that's a limiting factor regardless of geometry? My smallest spot drills (3 mm diameter) are about 50 millimetres long I think; when you set the drill protrusion with the stop on the DBS-22, how much sticks out of the clamp?
I have not followed through in the discussion from a while back about the use of pin vises for holding smaller diameter drill bits (https://forum.tormek.com/index.php/topic,3757.msg), but it seems to me that pin vises would be an excellent solution for holding center drills and spot drills for sharpening with the Tormek. I still need to turn the hex handles round on the Starrett pin vise, but maybe I'll get to it one of these days.
Rick
I have come to the understanding that spot drills and center drills are the machinist´s choice for a lathe or any other device (like a mill) that has a very tight grip on the tool, plus an equally well fastened work piece.
They are a bad choice for the layman´s cheap drill press, let alone hand operated units, because they are not ground to any particularly special shape that would foster a good hole start.
As I (hopefully) layed out on my recent contribution ("Musings...") the hobbyist is far better off with a small (store-bought) drill with some form of web thinning (split point), followed by the final drill with practically any grind you like.
Since you seem to belong to the prior clientel and thus seem determined, the answer is: no, you cannot sharpen them on the Tormek if they are small.
Gadgetbuilder (https://gadgetbuilder.com/DrillSharp.html) talks a lot about this subject. He advises against center drills for certain reasons and recommends sharpening spot drills to a 4F shape. He also explains several reasons to not sharpen them to the 90° or whatever acute angle they commonly have.
That all said, bear in mind that he comes from the lathe corner. I found that a short stubby drill I had sharpenend to those specs bears no advantage on a drill press, however a 4 mm (store bought) drill with split point was far superior for starting holes.
Drilling on a lathe is not the same as drilling on a drill press or manually.