That's a good point. This doesn't have to be an all or nothing deal. Some shades of grey makes sense.
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Tool Vevor Drill Bit Sharpener
- Thread starter canuck750
- Start date
Tool
That's a good point. This doesn't have to be an all or nothing deal. Some shades of grey makes sense.
Another good point. But for me it isn't really a big deal as I have a full set of imperial ER20 collets I can use.
I was really only pointing out the uneven way that the 6mm collet closed down. A 5C can't do that. I have 5C, ER11, ER20, and ER32. So I have no horse in the race. But this observation suggests that 5C collets might be a better choice when concentricity really matters. I plan to do some more testing to see how this shakes out.
Edit - holy crap! Not REALLY ER20. Actually inverse ER20.
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You must be kidding! Does that mean I can't use my imperial ER collets?
I can't believe I missed that!
This might have many implications......
I assumed that you need something like https://www.lathes.co.uk/christen-drill-grinders/ for smaller drills.
TorontoBuilder
Sapientia et Doctrina Stabilitas
The <1/8" bits I have are crap right out of the box and need sharpening. I guess just buying better bits
TorontoBuilder
Sapientia et Doctrina Stabilitas
You can use normal ER collets.
But you can get inverse clamping collets to increase the range... the 2mm collet and the 14mm collet, and a special ER20 chuck and 15mm collet.
trlvn
Ultra Member
General drill sharpening jig with 1/16" drill clamped:
The flute to be sharpened is not vertically aligned like it needs to be...but that is because my magnifier was at the far end of the shop! Note that I removed the flute stop as it wasn't going to help with a drill this small and would be in the way when sharpening.
Not tested but it looks like it would work. Might possibly grind away a bit of the front of the jig but that wouldn't actually hurt anything. My only concern would be that the clearance angle _might_ be excessive leading to a weak cutting edge.
TBH, the only time I grind very small drills is when I don't have a sharp alternative. I have one of those multi-packs of the standard fractional drills up to 1/4". If I had problems with a small size number or metric drill--and didn't want to wait until I could buy a fresh drill--then I'd try sharpening something small. So far that hasn't happened so I don't know what really happens to the clearance angles.
Craig
(I use my General jig with a 1" belt sander. 120 grit blue zirconia belts work great for sharpening most drills. For small drills I'd probably use a 400 or 800 grit mylar belt. The General jig easily handles drills up to 3/4" diameter.)
I made a rudimentary drill faceting tray/stop for my Franken-TCG which uses a square 5C collet block. I'll post pics once I digest my photo dump. Anyways what I hadn't appreciated is gripping a drill is not quite the same as gripping normal cylindrical objects. The drill land is the only contact area & of course its a relatively small percent of the circumference. If the 5C is not sized very close to the drill size, loosening can be a problem. I think because the 5C leaves are bending inward & the clamping is biased towards the collet nose representing an even smaller proportion of grip to its holding ID. I also have an ER-16 collet jig for a different purpose, it grips drills better for the same tightening torque because its radially contracting. Jobber drills actually have a teen amount of taper but somehow the collets manage. Anyway, sounds crude but I just wrap 2 winds of almost any kind of tape on the lands. This not only protects the edge from collet clamping but gives the collet kind of a gasket effect to grip properly. Tape is amazingly uniform in thickness. Much more accurate than some of the drills I'm playing with. LOL
Attachments
What? I don't understand. Clamping on the narrow end? What narrow end?
Ya, whacky. Just imagine sticking a drill bit into an ER collet business end first. Stick it all the way in till the butt of the drill is flush with the collet face. Now flip the collet around end for end and sharpen the business end of the drill.
Easier and faster to explain other ways, but it's new years day and I feel like being a crap disturber.
Now I know why I noticed the 6mm collet centering issue.
Thanks, pretty much what I was visualizing. So is the design intent the collet nose area is slimmer than conventional collet orientation & that helps with how it inserts or moves within the grinding fixture?
Kind of neat actually. Because ER collapse accordion style by axial force & the contact area is entirely on the ID, never occurred to me they could be flipped.
Kind of neat actually. Because ER collapse accordion style by axial force & the contact area is entirely on the ID, never occurred to me they could be flipped.
Me either. I even did it and didn't notice! Dooo.....
@TorontoBuilder pointed it out.
Get this! For this special backward configuration, they make ER25 collets all the way up to 20mm! So I could even sharpen 3/4 drills on this thing!
Gunna sharpen all my junk drill bits.
TorontoBuilder
Sapientia et Doctrina Stabilitas
I tell yeah, based on the chinese sites and their available info it was hard to see how they got their claimed grinding ranges.
But at the very end of Stefan's duo grinding video he says the collet faces look funny, because the collet clamping is inverted and the sizing bore is located in the skinny end.
For instance, look at this 2mm collet:
look at the pointy end... and the projection
Look at the normal sizing diameter... that's not round, and that's not 2mm
I'm trying to secure the special 20mm ER25 collets, and plan to order the 2mm ER20 collet as well as the ER25 collet chuck.
TorontoBuilder
Sapientia et Doctrina Stabilitas
Update on the grinding capacity of the MR-13A/B/D machines which according to the manufacturer is 3-13mm, or sometimes 3-15mm.
ICYMI the D machine is the duo. They're easy to acquire from the manufacturer off of aliexpress for the low low cost of $557CAD plus shipping charge of $175CAD, or about $805CAD with tax upon arrival since this wont slip past customs. Or follow this thread
and build your own from a 13A or B machine for less than $100
The grinding capacity can be increased on these machines to provide a range from 1mm thru 15mm using only the ER20 collet chuck by purchasing accessory collets.
1 and 2mm ER20 collets from aliexpress, but you can find the same sizes in ER25 collets too as well as 14 thru 16mm.
You can find ER20 collets in .5mm sizes as a set here, but a little pricy for just 4 collets
Thanks to @Susquatch who found ER25 collets in sizes 17, 18, 19, and 20mm from this vendor on aliexpress.
The ER25 collet chuck that fits these machines can be purchased here
These purchases will result in a full range from 1mm thru 20mm drill bits.
I purchased 1mm and 2mm ER20 collets, the Er25 collet chuck and 13 - 20mm collets for $130
psst @Susquatch see embedded links if you haven't already found all of these
ICYMI the D machine is the duo. They're easy to acquire from the manufacturer off of aliexpress for the low low cost of $557CAD plus shipping charge of $175CAD, or about $805CAD with tax upon arrival since this wont slip past customs. Or follow this thread
I've worked out the mod for a duo grinder that combines the features of the Vevor 13A and 13B and I'd like to propose a group project for all members who are interested.
Below is the 13A innards (motor mount plate and the pivot) for the split point grinding.
Below are the 13B innards (motor mount plate and the pivot for web thinning.
I believed that the duo machines had to have their pivots moved to the middle of the motor mounting plate.
The motom appears to confirm that the web thinning pivot has been relocated to the mid point of the motor mount. It is...
Below is the 13A innards (motor mount plate and the pivot) for the split point grinding.
Below are the 13B innards (motor mount plate and the pivot for web thinning.
I believed that the duo machines had to have their pivots moved to the middle of the motor mounting plate.
The motom appears to confirm that the web thinning pivot has been relocated to the mid point of the motor mount. It is...
and build your own from a 13A or B machine for less than $100
The grinding capacity can be increased on these machines to provide a range from 1mm thru 15mm using only the ER20 collet chuck by purchasing accessory collets.
1 and 2mm ER20 collets from aliexpress, but you can find the same sizes in ER25 collets too as well as 14 thru 16mm.
You can find ER20 collets in .5mm sizes as a set here, but a little pricy for just 4 collets
Thanks to @Susquatch who found ER25 collets in sizes 17, 18, 19, and 20mm from this vendor on aliexpress.
The ER25 collet chuck that fits these machines can be purchased here
These purchases will result in a full range from 1mm thru 20mm drill bits.
I purchased 1mm and 2mm ER20 collets, the Er25 collet chuck and 13 - 20mm collets for $130
psst @Susquatch see embedded links if you haven't already found all of these
Yes, you sent me a few earlier and I found the rest. I just have not figured out how to stop the vendor from gouging me on shipping or I would have already ordered.
