1153 forum posts
I've been having a bit of a play this afternoon as the weather wasn't up to much.
Doubletop-Pete commented, in the above thread, that he felt that his Sealey was taking off too much metal; so was mine out of the box, albeit a second hand box.
Sliding the wheel towards the motor, will reduce the depth of cut on the primary grind, as it's a tapered wheel.
As you can see from my efforts, I've not quite got it right yet, but even 1/2" bits ground like this, will start off without a pilot hole or centre pop, though I accept the latter's bad practice.
The whole project took rather longer than planned
I sharpened several 1/2" bits using;
A Sealey SMS2008,
A brand new genuine Picador jig; Note that the Picador jig has the vertical pivot, and in theory at least, should work OK out of the box. Drill bit orientation is set by a movable detent on the flute to be ground.
A Reliance No.2 (which needs the bit cutting edge setting by eye). On this one it's recommended to use a projection of three times the drill diameter, so in this case 1 1/2"
I don't claim to be any expert at drill sharpening, but am generally considered reasonably dexterous. I'm sure many on here get perfect results freehand; I know can't
Left to Right, Picador, Sealey Split Point, Sealey Plain Grind, Reliance, New Unknown Make, New Unknown Make Four Facet, and lastly a New Presto 7/16" ( I didn't have a new 1/2" one).
The middle one, ground on the Reliance, was an older Morse tapered one which doesn't look to have had the flutes ground very well from new, hence the odd side view of the relief.
Edited By peak4 on 26/12/2018 17:19:39
|Clive Foster||26/12/2018 17:46:33|
|2317 forum posts|
I also did the "take out the pivot play" thing on a Picador. Discovered that the darn thing worked better with things "as delivered" slack. With the play taken out there isn't quite enough clearance angle at the a back of the flute with larger drills. From memory the effect starts to bite around 3/8" - 7/16". 1/2" drill ended up really sharp on the edge but barely, if at all, cut once fully engaged due to the back of the flute rubbing. Poor thing got a 5 years + stay in the box after that before I decided to give it another go following the instructions rather than improving things. Sometimes the maker does know better and sometimes crude works where precise doesn't.
Essential to make arrangements to accurately and easily adjust the distance between drill jig base and grinding wheel without things twisting and sliding every which way. Mine sits on a scrap of 1/4 plate bolted to the bench with 10 gauge side-plates to keep the jig straight. Wort thing then is getting the projection and angle of twist right. That darn location finger is rather un-useful. Mine gets done more or less by eye with the finger as a reference rather than a stop. I found a narrow, 1/2" or so, cup wheel more reliable than just using the side of a normal wheel.
When it comes to drill setting and location the cheap plastic, but rather decently performing, one in the original Plasplugs multiple sharpener set is the best I've seen. Positive stop for the projection with a sliding Vee gauge to set the angle of twist. "Grip the drill gently in the Vee holder and lightly push it forwards against the stop then turn until gauge is at it's lower point. Then tighten up the drill holder so that it is firmly held." Drill holder fits in the grinder proper both ways up so none of this business of trying to set the second edge exactly 180° to the first. Just grind one side, flip the whole darn thing and do t'other one. Genius. Why aren't they all made that way. Pity flexi plastic construction and trying to make the thing for thruppence three-farthing when fourpence ha-penny would have been a better budget makes getting best results a minor art.
In the process of making the missing bits for my "wallet came out smoking" Clarkson drill sharpener attachment right now. 3 years marinating in t'cupboard is about par. Be interesting to see how well the professional option works.
432 forum posts
Great thread. I'm going to have a play with my Sealey 2008 clone today. The realisation that the ginding wheel position was adjustable and would affect the depth of cut is the basis of my investigation . I have an idea of an approach to doing the basic setup without making it hit and miss. I'll see it there is a way of ensuring the split point still works. It may be a case of the best compromise position of the wheel to accomodate both.
|Henry Brown||12/04/2019 19:38:05|
254 forum posts
Very interesting, following with interest as I'm in the market for something to do a better job than I do at present...
|Dave Halford||12/04/2019 20:58:28|
|869 forum posts|
The depth of cut on the Sealey and the like is set by how far the drill sticks out of the holder, all you need to do is stick something on the metal pad, like layers of sticky tape for eample no need to mess with the wheel position.
BTW you can buy new wheels for them.
|Clive Foster||12/08/2020 22:13:21|
|2317 forum posts|
As requested shifting Clarkson drill sharpener discussions from Dereks Cup Wheel thread of 12/08/2020.
Starting at the beginning the Clarkson system uses a 6 jaw chuck with long sloped jaws to hold any drill from about 2.5 mm to 16 mm, 1/8" to 5/8" diameter. The chuck jaws are about 2 1/2" total length so as to grip the spiral lands in a stable manner.
Setting up merely requires the cutting edge on the wheel side to be set level with its outside end, i.e the full diameter of the drill, 1/2" proud of the chuck jaws. The instructions say that there is a setting gauge to make this easier. I've never seen one or a picture of one. The chuck mounting shaft is free to rotate in its carrier casting with an indexing device at the other end to select the second edge. Obviously it is bored out to give the drill shank somewhere to go. The carrier casting pivots up and down on a shaft fixed into the main support post. The pivot shaft is set at an angle to the chuck carrying post so that swinging the cutting edge upwards grinds the correct clearance on the drill.
Assuming the chuck carrier shaft is set to as to give the correct point angle the only requirements for a correctly backed off drill are :-
1) the pivot shaft and chuck carrier shaft be at the correct relative angles
2) the drill cutting edge is the correct distance from the intersection of the shaft centre lines.
So far as I can see the shaft centre lines are in the same plane which is perpendicular to the cup wheel face.
Hence given the shaft angles it should be relatively easy to replicate the sharpening geometry with a simple post support. Some means of applying controlled small cuts is essential. Already present if fitted to a T&C grinder. Otherwise some sort of screw or micrometer controlled slide will be needed.
The actual Clarkson implementation is angularily more complex to incorporate tap lead grinding.
Photos show the device moved clear of the grinding wheel so a drill can be put in the chuck. Grubby wheel is still flat so not due for dressing. Yet!
Whole thing on Clarkson
Top View showing indexing device, shaft angles and spring loaded pin that sets chuck position
The calibrated cam-plate device next to the pivoting handle isn't used for drill sharpening.
1153 forum posts
Thanks for that Clive, the top view makes things a bit clearer.
I've never seen their drill sharpening gizmo in real life, nor spotted one at a justifiable price for hobby use.
|Clive Foster||12/08/2020 23:21:47|
|2317 forum posts|
Not quite. The grinder table angle is irrelevant. All that matters is that the drill is at the right angle to the grinding wheel to give the desired point angle.
The factory Clarkson set up has the table at 15° for drill sharpening because that makes calibration easier for the tap grinding function which has the table at a different angle anyway.
1153 forum posts
I sort of meant that, as I thought the base of the attachment was keyed to the slot in the table, with the photo showing the casting edge at apparently right angles.
3809 forum posts
An interesting subject where no system has ever really become the definitive route for the hobby market
I had one of those picador type things but it was too fiddly for me
Used a great one from B+Q years ago which was fabulous for the 48 hours that the grinding stone lasted but the spare stones were about a fiver for two
The multisharp uses the same sort of simple stone system, the big problem is you put a gutter into the stone really fast once you start doing a few drills
Lidl cheapo ones for a fiver tend to have two spare cup stones
Grinding drills by hand helps to keep your eye in for when you need to grind a special cutting tool
It's a real whatever-works-for-you thing where hand sharpening gives the least hassle for an acceptable return
Edited By Ady1 on 13/08/2020 05:53:32
|20 forum posts|
CLARKSON SETTING GAUGE.
poor photo attached, gauge is 1/16" thick, legend reads "STANDARD CLEARANCE" with + to lhs of the line and - to rhs.
|1645 forum posts|
The lands look too wide to me on the Unknown Make New(ish) Four Facet Commercially Ground; pictured above, also I understood the grind lines between clearance angles should be parallel on a correctly ground 4 facet drill.
|Howard Lewis||13/08/2020 13:10:27|
|3536 forum posts|
From the sublime to the Gor Blimey,
Plasplugs, via Picador to a Clarkson!
If you can access a cutter grinder, the four facet method is by far the best method of drill sharpening.
Effectively an end mill ground at an angle.
Very effective, and reputed to be self centering, and so no need for centre drills or spotting drills.
|Clive Foster||13/08/2020 15:20:11|
|2317 forum posts|
Great picture of the setting gauge. Many thanks.
All drawn up and ready to make next time I'm on t'mill.
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.