A 4 Facet Drill Bit Grinder DIY Style Part 6

[@Xpzd]

Now that’s a quality drill sharpener! For anyone suggesting a drill doctor has never used or owned a drill doctor. I own both the normal and a 750x and I’d rather buy a new bit then try to sharpen one.

[@howardosborne8647]

I've owned a 750 model and it has spent almost all of its life in the box because it is a bloody hopeless contraption🤣

[@Watchyn_Yarwood]

@@howardosborne8647 I bought one, used it about 6 months and gave it away to my neighbor.

[@rak6080]

I own and use a drill doctor. Most of the time it works great. There are times that for some reason it doesn't, but it is usually me not setting the drill bit correctly. Funny that the reviews of them either say they work great or they don't work well. For me, well worth having it.

[@MattysWorkshop]

Gday Preso, I can agree it’s much more enjoyable building the tool rather then jamming ya hand in the wallet and buying it, once you get completely used to the machine it’s going to be quite quick to sharpen a drill, great job mate, cheers

[@Preso58]

Thanks Matty. Making something that works is sublime. Even if it doesn't work so well, you have still learned something. Regards, Mark

[@theromihs]

Great project Preso. I have a suggestion on how you could reduce the setup time and simplify the process. You can incorporate the drill bit length into the drill edge alignment jig by offsetting the dowel pin holes in the aluminium plate to the correct distance from the Perspex screen for the required length for either operation. (ahhhh scratch that, one needs to remove the collet to tighten the nut anyway...)

[@stevecarlisle3323]

Another Great video. Here in Canada all the high Quality drill bit sets, and individual, are split point. As for just buying a Drill doctor, most all of those sold, are sitting on a shelf, or have already been tossed in the garbage.

[@MASI_forging]

Many thanks for the series Mark. You did very well. I love all your video.

[@rlsimpso]

I am very tempted to build one of these. To comment on the Drill Doctor, I have the 500 and the 750. I have used the smaller one enough I just had the get a second chuck. They work well, but are very slow on larger drills. and the split point function is not the best. Your grinder is much faster and that is well worth it. I am interested to see the difference the 200 grit wheel makes. Thanks for sharing.

[@Preso58]

I sharpened a couple of drill bits yesterday and I have the cycle down to about 5 minutes per drill bit and that includes backing off the heel with the split point accessory. It takes a bit longer to grind a damaged or poorly ground bit initially but once all my drill stock has the 4 or 6 facet grind it will be a bit quicker. I am going to make a couple of sector plates to increase the secondary relief angle. It's a bit of a nuisance to have to back off the heel. If I can get the secondary relief correct it may not be necessary. Regards, Mark

[@garychaplin9861]

A great series Mark, I really appreciate the detail you provide of the use, difficulties and improvements you have made to the grinder. I hope you can do an update when the new wheel arrives and any further changes or improvements that you make. All the best.

[@Preso58]

Gary, I did receive the new wheel but it seems to be poorly balanced compared to the 80 grit wheel. I have tried tapping it in to get it truly concentric and I have made a new clamping washer with a shoulder that fits inside the bore of the wheel. They are also quite heavy. The diamond wheels I have used have aluminium bodies but the CBN wheels are steel. I guess it is so they can plate the surface to hold the CBN grit in place. I am sure I can improve the setup but for now it's hard to compare how well it grinds until I get the machine back together again. Regards, Mark

[@garychaplin9861]

@@Preso58 It sounds like you need to make a balancer. I smell another project hatching.

[@traindriverluke]

Great stuff Mark, I've enjoyed watching the build series on this. Great remark on why your building on and not buying a product. The hobby is about the building journey and learning sometimes over the end product.

[@grahamlucas6033]

Challenging project Mark, nice result and a tool that will last a long long time well done.

[@RobertBrown-lf8yq]

Really nice bit of kit Mark 👍 Looking forward to see the 200 grit wheel in action Regards Robert

[@Preso58]

I fitted the new 200 grit wheel earlier in the week. It seems to be poorly balanced and they are quite heavy with the body being made of some sort of plated steel. I need to do a bit of work to improve the setup but for now it does make a finer cutting edge on the drill bits I have sharpened with it. Regards, Mark

[@DonDegidio]

Hi Preso, Enjoyed the entire series. Great when a project is finished and can be put to use. Looking forward to seeing it after it's prettified and to your next project. You and the family stay safe.

[@kenwood8665]

Absolutely brilliant video

[@thehobbymachinistnz]

That is a great drill bit sharpener Mark. When I eventually come to visit I will add an extra day to my itinerary and I will bring all of my drill bits to be sharpened :) Seriously, well done on this project, and it will be interesting to see how the 200 grit wheel goes.

[@Preso58]

We must all have a giant box full of dull or damaged drill bits. I know I have my fair share. Regards, Mark.

[@ianbertenshaw4350]

Nice bit of kit Mark! Even though I have things like a D bit grinder and the Harold Hall grinding jig I still find for most drill bits over 3mm diameter I just sharpen by hand grinding - under 3mm I tend to replace them. I still feel that being able to sharpen drill bits by hand is something that all machinist/ model engineers should strive to achieve along with grinding HSS cutting tools for the lathe - it is part of the learning curve that gives one the basic skills needed - just like learning to use a file properly .

[@Preso58]

Thanks Ian. I can offhand grind bigger diameter bits but it was the small (sub 3mm) bits that I really needed some sort of grinding jig for. I made a drill grinder to the design by David Lammas but it relied on a smallish jacobs chuck to hold the drill bits and after spending ages machining the castings and making all the other parts I found that you cannot grip a twist drill in a small 3 jaw chuck since the jaws are too short to hold the drill on axis. The design required the back of the chuck to be open so you were able to pass the drill bit right through the chuck so you could keep the stickout short. It never worked! The beauty of the ER20 collets is that they hold the drill bit predictably and you can grip any size bit. Regards, Mark

[@michaelmarks8954]

100 pounds of very dull drill bits in various sizes coming your way Thanks ahead of time 😬Enjoyed the kangaroos 🇺🇸🇨🇦🇺🇸

[@Preso58]

Take a number and stand in line! 😁

[@ambisinisterengineering5242]

Split points are great for stainless steel fabrication if there is tolerance and accuracy is not imperative it saves making a work hardened point by using a centre punch for the chisel of the drill to try cut through

[@Preso58]

I didn't realise that you could work harden just by centre punching. I have burned the ends off drill bits on the work hardening grades of stainless by using inconsistent feed rates and speeds though. It's never pretty when it happens! Regards, Mark

[@Steviegtr52]

The whole machine looks great Mark. Like you say if you have the tallent , use it & keep your wallet in your pocket. Regards. Steve.

[@Preso58]

Thanks Steve. I received your new stickers and they will go up on the door in the next video. I must say, they are a big improvement! Regards, Mark

[@roylucas1027]

Thank you. Great series.

[@howder1951]

Great video Mark, makes me jealous as with my drill doctor, the indexing is iffy at best with the smaller bits. Looking forward to the finishing show for this unit, enjoyed the roos, cheers!

[@frankinpattaya]

Well done Mark, great job,, my Tormek DBS-22 Drill Bit Sharpening Attachments takes a fair bit of playing with setting it up as well, it will do from 3 to 22mm (but will do 25) & angles from 90 to 150* with a fair bit of pucker marks at times to start off with, I’ve found the bigger the bit is the easer it is, all takes time and playing with.. Thank you for showing us all the work you have put into this fantastic job. Regards Frank 😊

[@MyLilMule]

I like this project very much. Of course, it'd be "easier" to buy new drill bits or a Drill Doctor, but I don't think you'll get the same level of quality that you'll get with some practice. Nothing frustrates me more than trying to use a tool and the tool doesn't work. Having sharp drill bits that just cut like butter makes the whole process that much more enjoyable. Brilliant job, Preso!

[@Preso58]

Thanks. I am looking forward to being able to sharpen the very small drill bits. I haven't tried it yet but John Moran claims that you can do a single facet grind (just the primary clearance angle) on bits under around 1/8". Regards, Mark

[@russelldold4827]

Looking forward to seeing the difference between the two grits. Nice work, Mark!

[@jimhunt5259]

Nice job. Man there are more step to that thing than a barn dance.. : - )

[@Preso58]

It does seem that way but it take longer to explain it than it does to do it. Regards, Mark

[@jonlorton9604]

Many thanks for this series Mark, this grinder is an answer to many wishes. I've already obtained the drawings and I now have to source a suitable drive motor then get on and build it !

[@calvarybuilders5689]

Your upgrades are perfect! When you mentioned putting the drill fixture back in the same aligning holes on the tip plate, maybe scribe lines on the plate? then deepen the lines and paint them two different colors.

[@Preso58]

John Moran suggested making a "snooze alarm" which is basically a way of blocking one hole with a small cheese head screw so you cannot accidently use that angle. Nearly all my drill bits will be ground with the 118 degree point angle so I may just plug that hole with some sort of fastener. Regards, Mark

[@skypatrol716]

Very nice Mark 👍 a hand made tool is always a joy to use.

[@allengentz7572]

Thanks Mark another great build

[@CraigLYoung]

Thanks for sharing 👍

[@fna-wrightengineering]

Clever bit of kit, Mark! Nice to see it finished, and properly accessorized. A suggestion to counteract the parallax with the alignment jig: you could place another piece of acrylic, a quarter-inch or so in front of (or behind) the original one, with a line scribed at the same height. This way, when the lines are... well, aligned, it means you're looking perfectly end-on to the jig.

[@stejac51]

OR ... alternately you could place a small piece of mirror behind the line which would allow you to accurately align your Mk. 1 Eyeball with the scribed line on the acrylic .....

[@Preso58]

I found it surprising, but the engraved line is a lot thicker than you would imagine and it does tend to obscure the cutting edge of the bit. I worked at a helicopter company doing some work experience and they used a string line and a small mirror to align the two blades on a main rotor. The little mirror was placed under the string line so you just aligned the string and it's reflection to eliminate the parallax error. If that wasn't low tech enough, they also checked the trim of each rotor blade by standing under the rotor with a long stick topped with a piece of chalk. The rotor was powered up and they held the stick under the rotor until the chalk started marking the rotor blade/s. If both blades had an equal thickness of chalk on them, the blades were in trim! I will need to revisit the alignment jig, especially for the smaller bits. Regards, Mark

[@martinconnelly1473]

I don't think it is essential to be aligned perfectly with the centre of the drill. With a larger drill the cutting edge is offset from the drill axis more than with a small drill. The ability to look at the cutting edge from different angles help to view the cutting edge and the line in close proximity. The two cutting edges are offset from a horizontal line through the drill axis by about half the length of the chisel edge, this is easy to see if you look at a large diameter drill.

[@stejac51]

@@Preso58 Mmmm ... your quite right I've been a Heli LAME since '76 ... happily technology has advanced Tracking & Balancing somewhat over the years .... the mirror trick is still valid though and was used back in the day on some analog instrumentation in order to accurise needle readings etc ... Cheers.

[@billawad154]

Loved the series on the build. Managed to get my hands on a motor and spindle and once your CAD drawings are made available I will start the build. Yes I do have a clone d-bit grinder and have sharpened bits on it, but I also share your frustrations during the sharpening process. Excellent work.

[@Preso58]

Thanks for watching. I am just tidying up the drawings and including some notes. They should be ready by the time the next video is released. Regards, Mark

[@mechjack]

Great job!

[@bradleymasson1777]

Sharpening drill bits is a world of its own. I worked in a shop that bought a Drill Doctor; it was fine when new, but got sloppy and useless rather quickly.

[@tonyray91]

I use a digital angle finder - one of the small square ones to set the secondary’s & primary reliefs on my Kennet T& C grinder it’s a lot quicker than stooping to read the graduated scale. Your table doesn’t have a lot of room so a riser block might be needed. I don’t need it but am still tempted to build one.

[@Preso58]

I do have a small digital angle finder. I hadn't thought of using it though🙄 The clearance angles aren't critical though. I guess if you were regrinding a previously sharpened drill bit it would reduce the amount of material you would need to remove if you could set up the angle accurately. Regards, Mark

[@tonyray91]

Yes it does help repeatability, on my setup it’s useful if I have to go back an re grind if I’ve over cooked the primary relief - I’m new to this too.

[@acmemachining]

Great job Mark. Well explained. Thanks

[@Preso58]

Thanks for that Todd. I meant to let you know that I received your stickers. I am waiting for some from Bart Harkema (in the Netherlands) and I will add both yours and Bart's at the same time. We just finished watching a travel series by Griff Rhys Jones where he travels right across Canada. It has reignited our passion for visiting your wonderful country. This time we hope to get to the east coast. Regards, Mark

[@brucewilliams6292]

Great job Preso. Really appreciate you putting this video together. It would be nice to see the plans.

[@Preso58]

I am still working on the drawings. I am hoping that all the revisions will be completed by the time the next video comes out. Regards, Mark

[@brutusyt2842]

That's quite the result, nifty bit of kit! This series helped me understand the geometry and setup of my kaindl drill sharpen jig that came on a grinder (without a manual). Your machine seems to grind a fair bit more accurate than this commercial jig! Best regards from Groningen, the Netherlands.

[@Preso58]

I must say I was surprised at how accurately the facets intersected without having to adjust anything after the secondary relief was ground. I think I got lucky though. The original drawings I received from John Moran were more of a guide than anything else and it took quite a bit of work to get the CAD model accurate. Once you get your head around the importance of having the pivot point for the trunnion co-planar with the face of the wheel, the rest falls into place. I will add your location to my map. The Netherlands is on our bucket list of places to visit. Regards, Mark

[@brutusyt2842]

Making a cad model must be very insightful. Will try my hand at that. If you're ever in the north of the Netherlands you're more than welcome to drop by and enjoy a pint ;-)

[@johnhall8455]

I would change the clearance angle so that it removes the heel problem….it’s the primary angle that’s most important….have a look at Dormer 4 facet grind angles

[@Preso58]

John, as it turns out, the sector plate I was using was incorrectly sized and it wasn't giving the 25 degree angle required for the secondary clearance angle. I have since made a new one but I haven't been able to test it yet since the machine is in pieces while I do all the metal finishing processes on it. I am hoping that the extra couple of degrees will mean that I don't need to back off the heel of the drill bits. Regards, Mark

[@mce1919A4]

Nice work.

[@JesseSchoch]

nice build!

[@joewhitney4097]

The Bit Grinder is coming right along. One thing I saw and wondering about. When you showed the up close of the grind, and the grind was not straight across. Could that be from the fixture moving or flexing? The reason I ask is while watching you grind the bits, it appeared depending what you movement was and where you were applying pressure I could see movement in addition to the process of the machine and or the fixture even though it was very slight. The machine appears to be coming along nicely but wanted to let you know what I thought I was seeing. Love your videos and thanks for sharing.

[@Preso58]

Joe, well spotted. As it turns out, one of the countersunk head screws which holds the collet block onto the collet block foot (base) was protruding slightly which caused the whole collet block to rock on the base. I only spotted it when I began to grind the split point. I made the countersink a bit deeper and now it sits quite solidly on the trunnion. Regards, Mark

[@RB-yq7qv]

Hi Mark. Yes making the tool gives one achievement credit just lowers your bank account

[@marlobreding7402]

Tell Them "It's not the Destination, It's the Journey".

[@Preso58]

That's it exactly! Regards, Mark

[@chrisarmstrong8198]

The split point grind seems to remove a lot more off the drill bit's heel than is actually required for clearance. If the aim is to make the centre part of the large diameter drill bit look like a small diameter drill bit, is there a way to grind just the centre part without taking so much off the heel ?

[@Preso58]

I did actually grind a bit fairly early on that didn't need to have any material taken off the heel. This was before I had made the point splitting accessory. I think the margin for error is very small and the heel of the bit always seems to be a bit high for my liking. You can just nip off the heel by freehand grinding and you don't need to take much off anyway. I must say I have only ground about 6 drill bits so far. When I get all the metal finishing done and get it all back together again I will be sharpening a lot of drill bits so when I do the video update I will let you know what I have found out. Regards, Mark

[@michaellinahan7740]

Mark, one of the reasons I would never have made a good air traffic controller is that I am not able to think in 3d spatial space but since the drill bit is angled on the platform and the platform can rotate isn't there a way that the heel can be relieved using the existing setup rather than make the split point accessory? I just can't seem to rotate it in my head. I noticed the indentations appearing in my collet block as well which is one of the reasons I added needle roller thrust bearings to the front and back of my build. Also it has just struck me that as you grind the drill doesn't the cutting angle of the drill change so the grind doesn't end up horizontal?

[@martinconnelly1473]

I think that the sector plate is not raising the angle enough for the Ø11 drill and that is why there is a heel causing problems. There is more metal to the left of the ground edge in a larger drill (above the cutting edge when in this grinding jig) and it is going into the area where it is leaving this raised heel. The use of the split point jig to raise the angle to grind away the heel supports this view. I think a variable sector plate may be needed to cover all the diameters that are being ground. I would experiment with a few representative diameters to see if it was too low for all of them or just larger drills.

[@Preso58]

I need to do some checking on the intended secondary relief angle which is set by the sector plate. I read through John Moran's notes several times but I think he only mentions a range of acceptable angles. I cannot even recall how I came up with the geometry of the sector plate and it's mounting hole position. I now have the machine in pieces so I can do the metal finishing. According to my CAD model, the secondary relief should finish at 22.87 degrees. I may end up making a couple more sector plates to give a bit more clearance. They are simple parts to make and I might as well anodise them all at the same time. They are easy to swap out too. Regards, Mark

[@a0cdhd]

Good afternoon Mr Presling, Are the chips produced from drill bits sharpened with your newly completed bit grinder uniform in shape, thickness and texture as those produced from a commercially ground split point drill bit?

[@Preso58]

It's hard to say since they get flung all over the place. I would like to try a freshly ground drill on some good quality steel though. The hot rolled stock I used can be a bit gummy and stringy. I can tell you that using the automatic down feed on the Bridgeport gives you a consistent feed rate and the chips had a uniform spiral although they do break off due to centrifugal force. I think the thing that I was most happy about was the way the drill can cut without needing a pilot hole and it can start accurately without wandering or orbiting. Regards, Mark

[@FredFred-wy9jw]

Mark .., have a drill doctor… works well for bits up to 3/8” or 7/16” (10 or 11mm) and it is difficult to get a good grind on bit larger than 1/2” (13mm), it is the “larger” model that is supposed to grind larger bits. So, I plan to make a 4 facet grinder scaled up with a larger er collet. Great series … ps are your cad drawings available??

[@Preso58]

I am working on the drawings and the CAD model. I want to be sure they are up to date. There are always revisions going on and I will announce when I am ready to share them. You will be able to download them from DropBox (for free) when they are done. Regards, Mark

[@larryw5329]

Drill Dr are POS. I had an older one, I couldn't get a good grind and made a jobber drill a stub drill trying. So I bought a 750x (or something like that) and I get the same results. I ended up getting an old Gorton cutter grinder that should do what this kit does.

[@FredFred-wy9jw]

Thanks Mark … I really appreciate your efforts … I am currently building a 1.6” scale steam tractor…. If I had a part for every revision of my cad drawings I would have a least 10 tractors

[@KW-ei3pi]

Hey Mark I've been wanting to build a Tool and Cutter Grinder that would grind four facets. I saw this design online but I rejected it because I felt it was way too fiddly, and required too many steps to be practical. It would seem like it would take hours to sharpen just a few drills of different sizes. There are several commercial options available that require fewer steps and would be very fast. Small drill bits don't seem to be as critical when it comes to sharpening and I can usually sharpen them by hand on the bench grinder. So, let us know after you have used this for awhile if it's practical, or ends up on a shelf not being used. And how long it takes for you to sharpen a couple of dozen bits. Also, I would have thought it would be relatively easy to sharpen 2 or 4 facet drill bits on your D-Bit grinder??? Thanks. Regards.

[@Preso58]

The issue with a D Bit grinder is that you need a 5C collet for every different drill bit size you want to sharpen. I tried and failed to fit a 5C to ER collet adapter to my D Bit grinder due to a lack of space between the work head and the grinding wheel. I find that it takes about 2 minutes to sharpen a dull bit on the 4 Facet machine. It takes longer if the bit is chipped or badly ground in the first place. Once it has been sharpened with 4 facets it should be even quicker to do a regrind. I am just finishing up the last video in this series and I will try to demonstrate the entire sharpening process in one go and do it in real time to demonstrate how long it actually takes for one bit. Regards, Mark

[@KW-ei3pi]

@@Preso58 Good point about the collets. I had forgotten about that. It's what has prevented me from buying a D-Bit grinder. I had the opportunity to buy a full size Tool and Cutter Grinder recently for $900 US. But it was missing the work head and without it, the machine is pretty much useless. I'm trying to design a work head, but it's not easy. Thanks Mark. Regards.

[@poetac15]

Awesome

[@timogross8191]

I guess "the contraption" plays in an entirely different league than a drill doctor 🙂. Your motor alone seems to be more expensive than a complete drDr. Waiting for the next video..... my educated guess is that you will be able to get a decent result with very smallish drill bits. Saving money is always a matter how much $$ you factor in for your own work time.

[@Preso58]

Timo, my need to be able to sharpen small diameter drill bits led me to this design. I have seen the "wishbone" type sharpener and I believe they work well but the issue always seems to be holding the myriad of different sizes when you get into metric, imperial and number drill bits. Although I haven't tried anything under 4mm yet, the notes say that you can sharpen down to about 1.5mm. We shall soon see. Regards, Mark

[@ccbproductsmulti-bendaustr3200]

👏👏👏👏

[@tsirron]

Hey.. what is the price point for this unit when in production? I will take one. Jk looks good

[@Preso58]

For a one off? It's never going to compete with a Chinese knock off drill doctor. This is definitely a shop made tool and only if you're prepared to put in the time and not worry about your hourly rate. Regards, Mark

[@iTeerRex]

Forgive the noob question, Mark. I thought a Dbit grinder could do this. So what can it not do, that you made this tool?

[@Preso58]

You can grind a 4 facet geometry on a D bit grinder and I have done it that way but you have to have 5C collets for every size of drill bit that you want to sharpen. My Deckel Clone D Bit grinder wont' take a 5C to ER collet adapter either. There simply isn't enough room for it to fit. Also, you lose all the alignment when you change the angle of the workhead from the secondary to the primary clearance angle using a D Bit grinder. I find it takes about 4 times longer to grind a single drill bit on the D Bit grinder compared to the dedicated 4 facet grinder. Regards, Mark

[@iTeerRex]

@@Preso58 Thank you 👍

[@mikegregory460]

why is there such a small stickout from the collet?

[@11THEFEZMAN11]

Vibration and support drill bits love to chatter then snap

[@Preso58]

The design is a compromise. Smaller drill bits need to be held very close to the collet or they will deflect too much or they will snap. The bigger bits could be held with more stickout but you would need a bigger trunnion. I am going to look into whether it is possible to have a second set of holes for the positioning of the collet block. I would just need a different gauge to set the position of the drill tip. Regards, Mark

[@glennstasse5698]

That drill sharpening outfit is quite nice! It seems really complicated though composed of pretty simple part. Congrats on completing a really useful tool. BTW you don’t have to wonder any longer what the first European settlers thought when they first saw a kangaroo. I can stand in for them. My first reaction was, and remains!, WTF? How did you guys down there manage to produce THAT? I’m headin’ back to a place where all 4 legs are the same size and the animal doesn’t come from some weird AI program! Thanks as always for the footage….

[@Preso58]

I was watching the mother kangaroo lying down with the joey's legs and tail sticking out of the pouch the other day and it reminded me of the scene from Alien where the xenomorph burst out of that poor guy's chest. Interestingly, a female kangaroo can have one joey in the pouch, one in her womb and one independent all at the same time. Regards, Mark

[@okoustrup]

Why don't you just bring the drill bit 1-2 mm further out from the collar?

[@Preso58]

Unfortunately, the geometry of the setup is very specific. In order to be able to grind smaller drill bits you need to have a very short stickout otherwise the drill will deflect or break. This means that there isn't a lot of clearance between the face of the wheel and the nut of the collet chuck. If you were to move the collet block back further for the bigger drill bits you would also need to raise the height of the collet chuck to keep the intersection point of the axis right at the axis of the trunnion pivot points. I guess you could make the whole machine larger and build in multiple geometries but it does work as it is. You just need to concentrate and get into a rhythm when changing from one operation to the next. Regards, Mark

[@okoustrup]

@@Preso58 Thanks a lot for your answer. I myself got similar thought when I had sent the comment. I enjoy your video's even though I'm retired without a machine shop, so please continue your good work.

[@martinconnelly1473]

I have a suspicion that the wavy line where the two facets meet is caused by the linkage for operating the slide. There is possibly unwanted restraint in some of the joints that is caused by the linkages trying to rotate at 90° to the pivoting axis but since there is no way for this rotation to occur it pushes the main plate up or down. Just resting a hand on the operating knob could cause this twisting since the long arm is flexible and will easily be pushed down by the weight of a hand. A ball and socket linkage would normally be used to cure this issue.

[@Preso58]

I think I have found the source of the wavy line. There was one countersunk head screw under the collet block base that was protruding very slightly. It was causing the collet block to rock as it was traversed. I only found the error when I started the split point grind process. I will give an update on this later. Regards, Mark

[@opieshomeshop]

I don’t know. A lot of harmonics going through that wheel.

[@Preso58]

I am keen to see how the 200 grit wheel behaves. Regards, Mark

[@opieshomeshop]

@@Preso58 I'm having a similar problem and the harmonics are ruining the surface finish of a pin gauge I'm trying to make. Mine is coming from the motor though and not the wheel. When I was a mechanic, we had rubber straps to put on brake disks to stop harmonics and it worked really well.

[@gangleweed]

A 6 point grind???.....thjis is getting a bit complicated.......might as well just hand grind with a gauge to conventional point geometry.

[@Preso58]

Try doing that on a 2mm diameter drill bit! My eyes aren't that good and you have no doubt seen how shaky my hands are too. I like that the accuracy is built into the grinder. Regards, Mark

[@gangleweed]

@@Preso58 Yes, tired eyes need all the help you can get..... I use a wishbone type drill grinder or lapper on a diamond lapp.....whatever...... to sharpen my drills from 3mm down to 1mm.......the wishbone type drill sharpener was around in the 50's so I made one for myself.