The quest for straight jointer knives

Sharpening jointer knives straight requires a flat surface and something very straight to clamp the knives to.
woodgears.ca/jo...

[@forrestaddy9644]

Way 2 go! Matt does it again. You clearly identified in neat succession the problems and pitfalls a home woodworker encounters sharpening jointer and planer knives or truing hand plane soles with minimum resources. For example, what seems flat (like glass or stone counter top) is seldom flat and if thin deflects enough to screw up precision operations performed on it. The dial indicator and mag base you demonstrate detects only constant sphericity. I strongly recommend a home and small shop owner purchase a cheap import 12 x 18 granite surface plate. It costs about the same as a good 10" table saw blade and will last a lifetime for abrasive sheet lapping and other uses a jointer table or table saw may not satisfy. Caution!! Do not lap directly on the granite plate with loose abrasive or valve grinding compound. Granite wears about 5 times faster than cast iron lapped on it. Always use sandpaper abrasive side up. Even then, clean loose abrasive from the back of the sheet before laying it on the granite flat. I pontificate with some authority: I'm a retired machinist with wide experience with woodworking machinery and allied problems -o and I'm a woodworker myself. I hope Matt doesn't mind my interfering in the flow of viewer comment but the points he raises in this video are the very points I've raised for many years in direct consultation and later message boards. I'm gratified he so ably addressed the topic of sharpening jointer and planer knives and flatness in general.

[@StefanGotteswinter]

What you are measuring with the indicator on the plate is called "repeat reading" and an actuall part of testing for example surface plates (There is even a specialised tool for that, called a repeat-o-meter) And as you notices it is not very good to locate very large concave/convex geometric errors ;)

[@CreaseysWorkshop]

I don't know why he didn't just put the blade in the surface grinder. Much easier!

[@AntonBabiy]

John Creasey didn't know he had a surface grinder 🤔

[@CreaseysWorkshop]

Anton Babiy doesn’t everyone?

[@AntonBabiy]

John Creasey I'm afraid we are talking about different machines... I'm talking about that thingy with a spiny thingy that also has a slidy table and a squirty thingy and it goes bzzzzzzzz pause bzzzzzzzz pause bzzzzzzzz pause well you get the point and I have to go to sleep. It's 1am here after all

[@StefanGotteswinter]

I have a surfacegrinder ;)

[@Mr2at]

I learnt quite a bit from that. It felt like the good old days of KZbin again

[@andregross7420]

Matthias, your dial indicator setup was identical to a Rahn Repeat-o-meter. This tool doesn't measure flatness, but consistency in curvature. You found this out the hard way!

[@ewowoi]

Sorry, but what is the difference between consistency in curvature and flatness? Flatness is just the absent of curvature in local area

[@Waffles783]

@@ewowoi a sphere has consistent curvature but is not flat. hence the issue in the video.

[@PBMS123]

@@ewowoi well if something has a consistent curvature, that is, the slope is the same whereever on the object. If his granite was concave or convex the dial indicator wouldn't move because no matter where you put it, the drop at that distance (the distance the arm is from the dial indicator base) is always the same.

[@TJStellmach]

@@PBMS123 You mean the slope *across any fixed distance* is the same everywhere, of course. Consistent slope everywhere over variable distances would be flatness.

[@eln74]

Thanks Mr. Wandel, this videos are the true spice of a real woodworker, not some lousy sponsorship, we can't thank you enough!!!

[@fxm5715]

Fun fact: One of the ways to make perfectly flat reference plates is by lapping them against each other in sets of three. Once they match each other in each possible pairing, it's impossible for any of them to be convex/concave.

[@lanceeverett5108]

1) I am very impressed by your process and patience 2) Thank you for showing how involved this. I will now not mind paying a blade sharpening service.

[@MikeGusFifteen]

Can confirm, work as an installer in a granite shop for countertops. We go for uniformity over flatness (although it is still a large factor). Pain in the butt when gluing a seam together though!

[@stuntmanmike5364]

This is probably one of the better videos I’ve seen on setting jointer knives. Thanks MW!

[@HondoTrailside]

Interestingly, even granite surface plates do not retain their level, unless properly supported on three points, and regularly checked and fussed over. Some very good deals are out there online for second hand surface plates. I found one that was some incredible size like 6'x10' by 10", it was enormous. And a beautiful pink. it was a Starrett, inspection grade unit, and seemed perfect cosmetically. The only deal the guy had been offered for it was y some guy who wanted one to use under his woodstove to meet fire safety provisions. Geez...

[@PBMS123]

A starrett surface plate used as a fire proof woodstove mount? that would make any grown engineer cry.

[@HondoTrailside]

Conversationally, since most people don't have the space: Living in Toronto (industrial base) I have owned 2 K O Lee sharpeners, they work like a surface grinder but they are designed to sharpen or make tools like these knives, or complex milling machine bits. They don't seem very popular as I got one for 200, and then sold it to a guy who really wanted it, for 300. I found a smaller one for my uses, that was free. It is usable for small surface grinding operations, though it isn't built to perfect accuracy for that function. Works for me though. If I just have nicks in my blades the first thing I do to correct those is offset the knives slightly so the nicks on the blades don't line up. Not all jointers adjust that way, but it works on my General. I once ran a board that turned out to have screws in it through my planer, and got 1/4" chips in the knives. Still managed to offset them as there were 3 blades. I plane plywood by hand, since it is so easy to sharpen the smaller blades. I also use a carbide trim bit at times, against a pattern. When building my trimaran I had the same wooden plane in the shop for 6 months. I planed wood and glass covered wood all that time and it got duller and duller. Eventually it would only allow a really rough cut, and I had to re face the base of the plane when I was done. But even that was more of a pleasure for me than changing jointer blades, not that a jointer would have worked on the boat.

[@AvinashArora0]

I love how much I learn from your casual shop maintenance.

[@rayleder3705]

I bought a simple sharpening jig about 5 years ago, called the Deulen Jig. It was about $75 at Rockler, but does a fantastic job of sharpening planer/joiner knives. Keeps them flat, too, during the process.

[@walterwhite279]

I recall the first time I watched my grandfather sharpen his planer knives. Sharpening stone attached to a stick that slid along a bar parallel to the cutter head. Planer running. No need for removing the knives. Super fast and extremely dangerous. "Don't ever try this, boy" still rings in my head to this day. Decades later, and decades ago, I developed my own unique sharpening techniques as head of production and maintenance at a millwork shop. Still get a kick out of watching others try to figure out what is going to work for them.

[@matthiaswandel]

Sounds like a good way to ruin knives. You need the back edge angling down, otherwise they won't cut right. And if you put a stone against a spinning head, back edge is just tangential (no good)

[@1pcfred]

I'm glad you said it. You saved me some trouble.

[@walterwhite279]

"The quest for straight jointer knives" - Considering that "straight" was the primary focus of the video and your quest to finding a process that worked for you, I think my comment had merit in that regard. I certainly wasn't recommending it to anyone. Having said that, I'd also like to add a bit that will no doubt also bring about some controversy. First off, the use of Grandpa's technique created a dual bevel, the first part of which was not flat. And the more he sharpened the knives, the larger that portion got in relation to the remainder of the "normal" factory bevel. Eventually, the curved portion of the bevel would take over the entire bevel, leaving a rather large convex surface behind the cutting edge which would stay in contact with the wood as the cutter head rotated.... and should burn the crap out of the wood. I didn't think of such things when I was younger, but I did ask Grandpa about it when I got older. According to him, he only did that on one of his surface planers, and the reason was because it significantly reduced grain lift and tearout on curly maple... which he used to cover the interior walls of his home in a unique herring bone pattern. He said the feed rate and cutter head speed were also not standard but I don't recall in what way he had changed them. Not that I would ever use that old cobbled together machine, but I sure would like to have it sitting in the corner of my shop just for nostalgia.

[@1pcfred]

You need relief on a cutter regardless of the speed or feed rate. You're not going to get that by running a stone on a mounted cutter either. You will end up with zero relief then. What you have there is an interrupted wheel. You need teeth!

[@TimesWatcher]

Wire brush is a great tip! Wish I'd used that habit on my very first run on my very first jointer. I just picked up a load of black cherry for a set of stair treads I was building, and on the very first peice... I ran through a staple... right in the middle of the blades. Years later, after giving it to my uncle to use for a while I'm getting it back... and it still has the divot ridge running down any work that uses that part of the blades. Time for me to get jiggy with this method you showed and take the blades down past the chip. Good vid, thanks.

[@kristofbarta2964]

I was scared of changing the blades on mine since the jointer arrived but this seems doable now. Thanks Mathias!

[@chuckyz2]

Invest in 4 or 5 inch thick granite surface plate. You will love it. Get a grade A. You can precision grind all your tools including your straight edges. I use it for lapping hand plane bottoms and squaring the sides, blades, straight edges and checking flatness of all the above and more. Mine is 2'x3'x4.5". I wish I had 4' or longer. How precise does this stuff have to be when working with wood? That will depend on who you ask. Myself when using straight edges to check flatness, I look for light between the surface where many use fueler gages. And most are happy with a .001" variance. Light can shine through that easily and 1 thousandth is far from what I would consider precision. I think I read that you need to be in the millionths before light cant be seen. That would look like .00005. When you used your dial indicator over the piece of wood you just ran on the jointer....that would drive me nuts. It looked like at least 3-5 thou. Surface plates are expensive when bought new, especially large ones and they are extremely heavy. Mine is 500 lbs and it wasn't fun to load, unload and set up. But It was worth it to me and I am very very happy to have it. You can pick them up for very cheap used but then need to either take them in to be lapped flat or they will come to you for an extra few hundred depending how far they have to travel. Great care must be used with them to maintain dead flat accuracy for the longest periods between touch up lappings that are expensive. If you are careful to not drag heavy items across the surface plate and not use it for a bench top and protect the exposed surfaces from abrasives like sandpaper dust that will wear it when swept or wiped clean, you can get many years between touch ups not being in the ultra metrology precision based fields.

[@pheenix42]

I understand your dilemma...in printing, our large paper cutter knives need to be sent off to a specialty grinder service to make sure that they're done up correctly. Good job!

[@MRrwmac]

Very informative video! Excellent presentation and camera angles! Thanks Matthias!

[@TheScytheMoron]

Matthias: You are a gem on youtube!

[@bernwoon912]

Very nice exploration of flatness vs repeat-ability. Even on a perfect sphere you would get remarkable repeat-ability.

[@NormReitzel]

One way you can check surfaces like your granite slab is by using a quartz optical flat and a monochromatic light source. I bought a "green" LED from Terralux that is about 535 nm and linewidth is only a few nm. My quartz flat was bought surplus (it has edge bites) but it clearly shows rings on spherical mirrors. I was extremely impressed at the care you took with your knives. I'm a lazy ex-engineer and I just installed replacement knives. You may know ex-government people -- just throw money at a problem,.

[@michaelslee4336]

M, when you were dragging the base and indicator along and saying it’s straight as the indicator is not moving I was screaming NO! In my my mind. But of course you worked it out and I never really doubted you anyway. Cheers Michael.

[@Steinblocksebi]

This made me appreciate my carbide jointer knifes a lot.

[@thomasloven]

Instead of adding a paper under the aluminium extrusions, you could also turn the cutter head a bit. The knives will be at the same height as the outfieed table if they are at the highest point of the arc while contacting the extrusions. If you turn it a bit, the blade will go down, and have to be a bit further out to contact. That's what I do. This assumes, of course, that you can still reach the screws with the cutter head turned. I also use magnets to hold the blade in place (because my springs have seen bettter days...) and place them on steel rulers. That way I can get the offset from dead center consistent between the knives. Works a charm!

[@robertstigter9195]

Thank Mathias, great learning video. Ist's a shame that all these "complainers" and "I know-better" commenters did not understand the sense of these kind of videos. What can I do myself, what mistakes do I make and where are my limitations. I know, buying stuff is always easier, but "trial and error" makes more fun and is training the brain. At the end this philosophy made you one of "the Masters" of the DIY Community. Have a Great Weekend.

[@RossWilliamsDC]

Great jig idea, but jee-zers what a pain. Makes me so happy my 12" Inca Jointer/Planner has the Tersa knife system, which as you probably know allows blade changes in about 30 seconds per knife. They then self-align and level perfectly when you turn it back on. They are however disposable, but are inexpensive, last a really long time and are sharp on both sides. I replace mine about once a year for about $23 US. I'm surprised more manufactures don't offer the Tersa system.

[@migalito1955]

Nice. Sharpening, whether knives, chisels, plane irons or the blades of electric planers need held at the fitting angle and anyway that you can achieve this has my vote. Fortunately for hand planes I have a commercial jig, but everything else in my shop needs a DIY approach.

[@moc5541]

About cheap flat surfaces, I have spent a total of probably three hours in HD looking for flat floor tiles--- per the advice of Paul Sellers and at least one other famous KZbin guru (I forget who). I had about given up, but finally on my second visit I found one: MSI Carrara 12 in. x 24 in. Glazed Polished Porcelain Floor and Wall Tile . To check it I had borrowed a framing square from the hardware department but pathetically the new model framing square by Empire has a rough edge! So I went back to get a better framing square. But the best trick that I found for finding candidate tiles was to flip them over face to face. Every pair that I tried, until the last, rocked at one corner when I pressed on the top one.

[@moc5541]

The William Ng video "Fast and Easy Way to Sharpen Jointer and Planer Knives" offers an interesting contrast.

[@michael-dm2bv]

comments were disabled on your cutting board video but wood counters are usually oiled with mineral oil. its fun to buy at the drugstore as its a lubricant laxative, so buying more than one bottle will give you the appearance of being highly constipated.

[@ElectraFlarefire]

Trick for using non-waterproof sandpaper: Use alcohol. Only tried denatured, but IPA should also work. Oil might also work, but it's not something I've tried.

[@fittony]

can you explain why it doesn't make the paper mushy? i would have presumed any liquid would have made the paper mushy.

[@ElectraFlarefire]

Just depends on the paper and glues. Different liquids dissolve and effect different things, water effects the paper so use something that contains no water to do the same thing(Lifting out the metal particles and lubricate) works fine. So while it makes the paper 'wet' it doesn't weaken or soften it. For the exact details, you'll need to look up the chemistry.

[@daviddaddy]

The water Soaks into the fibers and Weakens it, Alcohol and Oils Dont soak into the paper as much so it works a bit better.

[@g45h96]

The base that you have your meter mounted to is your reference, and the meter is your measurement. When you reference the piece that you're measuring at the same time, you're not checking if it's flat or not; you're checking if it's smooth. As you move up and down the granite, there are very little imperfections, no small high and low spots. The work bench had more small variations. If you set the base on the aluminum extrusion, and measured the granite, I'm sure you would start the see that it is not flat

[@matthiaswandel]

Yes, as explained in the video.

[@nobodyuknow2490]

For flattening and polishing a surface for absolute flatness, you can use wet/dry sandpaper on a thick piece of glass. When glass is made, it is incredibly smooth and flat by virtue of how it's made. Many times I've put a very thick piece of glass I keep for that purpose on a towel, and at my workbench/table proceed to get a perfectly uniform surface.

[@1pcfred]

Perhaps glass is really flat when it is made. We usually get glass sometime after it's been made though. I've seen glass bend. When it was bending it wasn't too flat then.

[@nobodyuknow2490]

well glass can bend a very little, but only when unsupported as well, hence putting it on a table/workbench...

[@stephboeker7835]

Very informative and interesting. You are amazingly thorough, concise and have a way w/ your productions. Thanks for sharing,Sincerely ....................

[@thetheo2002]

Really great Mattias. I was going to get some scrap granite from a supplier and do much the same. I like granite because it is used as a reference for a number of critical machining processes and also geeking out a bit, there was an old scientific american build your own gravitometer article and that was built with glass plates glued together for stability/inertness. I would not have thought to check with a reference edge early enough I bet though so good experiment and debug there in your video. I am buying knives sold from Dimar, a place out of Ottawa and they are some kind of tungsten steel, so I don't feel the need to switch to inserts on a durability basis. When sharp I don't see heavy tear out on curly maple. I did have to switch to 5" hose to avoid plugging up the dust collection when planing or jointing. There is a very good sharpening service, quality saw, apparently here in New West and I will try them as well. I currently take the blades to KMS, and charge by the inch and this adds up to the cost of the blades after not too long. I tend to eventually have large nicks that need a cold wheel grind not just sandpaper I think so my first pass was going to be something more elaborate than you have done here. Curious what the pro machine looks like for this process. This channel is an invaluable service.

[@ozannesr]

I use an oven glass window, the inside one, very flat, toughened and the corners are all nicely rounded. usually there are only a few screws holding it in so easy to get at too

[@muskokamike127]

just for future reference: for not much money you can get jigs that will hold your knives at the correct angle for sharpening/honing. You can do two at once as well. I think busy bee sells them. Another old machinist's axiom: if you do a figure 8 pattern in your honing you are sure to get all sides equally honed. (don't ask me how, an old machinist told me it lol)

[@jimbo2629]

If you regularly hone the blades in situ, you don’t need to take them out so often. Don’t let the ends of the wood touch the floor as this invites grit.

[@paulkolodner2445]

When you hold a ruler or straightedge against a surface to look for deviations from flatness, it helps to have a back light.

[@user-px7zf9tr4y]

Молодец Матиас! Респект и лайк. Как обычно, из говна и палок сделал заточной станок! Молодец! Жалко что языка не знаю и перевести речь не могу, только по русски понимаю.... Well done Matias! Respect and like. As usual, I made a grinding machine from shit and sticks! Well done! It’s a pity that I don’t know the language and can’t translate the speech, only in Russian I understand ....

[@1873Winchester]

I'm too lazy to remove my knives so I've just been running a diamond hone over them using the table with some masking tape on it, has worked pretty well.

[@petercollin5670]

I sharpen my 6" jointer blades by mounting at the correct angle against a flat surface, and rubbing water stones across the top. It would be much trickier with long knives doing it that way. But I get good results.

[@1pcfred]

Longer blades being trickier is one way of putting it I suppose. Saying it sucks worse would be another. Take it from a guy that sharpens 13" long thickness planer blades.

[@Vsor]

The slab may be perfectly flat, and the table is just bowing slightly. With some quick calculations, you should see a flexure of about .0003" on a slab that size if supported by 2 sides. It looks like you have something similar to that (remember the indicator indicates double using his setup). All materials flex, this is why surface plates are like 6" thick. You could probably shim it in the future, just test it with a feeler gauge and a ruler before use.

[@mpetersen6]

Used to have to sharpen the joiner knives for the wood shop at work. A surface grinder is the way to go.

[@MaxMakerChannel]

Its one of those things that is fun to watch Matthias do by hand, but I rather send mine off to a service that does it for me.

[@shadowslayer552]

You should get a lansky LS1 its the best sharpening system i have used and ive worked in a knife store for 5 years. They have loads of different grits sold separately. Absolutely worth it and cheap on amazon.

[@blhale1]

For my 15" planer, which has 3 blades. I take a 15" or longer piece of wood, cut 2 45 degree opposing slots in it. Put the blades into the slots and rub with a diamond stone, counting the number of strokes. As the blades are rotated out several times during the process, any variation in the straightness of the cutting edge is canceled out

[@matthiaswandel]

unless your slots are slightly off straight, in that case, rotating the blades only ensures they all get the same curvature.

[@itamarcarrijo]

Impressive, guy. Amazing job. Congrats.

[@JeremyBuehlerJWB]

What? Legendary always flat granite not actually flat? You may have just shattered a KZbin sharpening belief system. ;)

[@frankingram3382]

When you put messages on the screen like you have in this video; please leave them up longer for us "old people". We can't read as fast as we used to. I enjoy your channel very much. God Bless my friend.

[@matthiaswandel]

there's a "pause button" on the bottom right for such occasions.

[@crystalsoulslayer]

If you're on the computer, you can press the left arrow key to instantly rewind the video by a few seconds. On a phone or tablet, double-tapping the left half of the video should do the same.

[@mcearl8073]

A few years ago I got a machinist slab very cheap, I forget the company but they definitely lost money on that deal, it was a thing where they had free shipping and a sale on this big heavy slab that probably cost quite a bit to ship. The machinist granite slabs are certified to be a certain flatness.

[@andywatts9682]

As Mr Levittan noted, you can not check the flatness of a plate by having the base of the indicator on the surface to be measured. The indicator base must be on an adjacent known flat surface and the tip of the indicator on the surface to me measured. Later in the video you pretty much confirmed your problem.

[@matthiaswandel]

As pointed out in my video, you can not check the flatness this way. Did you not notice that?

[@qwertt14]

Matthias just proved how Earth can be round yet seem flat from ground level. Take that, flatearther!

[@coalitionofrob436]

Lucky you found the springs! I don’t know how I haven’t lost mine yet

[@BadPete999]

There's many highly specialized shop that can sharpen your blade to a very high level of precision that you could never achieve with simple shop tools ! there always a limit to how much money you can save to the detriment of precision ! I always have two set of knives on to send out and one to work !

[@1pcfred]

You keep believing that.

[@18roselover]

I/ve got the magnetic jig and use an use a magnetic dial indicator to get the knives.oo1 above the plane of the outfeed table instead of .005 paper, it a 33 yr old chiu -ting jointer

[@SurajGrewal]

Finally,a rare video of Matthias, working with metal.After all,wood can't cut wood.

[@1pcfred]

I don't know about that. You can cut wood with paper. There's videos up of people making paper discs and mounting them on high speed rotary tools. It's incredible.

[@baseballrecruit]

You're great at making complicated tasks seem simple... too simple haha.. too many "why didn't I think of that" moments when I watch

[@shonuffisthemaster]

you cant check for the flatness of a surface plate with a dial indicater, all you checking is smaller dips and bumps. to check flatness like that you would have to have a bridge

[@JohnHeisz]

Genius idea for that jig! Oh, wait...

[@Margarinetaylorgrease]

You did it first? Or "it's on" and you nearly forgot?

[@rimmersbryggeri]

The word genuis is often used in a hyperbolic way.

[@lettersandnumbers81]

The magnets were change for the sake of change though

[@LukeLibertyNoRulers]

So salty john.

[@sundaynightdrunk]

lettersandnumbers81 I get the reference, but the magnets were an example of working smarter. A lot less work than piling weight on the extrusions.

[@AngryArmadillo]

Very cool! A real-world example of local vs global curvature.

[@thetomster7625]

thats why you don't use material straight out of the mill.... its gotta be machined first in order to be properly straight. Every material (especially wood, as we know) still has a thermal live after cutting (same with Metal, that doesn't cool down equally)... with one exception: Stone Thats why its the best Idea to use a sawn and pollished stone block for reference.

[@Sutoraida1975]

It looks like Kiwami Japan's blade sharpening videos are becoming quite influential. :-)

[@alec4672]

To get a truly accurate measurement my machine shop teacher told me in highschool ideally your always measuring from a fixed base and only moving the dial indicator along some sort of arc.

[@kerrygleeson4409]

Alec Ver Bunker Correct

[@crystalsoulslayer]

I had been wondering about that. If he had the base on the table and just rotated it around, it should have picked up even that slight belly, right?

[@MsSomeonenew]

But then your moving arm needs to be 100% solid, usually can't rely on moving parts being any better.

[@crystalsoulslayer]

The arm doesn't need to be 100% solid, just _more_ solid than the little... head... pin... thing. As long as it requires considerably less force to move that than the arm, the arm will stay put, because physics has a thing about paths of least resistance.

[@alec4672]

MsSomeonenew Move the work piece in an arc then.

[@flyingflapjack5133]

Should set knives with dial indicators to get all 3 exactly the same. Mount indicators on a 90 degree inside corner and rock jig forward and backwards on cutterhead, across knife to get the high spot. You could use a 2x2 aluminum angle, 2 inch long for example. You'd be surprised how far off the knives actually are. The result is knives last lot longer between sharpening

[@matthiaswandel]

they were set very consistent when I checked them. Letting the blade drag a straight piece of aluminium is quite sensitive.

[@NSResponder]

Wow, didn't know anyone was still using one-piece jointer knives anymore. I thought just about everyone had upgraded to spiral cutters.

[@1pcfred]

For what a spiral cutter costs I could get some asshole to plane all of my wood for me and I'd still financially be ahead of the game.

[@ncooty]

@9:43 If you're planing reclaimed wood, run a metal detector over it or your planer/ jointer might find a nail/ staple/ screw for you.

[@construction-productscemen4935]

The video is awesome. I like your idea.

[@dangermartin69]

Wouldn't it be easier to take your 1X30 belt sander and get a few knife grinding belts for it and then make a jig to keep the planer blade at the correct angle and move it back and forth across the belt?

[@matthiaswandel]

it would be very difficult to make this accurate enough

[@1pcfred]

Nothing worthwhile is ever easy it seems.

[@dangermartin69]

@@matthiaswandel I tried it for mine, and they are only 6 inch blades so not as hard to handle. I clamped a piece of wood cut at 45 degrees to the deck of the sander so that the bevel would be parallel to the belt, and once you get a feel for it to run the blade consistently, it worked pretty good for me. It would probably be more difficult with 12 inch blades.

[@Wordsnwood]

curious about the holes in that piece of granite. It is really thick!

[@1098DESMO916]

Wordsnwood (Art Mulder) It came from a cemetery, a bronze name plate would bolt on through the smaller holes. The larger hole would be used for a vase, that would flip over into the hole when not used. Search granite based marker with vase.

[@worldmenders]

A thick granite base is frequently used in bespoke test or production equipment in electronics and high precision machining. As the equipment is retired, the blocks show up on the surplus market.

[@wilbertbirdner1303]

it's his old toilet seat

[@TEAMSOTO]

My favorite wood worker/youtuber..Happy New Year 🎊🎉🎊

[@bobuk5722]

Hi Matthias. If my almost 70 year old memory is still working there's a 'trick' for creating a true straight edge using just three initially not really flat bars. I'm sure its Googlable if you are interested (TOT?). Maybe one time you could do a bit about the sort of tolerances you like to work to - and more about how you achive them and what sort of woods you would use and how well they hold? BobUK.

[@matthiaswandel]

yes, I'm aware of that trick. I just didn't feel like making flat bars before sharpening.

[@1pcfred]

That's called the rule of three. Three surfaces cannot agree with each other and all be out of true.

[@bobuk5722]

Hi Matthias. I'm not suprised! I was n't trying to suggest you should. Did n't mean it to come across that way. It's perhaps something to do when there's absolutely nothing else on. Me, I just buy a straight edge! Rather spend the time with my grandson. BobUK

[@petercollin5670]

I'm looking at the Lie-Nielsen catalog. They sell the Maine Granite sharpening station. Price tag - $1,300. Big slab on a wooden stand for doing just this procedure. I think I'd rather buy $1,300 worth of blades!

[@matthiaswandel]

for sharpening hand plane blades, my first granite piece would be more than flat enough already. But it doesn't say "Lie Nielson" on it anywhere, so it's just not the same :)

[@benjaminshaw4263]

I understood very little of this. But I enjoyed it anyway. Thanks.

[@kookyflukes9749]

Would you consider upgrading to a spiral cutter head. It would make a good video plus more importantly have the added benefit of getting 1up in Mr Heisz 😁

[@1pcfred]

Spiral cutting heads are only worth it in a commercial production environment. Otherwise they do not make economic sense. That still doesn't stop a lot of amateurs from being idiots and buying them. But it does give more thoughtful people some pause.

[@josiahbaker7811]

Can't be sure, but with the two opposing spring forces of the small spring and magnet, the lever arm length of the aluminum channel / magnet position might affect the final straightness of the blade

[@matthiaswandel]

I put the guides right above the springs

[@sk4lman]

I feel the need to show this video to flat earthers

[@osiris25bc]

LOL that's a headstone base!

[@63256325N]

Nicely done. Thanks for the video.

[@jeffsmith63]

if you find yourself a big old thick float-glass mirror, that and the granite should help git you a flat surface.

[@StuckInNE]

The big question is: Who hacked a hole in your thick granite slab?

[@davelowe1977]

A very angry beaver.

[@crystalsoulslayer]

Someone else said it's a type of grave marker, the small holes are for bolting on a nameplate and the big hole is for a vase. But it's way more fun to imagine a furious beaver hacking away at it because he needs a new curling stone.

[@Boyntonstu]

3 surfaces are needed to grind a flat.

[@theVonThompsons]

I have found Brent Beaches sharpening site to be great for nerding out on sharpening and metallurgy

[@ahbushnell1]

That slab is interesting.

[@GeahkBurchill]

I’m having the same problem. Trying to sharpen my thickness planer is freakin difficult!

[@1pcfred]

Yes it is. What's going on here ain't how to do it either.

[@warrantyvoid100]

I'm surprised you didn't leave the knives mounted and make a linear slide to mount the Dremel for sharpening. I'd really like to see that.

[@matthiaswandel]

I didn't want to mess up the knives. That's why.

[@TheRalliowiec]

The likes of Oxtoolco, Robrenz, & Stefan Gotteswinter are all yelling at the screen and crying at the same time.

[@StefanGotteswinter]

Lol! I love how he figured out that the repeat reading of the indicator is not very good at determing a large curvature on the plate.

[@1pcfred]

Yeah I seen Tom's video. This is just crap.

[@jrb_sland5066]

But for myself [and for many others, I suspect] Mattias has shown us all that step-by-step clear thinking will eventually get you to the truth. It also helps to have a second, thicker granite plate LOL - Great video!!

[@12345NoNamesLeft]

If you start with a tested flat surface, you eliminate that variable. $58 at Busy Bee for a 12x18, also KBC tools, Sowa, and others

[@kailesadler13]

That second piece looks like the base of a tombstone

[@jejo_jejo]

awesome ... great tip i will do that to my Wood Hand Planer

[@RajaKhan-np3gh]

I appreciate your thoughts.... wonderful dear

[@kevinmorin7965]

Thanks for the great quality video. I'd like to see plans to turn my Makita KP312 portable planer into a jointer- prefer you do this in aluminum (framing and structure) and given the cost of a 12" planer vs a portable in this size- the plans can be worth 1k US $ and be a savings.

[@brianrobertson6475]

I'm not usually critical, but that "flatness test" did sliding the gauge across didn't mean much. Not if the indicator was measuring from a fixed point... that would have made more sense...

[@pennyroyal3813]

Good thing you had that second piece of granite and a sheet of paper.

[@rpnp2]

you should invest in a large second hand surface plate

[@1pcfred]

Availability of such an item depends on where you are. Which is to say such things are not distributed equally across the globe.

[@rogertaylor712]

Tersa knives are miles easier to change. I made a jig of another youtube video. Just two beveled cuts in a block of wood. The knives sit in the slots and use a sharpening stone to sharpen both at the same time, identical angle. A bit of trial and error to get the right angle and Roberts your mothers brother! smalltown442 for that video.

[@vaseto1987]

I love this guy

[@CyberMacGyver]

8:05 "the thickness of a sheet of paper"- no special tools needed... just a sheet of paper 👌

[@Scrivscribe]

Great video Matthias! I'm curious what your thoughts are on spiral cutter heads with carbide blades?

[@SoundsFantastic]

Well worth the money. Self indexing inserts so no need to check flatness.

[@barkebaat]

Spiral cutter heads with segmented carbide blades are excellent ! Bought a Felder combined planer / thicknesser a coupla years ago and opted for the spiral cutter. Very pleased with it. It uses less power, makes less noise, gives a smoother surface (less sanding :-) and most important; it planes difficult grain very well. It's also easy to rotate the square cutting segments when they get dull. An added bonus is that if you nick one of them (damned sand !) you only have to rotate the damaged one, instead of changing the whole, traditional knife (and if you're like me, you'll change all the knives while you're at it. Damned OCD ! Damned sand !) Segmented cutters are the future.

[@vonantero9458]

They are great, but with any self indexing blades your planer needs to have a good fine adjustment for the outfeed table, as you can't adjust the blade.

[@Arnthorg]

5:30 aren't you taking more from the center when the ends go past the sandpaper? awesome video, as usal

[@matthiaswandel]

it does when I go past, but when I go back on the sandpaper, it cuts the high spots, so with every stroke back on the sand paper, it fixes it.