# Why use round magnets to build a knife rack?



## erezj (Nov 17, 2016)

Have been accumulating some knifes lately, after I got my hands on my unicorn, Shig 210 gyuto, I realized I need a wooden knife rack (just looking for an excuse to find a new project)

Anyways, there are some great threads on KKF, but the issue of pivoting has come up a few times, and besides, round is such a complicated shape for woodworking...

Why is every body sticking to round magnets? why not rectangular ones?

Initially I thought they were hard to find, but a short search on amazon got me some (https://www.amazon.com/dp/B01ID4R3L8/?tag=skimlinks_replacement-20)

appreciate any insight


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## Pensacola Tiger (Nov 17, 2016)

If you are working with hand tools, it's easier to drill a round hole for a magnet than a rectangular hole.


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## erezj (Nov 17, 2016)

Thats true, but I see lots of pros working with carpenters which can easily run a router all the way, or even just run the block on a table saw a few passes and get a rectangular groove.


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## LifeByA1000Cuts (Nov 17, 2016)

A 3" rare earth magnet bar is awfully strong. Likely too strong for a knife block.


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## jessf (Nov 17, 2016)

You want a silicone pad type surface with magnets behind it. Ive seen epoxy finishes that offer this. Will keep knives from spinning. Smooth wood offers no purchase on he blade and forces you to rely completely on the strength of the magnet.


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## erezj (Nov 17, 2016)

jessf said:


> You want a silicone pad type surface with magnets behind it. Ive seen epoxy finishes that offer this. Will keep knives from spinning. Smooth wood offers no purchase on he blade and forces you to rely completely on the strength of the magnet.



But the wood ones are so beautiful

And it seems that the owners are very happy with some of them.

As for the 3'' beeing too strong, thanks, that's important info, I guess I could use a smaller one.

but still why do every one use round magnets?

I'm just asking since I don't want to build a rack with square magnets, just to realize I made a mistake...

Thanks


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## jessf (Nov 17, 2016)

Silicone type finish. Ive seen epoxies that provide this finish. Meaning you can apply it to any material, including wood. It's a clear finish.


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## Pensacola Tiger (Nov 17, 2016)

jessf said:


> You want a silicone pad type surface with magnets behind it. Ive seen epoxy finishes that offer this. Will keep knives from spinning. Smooth wood offers no purchase on he blade and forces you to rely completely on the strength of the magnet.



If the knives spin, either there aren't enough of them or they are poorly placed.


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## jessf (Nov 17, 2016)

Or the rack is poorly designed. A single knife should hold in place and be secure or it sounds unsafe to me.



Pensacola Tiger said:


> If the knives spin, either there aren't enough of them or they are poorly placed.


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## DanHumphrey (Nov 17, 2016)

Wouldn't the _really_ easy approach be to epoxy bar magnets on the back of the wood? If they're stronger, you just make the wood thick enough to get the right strength on the knife side.


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## JayGee (Nov 17, 2016)

Could you give an example of the epoxies offering this 'silicone-like pad' finish?


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## niwaki-boy (Nov 17, 2016)

I've used both. I usually route a continuous slot and fill with either. The round ones are a pain in the ass to get polarity right and set in but I have tricks for that. Also the round ones are less likely to break if they attract each accidentally and they will! I've found that knives that have a more convexing will spin much easier than knives that have a flatter face also texture like ku plays in here as well. Metallurgy has a say also. And the finish put on the wood, how slick is it, can make good knives do bad things.
My next one will use two slots filled with smaller 3"bars, as I thin k now two rows are much safer. My supplier has changed their website and a whole bunch of sizes have disappeared so I guess I have to friend down to pdx and get that sorted. 
The relationship between the thickness of the substrate between mag/knife is the tricky part . I do a test piece that I can put shims in to get that right. There's a ton of playing around with these things and it's fun :doublethumbsup: and sometimes a little hair pulling as well ullhair:


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## jessf (Nov 17, 2016)

plastidip makes a clear rubber coating in a spray can. No need to hassle with mixing or thining. The epoxies ive seen ive never used so im not sure what the product name was/is. In general though, a rubberized finish would be what i would do.


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## malexthekid (Nov 17, 2016)

LifeByA1000Cuts said:


> A 3" rare earth magnet bar is awfully strong. Likely too strong for a knife block.



Why would it be too strong?

You just play with the cover of timber between the magnet and blade until you get the desired pull.


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## erezj (Nov 17, 2016)

Niwaki Boy

Thanks for the detailed answer, obviously you took the long route, although sometimes its sooo rewarding learning and finding your own path, currently I do not have the time, so I chose to learn from your experience, if you choose to share.

If going for the strip/bar solution, could you share the two most important data:
1. Type and measurement of the magnets
2. Width of buffering wood (the distance between the magnet and a knife)

appreciate the help and suggestions guys


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## aboynamedsuita (Nov 17, 2016)

Hi Erez, not sure if it may be helpful, but

I used round 1" diameter X 1/8" thick magnets in a 2x23 checkerboard configuration (you can connect the magnet side-by-side if you alternate the polarities). I also placed them on a 2x23 piece of sheet steel for duct work it helps keep them from attaching to each other, makes the magnet strip manageable to move and also increases the magnetism on the magnet side. I did some testing and found that 3/16"-1/4" worked for wood between the magnets and surface, too strong could damage the edge of single bevel. I had a professional woodworker do the actual building.

For a tip, when you epoxy the magnets into the router groove, you can/should put another piece of metal on the outside (ie where the knives would attach), as it helps keep the strip at the desired depth, and it will just slide off after.

If I were to do it again, I'd do two separate 1x23 strips about 1/2"-1" apart I didn't really have problems with rotation unless I put knives on at an angle and the magnet attracts the tang up or the blade down. I'd maybe consider using a bunch of smaller magnets such as 1/2" diameter because if I put small paring knives on, I can kind of feel the magnetism concentrate 1" on centre even though there is continuous magnetism with no actual dead spots. Since most knives are wider such as gyutos or sujis I don't have a problem but it's soemthjnf I've noticed.

Here's a couple pics, the back is seamless because the strip was installed inside the top piece and then to the riser piece










Feel free to email if you have questions, and glad you like the shig


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## krx927 (Nov 18, 2016)

erezj said:


> Niwaki Boy
> 
> Thanks for the detailed answer, obviously you took the long route, although sometimes its sooo rewarding learning and finding your own path, currently I do not have the time, so I chose to learn from your experience, if you choose to share.
> 
> ...



To give you some answers to your questions:

The pivoting of knives is a problem. When I made my first rack I needed to scrap it just because of pivoting.

What I did: I took 80 long and 9-10 cm wide (thickness of around 3cm) plank of wood and I asked carpenter to route a continuous slot 1cm wide as close to the front face as possible. He did a great job.
After that I bought round Neodymium disk magnets (10mm dia x 5mm N35). I bought 75 magnets like this and I was planning to stick them together and put them in the slot without any gaps (magnets sticking together).
My plan was also to control the magnetic force by adding a buffering wood in front of magnets -> no way to do this! Do not count on this. The process of getting the magnets in the slot is very tricky. Before I managed to get them in properly I had like 5 unsuccessful tries. The magnets just jump together in the wrong direction.
When I finally managed to put the magnets in the slot I used ordinary silicone to glue them in. 
There was absolutely no way that I would take them out again (before silicon) and adjust magnetic force with buffering wood. It was just to hard to get them in in the first place!

Unfortunately I immediately noticed that the knives are pivoting and the rack is useless 

So I started my second attempt. This time I asked the carpenter to make 2 slots (aprox. 3 cm apart) and I bought additional magnets. Luckily the first time I used silicone and it was relatively easy to get the old magnets out of the first rack.

At the end I got a rack that I need (80 cm long) but:
1. It was very hard to do it. I would probably not be doing it again. The tricky part was to get the magnets in the slots/groove
2. It costed me considerate money, probably I could just buy one for the same money. Unfortunately I never found anywhere one that would be 80cm long.

Now about magnets: with 2 rows of Neodymium disk magnets (10mm dia x 5mm N35) the magnetic force is a bit too strong (not that I will go and adjust it now - no way!). If I would do it all over again I would do the same but choose magnets that are about 30% less powerful. That would be just perfect.

I hope I gave you good guidelines on how to do it and how strong magnets to choose.


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## niwaki-boy (Nov 18, 2016)

erezj said:


> Niwaki Boy
> 
> Thanks for the detailed answer, obviously you took the long route, although sometimes its sooo rewarding learning and finding your own path, currently I do not have the time, so I chose to learn from your experience, if you choose to share.
> 
> ...



Sorry for not getting back sooner. Anyway tj and KFC bring up some good points. When I first tried to make one I saw a lot online and thought how can they be selling these things so cheap? And I started to look at magnet cost because after all in my mind I thought of selling some cool ones! So started thinking how can I get the best bang for the buck. So the first design that I still have up is a magnet arrangement .... down up down up down spaced 1" apart, sort of this wwww pattern. Not the best and has some quirks (missed polarity on one or two:scratchhead anyway it made me want to try something different so I got some bar mag 3"X1/2"x1/8" and just layed them in the slot. This works ok for smaller blades and bigger blades with flat faces but anything like say kono HD 270 will spin. Ok so two rows are going work better than this so back to the shop. I just got done with a double and this is the best way. I got the router to leave about 3/32" between mag/face and wow ... maybe a little strong! I'll play with some shims next week. This was made with two rows of 1/2" rounds back to back continueous because I don't like the magnets to dictate where I put the blade.
A couple of tips for dealing with those round ones... I do all this on a table saw meaning onto of metal this is important because as you place your mag in it stays put. I lay all the mags in their correct polarity on a piece of aluminum sheet metal on the saw as they too will stay in place. When I'm ready to start placing I just pull the aluminum off the table a bit so the mag comes off real easy cause you're just separating it from its neighbor and no iron underneath. As you add them into the slot put the min a little ahead of the last one the just slide to meet the last one. I use a center punch that about 1/4" and place the mag on the end of it and pretend that it's a game of operation the force of the tablesaw takes it right off. I also cut a piece of wood that slips into the slot so that I can control the already placed mags. This stick will also be used to keep them in semi-permanent as I dot, think spot weld, in a few places with glue so that if for some reason in the future the mags can be removed and re used. Round mags are a pain in the keester.
My source as I stated has changed what I can see online so I'm not sure what that's about. But they are showing at least one of the 3" bars I was thinking of using. Gotta dive down next week for other stuff so I'll stop by. It's always something :dontknow:

So erezj to answer your questions the round ones are 1/2x1/8 with about 3/32 and you can always shim, think thick paper to decrease pull.

Hope this helps.


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## niwaki-boy (Nov 19, 2016)

Sorry krx927... spell check decided that KFC was better apparently :bat:


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## bennyprofane (Nov 19, 2016)

Here is my magnetic knife strip: http://www.kitchenknifeforums.com/showthread.php/29640-Making-a-magnetic-knife-strip

There is no chance of spinning because the grip on the wood is much too strong. If you go through the thread there are some good tips by other users.


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## erezj (Nov 20, 2016)

Guys, its been a busy weekend (running all day after the children: 5,3 and 3 month) so didn't have the chance to thank you for the invaluable suggestions !

With your support, I feel pretty good about diving forward and initiating the project.

A few month ago, I was able to obtain 250kg of a 500 year old olive tree from the sea of galilee, I was waiting for an excuse to start ripping that piece of wood to pieces. 

will post some pictures once I get starting.


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## erezj (Nov 20, 2016)

Thinking about running the following configuration:

Magnets: N45 3"x 1/8"x 1/8" Neodymium Rare Earth Bar Magnet
Pulling Force: 16 lbs

Two parallel rows, 
Width of grove: 1/8'' (=3mm~)
Distance between groves: 1.5'' (=40mm~) apart
length :21'' (=530mm~)

have 7 of the below magnets in each row, total of 14


http://www.magnet4sale.com/n45-3x-1-8x-1-8-neodymium-rare-earth-bar-magnet/

What do you think?


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## Mucho Bocho (Nov 20, 2016)

I've been working on making two 24" X 3" magnetic knife holders for two years now. I've have four failed attempts, and finally decided to do it myself. 

Two rows of magnets are a must (learned in the first failed attempt). Basically I routed tow channels in each board and inserted 26LBS (3/4") neodymium round magnet cups http://www.magnet4less.com/product_info.php?cPath=95&products_id=576 placed side by side and held in with a screw in the center. The magnet seller recommended to place them all the same direction. I used 120 magnets. 

Then I slathered the whole face with a thick layer of bondo (wood filler) then when dried, sanded that smooth. Then I purchased a 1/16" veneer (zebra Wood) that I'm gluing to the face. Then just sand the edges. 

I'm in about $450, plus the cost of a router. I'll be dammed if it aint going to get finished though. \

The main problem I had with the other builds was the they were either too strong or too weak. I think I found a goldilocks solution, as all my knives, including stainless just click when place back. I'll post pics when their finished.


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## niwaki-boy (Nov 20, 2016)

Mucho Bocho said:


> I've been working on making two 24" X 3" magnetic knife holders for two years now. I've have four failed attempts, and finally decided to do it myself.
> 
> Two rows of magnets are a must (learned in the first failed attempt). Basically I routed tow channels in each board and inserted 26LBS (3/4") neodymium round magnet cups http://www.magnet4less.com/product_info.php?cPath=95&products_id=576 placed side by side and held in with a screw in the center. The magnet seller recommended to place them all the same direction. I used 120 magnets.
> 
> ...



Yes this I how I did my first one but I ripped a thin piece off the face and glued it back on... and as you suggest many options open up with veneers!


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## niwaki-boy (Nov 20, 2016)

erezj said:


> Guys, its been a busy weekend (running all day after the children: 5,3 and 3 month) so didn't have the chance to thank you for the invaluable suggestions !
> 
> With your support, I feel pretty good about diving forward and initiating the project.
> 
> ...



Oh man I can't wait to see a pic of that!!


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## JayGee (Nov 20, 2016)

erezj said:


> Thinking about running the following configuration:
> 
> Magnets: N45 3"x 1/8"x 1/8" Neodymium Rare Earth Bar Magnet
> Pulling Force: 16 lbs
> ...



I'd say those magnets are unlikely to be strong enough - and they also need to be closer together. The rack I'm making, which is almost finished, and has enough magnetic pull, uses two rows of round magnets with 7kg pulling power, placed 15mm apart. At first that wasn't quite strong enough and stainless knives would slide, ut then I removed more material from the front with a coarse disc on a power sander, and the strength increased significantly. You really want to get the magnets as close to the face as possible to be precise with your router.


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## erezj (Nov 20, 2016)

Thanks JayGee,

Ive found these new magnets:
https://www.aliexpress.com/item/20p..._9&btsid=bca4aff5-60f9-48f6-b1a6-95c57ec360d0

They are both stronger and cheaper, I'll will happily take your advice about reducing the distance between the rows.

If there is one thing I understood from this post, is that it is not easy to hit the sweet spot of amount of pull the magnets make on the steel, I'll design the rack in a way that I can reduce pull (by adding shims) or strengthen the pull (by adding a third line of magnets, or reducing the thickness of wooden buffer), in any case some preliminary testing will have to take place.

and I really thought this will be a simple project ;-)

here are some more tubes I found:
[video=youtube;so3O05N2b4A]https://www.youtube.com/watch?v=so3O05N2b4A[/video]
[video=youtube;fX96cjmf2IA]https://www.youtube.com/watch?v=fX96cjmf2IA[/video]


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## JayGee (Nov 21, 2016)

those look very strong.... I guess it depends on your configuration, but maybe do some experiments before you glue everything in. You could even use a piece of veneer to get a sense of how they will function. Ultimately the magnets are expensive so you don't want to get it wrong. Stronger will at least work. Too weak and the rack is useless. Watching these videos makes you realise that machines make all this much easier. I've seen lots of these mounted with keyhole brackets, but considering the size of the rack I made I was worried about the stability so have mounted it directly into the wall and filled the hole with plugs (using a countersink and plugcutter) another learning process.


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## BorkWoodNC (Nov 21, 2016)

I use 1/2"x1/2" N52 Cylinders routing a hole for each magnet rather than a continuous strip in the back of the rack and covering with epoxy.

A single row of these have proven to be plenty strong for the majority of uses. I use them for hanging tools (including hammers) in the shop as well as knives (including cleavers) in the kitchen.


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## BorkWoodNC (Nov 21, 2016)

Another picture of the magnet hole arrangement I use, single line


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## erezj (Jan 22, 2017)

Testing my picture upload abilities:


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## Mrmnms (Jan 22, 2017)

Looks excellent. Did you try different size /strength magnets before settling on these?


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## brianh (Nov 25, 2017)

Mucho Bocho said:


> I've been working on making two 24" X 3" magnetic knife holders for two years now. I've have four failed attempts, and finally decided to do it myself.
> 
> Two rows of magnets are a must (learned in the first failed attempt). Basically I routed tow channels in each board and inserted 26LBS (3/4") neodymium round magnet cups http://www.magnet4less.com/product_info.php?cPath=95&products_id=576 placed side by side and held in with a screw in the center. The magnet seller recommended to place them all the same direction. I used 120 magnets.
> 
> ...



Ever finish these, Mucho?


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## Mucho Bocho (Nov 25, 2017)

Brian I did and their great. Ill get a pic. Very happy w them. No issues holding all knives from clean stainless to clean carbon. Not too strong nor too weak. I think it was a good approach maybe not the cheapest though.


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## gic (Nov 26, 2017)

If more traction is needed, would a quick spray with this stuff (or equivalent) do what one needs:

https://www.amazon.com/dp/B00D0297BS/?tag=skimlinks_replacement-20


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## Qualitycookie (Nov 28, 2017)

erezj said:


> Testing my picture upload abilities:


That looks Teriffic.
Would there be any inherent drawback to magnitizing the knives?


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## erezj (Nov 29, 2017)

Thanks for the kind words...

I can share, that one year later and four new knives, it still works great!

A few conclusions:
Dont use round magnets, use the rectangular, its so much easier to build and has a continues magnetic field.
The art/secret of getting a good magnetic rack is in the amount of pull you feel for the knives, the reason it is art is since each of us likes it a bit different, design the build in a way that you can test and trial the thin piece of wood covering the magnets, start thick, and slowly reduce thickness (sanding) until you find your own sweet spot.

my 2c


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## brianh (Nov 29, 2017)

erezj said:


> Thanks for the kind words...
> 
> I can share, that one year later and four new knives, it still works great!
> 
> ...



Did you do two rows or one? One row always seems to have some spots where knives will rotate. Metal backing behind the magnets?


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## erezj (Nov 30, 2017)

I used two rows, I didn't need a metal backing, I understand it increases the magnet pull, but for the type of magnets I used and thickness of wood vaneer I had all the pull I needed


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## brianh (Nov 30, 2017)

erezj said:


> I used two rows, I didn't need a metal backing, I understand it increases the magnet pull, but for the type of magnets I used and thickness of wood vaneer I had all the pull I needed



Which magnets did you use again?

Edit: the ones on page one? $15 for two magnets is pretty $$$!


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## scott.livesey (Nov 30, 2017)

I use round magnets because of ease of assembly. I use 1/2" diameter, 3/8" tall N52 magnets that have about 22 pounds of pull force. I bought them from magnet4less on eBay, 40 for $30 the hole centers are 1" apart, just one row of magnets. the holes are drilled so there is about 1/4" of wood over the magnet. the wood was finished with a mineral oil and beeswax paste, any scratches go away after a fresh coat of paste. the only knife they will not support is my Foster Bros cleaver that weighs about 5 pounds.


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## erezj (Dec 1, 2017)

I did not use the magnets from page 1, it's been a while ago so I don't really remember which, but they were very cheap since I bought them from Aliexpress , I believe I made another thread where I describe the process of building the knife rack. All the exact details should be there


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## Devon_Steven (Dec 3, 2017)

I used rectangular magnets in my rack a couple of years ago. Pics here:

https://www.flickr.com/gp/[email protected]/9EA92C

These are neo-D N48s with about 2.5mm of wood between magnets and knives. Clothes pegs were used to stop them jumping together while the small spot of superglue under each one dried. Happened to have some expanding foam around that I used to seal in the magnets.

If I did it again, I would not leave any gaps between the magnets - even at quite a small distance between each, there is still a noticable 'flux gap' as you move the knives around on the rack.

Bork Wood's single magnet per knife (above) may be a more efficient approach in that (a) although one magnet per knife definitely means no continuous field along the bar - each knife goes in the same place each time; however (b) it's a lot lot cheaper on magnets.

And these magnets are not cheap (as someone has already mentioned).

By building this myself, I saved many coins on a shop-made rack, but the magnets still cost me around £30. The wood was an old shelf lying around in the garage. Mystery wood.


Steven


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## brianh (Dec 3, 2017)

Devon_Steven said:


> I used rectangular magnets in my rack a couple of years ago. Pics here:
> 
> https://www.flickr.com/gp/[email protected]/9EA92C
> 
> ...



Pics no worky.


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## Bill13 (Dec 3, 2017)

Work for me using google and Win10.


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## Devon_Steven (Dec 3, 2017)

Bill13 said:


> Work for me using google and Win10.


Okay for me too on various systems... Sorry you can't see.


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## erezj (Dec 3, 2017)

Did some reaserch for the rack I built (photos earlier in the thread)

I used L100X10X5mm N50 Neodymium Rare Earth magnets, it cost me at the time about $10 for the whole projects (2 continues lines)

for more technical details see the original post (unfortunately, I think the pictures were deleted)
http://www.kitchenknifeforums.com/showthread.php/31154-Magnetic-Knife-Rack-using-Rectangle-Magnets


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## brianh (Dec 3, 2017)

I can see pics now oddly enough. Thanks!


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