Build of a permanent magnetic chuck / base / vise. Part III: finale 

Thank you! 🙂

Thank you!

Thank you!😊

Mulțumesc 🙂

All right! Go for it! And if you have any questions, don't hesitate to ask.

The plans are very simple. It is a matter of buying enough magnets (in my case 170 pieces ø6 mm by 8 mm), and measuring the diameter and height accurately. Then make a slab of aluminum that is only a few hundredths of a mm thicker than that height and with the correct number of precise holes with the desired spacing (for me 2 mm). Then two aluminum slabs with the same holes in which you glue the steel cylinders. The dimensions and flatness must be very precise, and the eccentricity of the scotch yoke must accurately match the needed replacement of the magnets ( half of the magnets diameter plus half the gap, so for me exactly 4 mm). For the rest you are actually free to choose the dimension at will. If you have a design in mind and have questions, feel free to ask.

Great, I will keep you posted with my progress. Thanks again Tom

I didn't mill the magnets. Neodymium is too brittle and hard to mill. Besides, when one removes the thin nickel skin the magnets would corrode very quickly. I only milled all those steel cylinders at both sides of the outer slabs

didn't you do a skim cut of the neo magnet surface? @@Michel-Uphoff

@@en2oh No. There is no need for that.

Thank you! No, no plans available, but the design is very simple. Read the comments and my answers here and, together with the video's I think you will get a good impression of what's important in this build. And if you have questions, juist ask.

If it is indeed stainless (a magnet won't stick on it at all, so it has a very low magnetic permeability), and you have the tools to machine that stainless steel, it is even better than aluminium. Much more wear resistant, stronger material.

@@Michel-Uphoff thank you for response.Iwill make one,ipromise.ihave one small lathe and ilove it alot,so Iwill make one small magnet chuck exactly the same system what you made. Mit freundlichen Grüßen Sina 🇦🇹

OK! Exited so see the results. Please keep us posted.

Stainless is a pain to drill :)

Don't be sorry, I like it when people are interested in my builds. All metric here on the other side of the pond. The middle plate with the magnets is on average 0.03 mm thicker than the height of the magnets. My magnets are 8.03 to 8.05 mm high and the plate is 8.07 mm thick. This is important, you don't want the magnets rubbing against the steel cylinders with any force. Now that they can stay just below the surface, the magnets barely touch the steel cylinders that pull the magnets more or less evenly in both directions. This means there will be hardly any wear on the magnets, which is important because the protective layer of nickel is thin and neodymium corrodes very quickly. That is also why the magnets must be able to move freely up and down in the plate so that they can 'settle'. So I made the holes 0.02 (1 thou) mm wider than the diameter of the magnets. The top and bottom plate are 10 mm thick (slightly thicker than 3/8"), and so is the height of the cylinders.

If I heard it correctly in the video your magnets are 1.5 mm apart. They don’t appear to be that far apart. I am contemplating making mine 3 mm? What do you think? Thanks for being patient.

1.5 mm was for the prototyping. For the final build I used 2 mm. As you can see in the second part, the spacing is important when very thin steel work pieces are to be sucked on the plate. So if you intend to do so, make the spacing as small as possible. Keep in mind however, that a small spacing weakens the strength of all slabs. The middle slab has to survive a considerable tension / compression force lengthwise when moved by the Scotch Yoke. 3 mm could be OK, but that would reduce the number of magnets per surface area roughly 20% compared to my design. It all depends on the dimensions of the magnets you are going to use. And of course the quality, you don't want NdFeB N30 of 35 magnets. Prefer the more expensive N50 or N52 grades. They pull roughly 60% harder than the cheap ones.

I am looking at N52 right now Thanks

@@Michel-Uphoff what if you arrange the magnets in a honeycomb pattern? This way the distance will be distributed more evenly and densely and you will probably get even more magnetic force from the vice. I don’t know, I don’t understand physics well, I rely on my intuition, which, by the way, is sometimes wrong :) By the way, great video! I like your channel and right now I subscribed to it.

Have you watched the previous videos? The part about the magnetic permeability of different metals is particularly important. You don't tell what material the plates are made of. Aluminum I hope. Steel as a top and bottom plate actually short-circuits the magnetic field, which is of no use to you. Like me, you will have to use aluminum with steel rods inside to "open and close" the magnetic field. Brass, copper or good quality stainless steel can also be used for the three layers. Are you sure the alignment of the magnets and cylinders is spot-on? A deviation of one millimeter is enough to ruin the pulling power. Furthermore, I think a mutual distance of 6 mm is a bit much. Approximately half of the magnets can then be accommodated per unit area, and so the clamp also provides half of the pulling force. What grade of neodymium did you use? If that is a low grade, such as 36 instead of the 52 I use, then another 50% of the pulling force is lost, leaving you with 25% of the force I established.

@@Michel-Uphoff Yes, I watched the whole video; Plates - aluminum; 6 mm between rows is not enough, this is my mistake; The magnets turned out to be N42; The holes are aligned and made using CNC.

So, if the magnets are aligned properly, you should reach a pulling force of about 0.75 (grade difference) * 0.5 (number of magnets per surface area) = 37.5% of the holding force I reached, maybe somewhat less because your magnets are longer. Still a considerable force however. The alignment is precise, and the magnets hoover just (not more than a few hundredths of a mm) under/above the steel cylinders? All six main surfaces are really flat? You'r sure that you have used alternating plus and minus poles as in the previous videos is explained?

If you don't count the hours of work, it's cheaper. If you count them in, o hell no, this is way more expensive! But I don't think this design, with a magnetic bottom, is for sale.

sweat equity! BRILLIANT! As a retired person, I can get a pretty good rate when working for myself! 😀@@Michel-Uphoff

Thank you! 🤗

Sorry, I don't understand your question. Could you elaborate on it?

time 23/ 41 about in video hou make surface on a blade. what disk you have in a mill chuck??? Very interesting!! Thanks...sorry for my english...

@@kostasmarkakis2596 No need to apologise. I'm sure many anglophones hardly understand a word Greek. I guess you do very well, judging by your name. And if I am correct you very well know what an anglophone is. That's a "vacuum brazed diamond grinding cup wheel". If you google these words you will find many examples.

Thank you very much!!!

Hi Paul, No problems with magnetic swarf and my scales. I just wipe them clean when there is too much swarf on them. I know the 'secret' of demagnetization and have a small but effective demagnetizer (just a W shaped core with one coil, creating an alternating magnetic field, effectively 'wiping' the magnetization). You can see it somewhere in this video. In theory every force deforms a work piece, but most times the work pieces wil be flat and that shape wil benefit from the pull of the magnets, keeping it flat while milling or grinding.

@@Michel-Uphoff I think his way of visualizing the fields is very clarifying.