Making magnetic blocks

[Ueee]

Hi all,
Over the last week or so i have been working at some magnetic blocks for the grinder. A large one to make into a V block and a couple of rectangular ones. I have filmed a lot of it and posted 3 vids so far, in the guise of a "how to" type vid, stuff ups and all (and we haven't even gotten to the good ones yet:no:)

The first one is here https://www.youtube.com/watch?v=4JbyxIp4xEs&feature=c4-overview&list=UUPacYhev35p4rkKjPAwVO8Q
If that doesn't bore you to sleep the rest should be easy to find from there.

Some pics as well, its hard to remember to take stills when you are filming, so there are only a few. I spent the arvo grinding the smaller blocks square and making a proper curved thingy for the front of my gauge stand. In the next few days we will see just how square my cheap screwless vice is!

So much for being in painting mode......

Cheers,
Ew

[shedhappens]

Nice work as usual Ueee :2tsup:

Try a page out of a phone book between the mag chuck and the job, it makes it easier to remove
the job and protects the bottom of the job and the mag chuck from scratches :D

[Stustoys]

Hi Ewan,
Are some of blocks made with Alum for the gaps?

Looks great.

Did you solder them with a flame or oven?

Stuart

[RayG]

Nice work Ewan,

The only thing I would do different is drill for the through pins before soldering, I used threaded brass rod and tightened a couple of times while it was in the oven.

To thin the solder paste you can use metho, if you want a really thin layer, you could make a thin slurry and brush on.

I love that you are now surface grinding everthing... :)

Regards
Ray

[Ueee]

Why do i get the feeling the phone book in the shed might start getting thinner soon:rolleyes: Thanks John, i will try that.

Stuart, yes the small blocks are ally, they were just epoxied together, was a nightmare in the end as the epoxy didn't hold very well at all. I wanted to use urethane glue but my bottle had gone crunchy......Of course you cannot solder ally with lead/tin solder.
The big block was just done with a flame, on the gas camping stove actually. I'd loved to have used an oven but as i don't have one yet.....still looking though!

Ray, it probably would have been better for the little blocks in the end, but with the big one i don't see a problem with drilling then post solder, its just the length of drill bit required that has stopped me at this point. There is one on its way. I was going to make an excuse about not having brass threaded rod but of course i could have easily threaded the ends of the rod i used. That way the solder should have flowed along the rods too, really holding it all together.

My mind still boggles at just how accurate the grinder is....its alarming when you grind .001" of a milled surface and there are still marks from the cutter there. It really is on another level to the mill and lath.
All food for thought......

Cheers,
Ew

[Brobdingnagian]

Why do i get the feeling the phone book in the shed might start getting thinner soon:rolleyes: Thanks John, i will try that.

Stuart, yes the small blocks are ally, they were just epoxied together, was a nightmare in the end as the epoxy didn't hold very well at all. I wanted to use urethane glue but my bottle had gone crunchy......Of course you cannot solder ally with lead/tin solder.
The big block was just done with a flame, on the gas camping stove actually. I'd loved to have used an oven but as i don't have one yet.....still looking though!

Ray, it probably would have been better for the little blocks in the end, but with the big one i don't see a problem with drilling then post solder, its just the length of drill bit required that has stopped me at this point. There is one on its way. I was going to make an excuse about not having brass threaded rod but of course i could have easily threaded the ends of the rod i used. That way the solder should have flowed along the rods too, really holding it all together.

My mind still boggles at just how accurate the grinder is....its alarming when you grind .001" of a milled surface and there are still marks from the cutter there. It really is on another level to the mill and lath.
All food for thought......

Cheers,
Ew

Good thing about the phone book is that you get an automatic restock every year....

Loving the work Ewan, I would normally give myself a little extra going from a machined surface to a ground surface, 25µm ~(13 minimum passes) would be the minimum that I would want to work with per a side, with a workpiece say 100x100mm.

Another tip on the final debur is to use a course whetstone to deburr, something about a 320grit (~50µm grains) works well.

Pls more vids....

-J

[Ueee]

Good thing about the phone book is that you get an automatic restock every year....

Loving the work Ewan, I would normally give myself a little extra going from a machined surface to a ground surface, 25µm ~(13 minimum passes) would be the minimum that I would want to work with per a side, with a workpiece say 100x100mm.

Another tip on the final debur is to use a course whetstone to deburr, something about a 320grit (~50µm grains) works well.

Pls more vids....

-J

Yeah the .005" (the .003" block must have not been seated properly when milled) got me in trouble with the ally blocks as the ally was only .122" not 1/8". If it wasn't going to solder them i probably would have given myself more....hang one, 25um, thats only .001"per side? Do you mean .010"/.25mm?

There is more vids, just need to cut out all the bits were i go silent in deep thought. I'll definitely be doing some on making a 450 x 150 sine plate for my new chuck.
I like vids of other guys working "in full" and not just edited together snippets. They always give an incite into other ways to do things.

Ew

[morrisman]

Looking forward to the other parts of your lesson ........... interesting stuff :2tsup:

[Brobdingnagian]

Yeah the .005" (the .003" block must have not been seated properly when milled) got me in trouble with the ally blocks as the ally was only .122" not 1/8". If it wasn't going to solder them i probably would have given myself more....hang one, 25um, thats only .001"per side? Do you mean .010"/.25mm?

There is more vids, just need to cut out all the bits were i go silent in deep thought. I'll definitely be doing some on making a 450 x 150 sine plate for my new chuck.
I like vids of other guys working "in full" and not just edited together snippets. They always give an incite into other ways to do things.

Ew


Sorry Ewan I should clarify, 25µm is the absolute minimum I would need per a side. I prefer to have 50-150µm per side total much more than that It's back to the mill, I would normally take 60% off the first side, 30% opposite and 10% on the flip flop, This also lets me check my wheel wear/dressing and creep up on final dimensions and also check for distortions. My mantra is "more than 1/2 a mil(mm) back to the mill"

Keith Fenner does some great cuts in his videos where know know he has hit the "what do the ^*&! do I do now" moments. But he comes back and works through the solution.

If I had a go pro or something I would do a few videos, but as it stands having a camera where it needs to be is harder than it sounds.

-J

[Stustoys]

they were just epoxied together, was a nightmare in the end as the epoxy didn't hold very well at all.

Did you use interface membrane?:D


but with the big one i don't see a problem with drilling then post solder,
I do, solder under pressure cold flows. Now it will depend how thick and even the solder joints are and how much pressure you put on them......Now I doubt its going to move much... but I wouldnt really know....and you're going to be grumpy if it moves at all......just remember you heard it here first ;).

Is there really a need to pin it after soldering? just how high would you have to drop it from to break one of those joints?

Stuart

[Machtool]

Did you use interface membrane?
Ewan might not get that reference. Its a fly wire spacer to get a good bond thinkness. Which improves shear strenght. Its a highly scienintific excersive which involves a trip to Bunnings with a micromiter in hand.

Phil.

[Ueee]

Ah, and here was me reaching for the wife's sewing interface:D Next time i'm in bunnies i'll go mic in hand!

Stu, your super power has let you down! It wouldn't bother me a bit if the big block moved a little whilst drilling. But only if it moved a little. The finish on it may be reflecting nicely but its not ground. I can only thank Michael G and a new box of SEKR inserts for that. (ok and maybe Mlle) And if you wouldn't mind making a block up of your own and dropping it then i'll know whether i need to pin it or not:D

Ew

[simonl]

Well done Ueee.

This is quite an interesting thread. I have a couple of questions if I may,

The magnets, are they just rectangular neodymium of say N32 or N40 etc?
There is mention of both epoxy glue and soldering. Specifically, how does that work? Do you put them in the oven AFTER epoxying to melt the solder?
When you machine them flat/square etc, how do the magnets machine? I would have thought they would shatter.

Thanks,

Simon

[Michael G]

The magnets are in the magnetic chuck on the grinder Simon - the things that Ewan has made are the magnetic versions of parallels.
By alternating layers of magnetic and non-magnetic materials the blocks can transfer the magnetic holding force. From what I understand the epoxy is because Ewan used Aluminium for one of the blocks which is difficult to solder so instead used the glue.

At one place we did grind ferrite transformer cores, but it required diamond wheels, lots of coolant and very small feeds. I imagine a ceramic magnet would need the same

Michael

[Ueee]

Hi Simon,
They are not magnets.....they are just steel and brass/ally plates. The ally ones are epoxied as you can't soft solder ally (except maybe with some AgSn solders?) The brass one is soldered.
If you watch the first vid, the one i linked above, i give a brief (and probably poor) description of how a mag chuck and the mag blocks work. The blocks are designed to extend the N and S poles of the mag chuck up, without the poles "shorting" each other (i'm sure there are technical terms for that) so that a workpiece can sit on the blocks and be on both N and S poles.

Ew

Edit, i'm too slow Michael!

[Stustoys]

oops, thanks Phil,


Stu, your super power has let you down
Not yet they haven't. Its not drilling the holes. It's the clamping. Now remembering in this application* this is a theory. Once you pein the pins you will putting pressure on the solder, now it may start to cold flow, but thats not something that happens fast. So you may pin it, grind it, and then find it moves.......... I may also be talking out my ... :D

I'd only drop the damn thing on my foot :rolleyes:

Stuart

*the application I am aware of is not soldering wire before it is swaged or clamped.

p.s. Simon they are magnetic tranfer blocks, not magnetic themselves.

p.p.s damn you guys type fast

[Ueee]

Ok, got you now Stu.

I found with the little ones peining was just a pain in the ar5e. One of the blocks is peined, one is just loctited in place. With the big one i was even thinking of adding more solder and just soldering the pins in place. I think now i really should have drilled first......:doh: Next time.

Ew

[thorens]

Ok, got you now Stu.

I found with the little ones peining was just a pain in the ar5e. One of the blocks is peined, one is just loctited in place. With the big one i was even thinking of adding more solder and just soldering the pins in place. I think now i really should have drilled first......:doh: Next time.

Ew

Hi Ewan.
very nice job . you seem to make the most out of the new grinder :) , i take my hat off to you .
what kind of glue did you use to stack those magnets ?
cheers
Peter

[simonl]

OK. So they are flux capacitors :doh: No just kidding, I understand now. If I had have just watched the video it would have negated the need for me to ask! I was at work and our bandwidth can be painful at times so I didn't bother putting myself through the anguish!

Simon

[wheelinround]

Like it off to view video's :2tsup:

[Ueee]

Simon, yep sure are, but should i go back or forwards in time first??

Peter, the glue on the small blocks was epoxy, but it did not work so well. I would have liked to try polyurethane, but my bottle had gone hard. Poly glue goes off with moisture so it has a pretty short shelf life once opened.

Here are the links to vids 2, 3 and 4.

2 https://www.youtube.com/watch?v=SyTDZzYuNUs
3 https://www.youtube.com/watch?v=xsdXM5n_n-k
4 https://www.youtube.com/watch?v=MKafORsmZtk

Next video will be on to the small blocks.

Cheers,
Ew

Edit, how come sometimes the video links come up with the name of the vid and sometimes just the address? I know using the insert video button adds an in forum viewer.

[Brobdingnagian]

Simon, yep sure are, but should i go back or forwards in time first??

Peter, the glue on the small blocks was epoxy, but it did not work so well. I would have liked to try polyurethane, but my bottle had gone hard. Poly glue goes off with moisture so it has a pretty short shelf life once opened.

Here are the links to vids 2, 3 and 4.

2 https://www.youtube.com/watch?v=SyTDZzYuNUs
3 https://www.youtube.com/watch?v=xsdXM5n_n-k
4 https://www.youtube.com/watch?v=MKafORsmZtk

Next video will be on to the small blocks.

Cheers,
Ew

Edit, how come sometimes the video links come up with the name of the vid and sometimes just the address? I know using the insert video button adds an in forum viewer.


I like the vids and the block Ewan; it is always nice to watch someone else work :P

What is the chance you might want make up one of the 90 degree rotation adapter plates(pitch changer)? I know Ray has been wanting to taper some spring steel for a zero set backsaw for a while now and we need a very fine pitch chuck for that. I'm happy to workshop the idea with you, maybe we can get good dual(ing) build thread going if your interested?

-J

[morrisman]

Hi Ewan

Great videos . I noticed you didnt grind the brass pieces , they wont stick to the mag chuck :p THE 8 THOU OVER LENGTH MAY BE DUE TO THE ROUGHER BRASS

[Theberylbloke]

Hi Ewan,

Nice blocks.

Aluminium can be soldered. I have seen it done, going back 35 to 40 years, as an apprentice.

Aluminium cables used for distributing low voltage in underground sub-divisions required the process. In cross section, the three phases were shaped like 1/3 of a pie and the neutral was a tube around the outside. Everything insulated with oil/greased paper. The connection to the round neutral was a short tube of tinned metal that was soldered around the outside of the aluminium. The special solder used was called "friction solder" I don't know what was in it.

The system was not the greatest as the soldering often dried out the oil/grease from the paper and the whole thing would short out some time after being put into service. This is not the greatest recommendation even though I doubt you will have 240V through your blocks. Mind you, could be highly exciting if you try and we definitely want to see the video on that!

Cheers

The Beryl Bloke

[Ueee]

The funny thing about the 240v comment is that for a few seconds (and no more) I actually thought of using the welder to heat the blocks up. Clamp on one end, stick a big rod to the other.......and hope the rod didn't act like a fuse before the block was hot enough to melt the solder.......hell if it got hot enough I could have just fused the whole lot together......

Ew