I need to tap into your collective engineering mindsets!
Ok, for those who are following my spare time exploits...I'm now faced with making my own pole pieces (nickel plating kit is on its way) for a giuitar pickup type device (on account the pieces I need aren't exist to buy pre-made in the length I require)
So I'm faced with cutting 4mm diameter steel - into 5mm lengths (last we spoke I was going to be using 5mm dia steel rod, but I reckon can get away with 4mm now)
To actually cut the pole pieces to length, I'm toying with mounting my lightweight Proxxon rotary tool horizontally to my CNC's z axis & then just clamping the 4mm steel rod to my table - hey presto, I can easily knock up some G-code to cut six 5mm (exact!) lengths of steel!
The other option is to manually hover over my mini lathe & part the pieces off manually (not so appealing)
ok, if I go the rotary tool route ....it leaves a rougher edge so I need to deburr on of the edges at least (so it'll feed into the somewhat tight fit 4mm hole in the coil bobbin). The thing is 5mm lengths of steel are a nightmare to try and put into a chuck....so what I now think I need is a bespoke '4mm pole piece holder - deburring for the use of' tool!
To this end - any ideas?
My first thought is a very simple 'holder/collet' type arrangment made out of steel - I affix a rare earth magnet at the rear end of the collet - this will attract/pull the steel 4mm pole piece into the hole ....my collet will have a 4.2mm diameter - meaning the collet has to clamp down about 0.2mm to hold the piece. The holder - being longer & easier to hold - can then be inserted into a lathe spindle collet etc & then the pole piece chamfered.
Never having made a collet (and Google surprisingly has scant info) I'm wondering how to get those 'splits' at the end of one - they're a very fine dlot (dremel cutting disc at 0.8mm diameter springs to mind) - I don't need whole a lot accuracy ...the main driver here is being able to quickly mount/dismout through 6 pole pieces to debur them quickly.
Last edited by HankMcSpank; 08-03-2010 at 04:53 PM.
Just hack 'em in with a hacksaw. That is standard procedure for making quickie grippers. As long as the slots are somewhere near, they will be ok.
Life is too short for playing about with tolerances on something like that. Just make sure you deburr the inside and outside before use.
How about putting the rod into a pillar drill/ Mill, clamp a cutting disk to the bed at the desired angle and bring the rods down to the disc?If the nagging gets really bad......Get a bigger shed:naughty:
you can use a similar idea with a mini drill cutting disc clamped in its holder in the vice, and move the mill bed to the desired depth for the cuts?If the nagging gets really bad......Get a bigger shed:naughty:
Well, if you want suggestions, I think you need to make a jig.
Off the top of my head...
A lever, sprung up at one end against a stop
At the end of the lever, a groove to hold the stock. Cut paralel to the lever pivot.
A second lever, on the same pivot above that, so when you push down it grips the stock against the spring and then forces it down.
Then add a thin angle grinder blade that comes up through the middle of the lever and slices through the stock. The stock being supported on both sides of the cut.
Lift the top lever slightly beyond gripping and the depth stop goes with it so you can eject then advance.
Thanks guys - bogstandard, yep, I agree lifes to short...I don't need a whole lot of accuracy, but never having made such a beast was just curious as to how they did it! 2e0poz ....a couple of nice tips there - I especially like the first one :-)
Robin...I'm having diffs visualizing what you're suggesting. Going this route, then cutting from stock would obviously be quicker per piece ...but wouldn't the pieces still need deburring? (it's this aspect that's the real pain in the backside)
This is assuming your pivots are tight. If not tight then you might need to joggle it side to side after cutting to get the burr free face.
You could probably remove any heat bluing chemically if it worried you, or add splash guards so you could cut it wet.
This could be automated fairly easily with cams :naughty:
The reason i suggested what i did was that had to cut down the 30mm and 20mm rails for my build. I did this but putting the rod in the lathe and used an angle grinder to shorten and face off the ends. This worked great so should not see why it would not work in a mill/ vertical drill to do the same on smaller diameter rod. The fact that the abrasive disc would pick off the burs from the edges should prove quite well and if you use a pecking motion then should be no reason why should end up with blueing (gaps btween pecks)? my second idea was to use the very small mini drill cutting discs (they do not last long)If the nagging gets really bad......Get a bigger shed:naughty:
Another option for cutting would be to use a shear (or large bolt croppers) if your going to clean up the ends? cut oversize and grind back to appropriate sizeIf the nagging gets really bad......Get a bigger shed:naughty:
If the job is not already done.....part them off in your lathe.
Go in 1mm, back out and de burr the edges. Then back in to complete the parting.
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