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View Full Version : Where to get 1/8" sheet mild steel laser/water jet cut?



HankMcSpank
02-02-2010, 12:39 AM
I need some small pieces 1/8" thick mild steel cut to a specific shape ...nothing particularly intricate, but a fairly important 9.5" radius in the design prohibits making them by hand...

http://img25.imageshack.us/img25/1685/partv.jpg (http://img25.imageshack.us/i/partv.jpg/)

I'm only looking for about 100pcs initially.

Anyone have any contacts that might be a good start? (I will provide a DXF file).

Vic66
02-02-2010, 08:03 PM
I use a company through work for laser cutting, maybe a bit far away for you but they've always done a good job for us and have done small jobs for me for cash in the past.

http://www.pritchard-sheetmetal.com

Robin Hewitt
03-02-2010, 11:25 AM
What is it then? :whistling:

http://www.parkersteel.co.uk

BillTodd
03-02-2010, 02:51 PM
http://www.pegpro.co.uk/

Although it looks to me a job easily handled on a rotary table in a mill.

irving2008
03-02-2010, 04:52 PM
radius is 9.5", its only 7mm wide, you'd need some sort of jig bolted to the table to hold a piece of 7mm x 55mm stock at ~9.5" from the table centre. Would need a big enough table to limit the overhang.

Robin Hewitt
03-02-2010, 06:05 PM
Wouldn't it bend like a banana as soon as he milled one cold rolled side off :heehee:

If he cut them from black he'd have to mill t'other side.

If he wants 100 the same then sheet seems the way to go.

John S
03-02-2010, 09:35 PM
I'm guessing 35 pence each to get laser cut, would you piss about making one of these for 35 pence ?

HankMcSpank
03-02-2010, 10:44 PM
Thanks for the links.

It's the steel core for a guitar pickup (of sorts) I'm protoyping....the 9.5" radius is what the more popular guitar necks have (ie if you were looking down the guitar neck from the pickup end)

Re 'pissing about' for 35 quid ...I guess that would depend on how much effort it takes the guy who sets up the laser machine (I'd have thought clamping one bit of sheet & loading loading one file with 100pcs crammed to fit into the sheet is the same as loading one file with one larger piece?) - now I'm no expert but I can't imagine it's much more than 20-30 minutes for someone that's a dab hand? If that's the case yeah, for cash in hand, I'd do it for 35!! (But when I asked, I didn't know it would be about 35p per piece!)

It's a shame we don't have a similar website to the yanks rfqwork.com at least then, the end operator can decide if he wants to punt for a 35p per piece job!

John S
04-02-2010, 12:36 AM
It's not just the 20 odd minutes, have you costed a sheet of steel lately ? Average full sheet laser costs between 250.000 and 400,000 and working flat out on production they can get thru 1000 gallons of liquid oxygen in 3 - 4 days.

BillTodd
04-02-2010, 12:17 PM
Wouldn't it bend like a banana as soon as he milled one cold rolled side off
Rolled steel will bend if you cut one of the rolled faces off (the stress in the remaining face will no longer be balanced out by the missing side) Mr McSpank would be milling off the edge only so, no serious bend problem.


I'm guessing 35 pence each to get laser cut, would you piss about making one of these for 35 pence ?

I wasn't suggesting "pissing about" making a 100 off on a mill. Hank only wants a couple to prototype his geetah pick-up

John S
04-02-2010, 01:27 PM
I wasn't suggesting "pissing about" making a 100 off on a mill. Hank only wants a couple to prototype his geetah pick-up

sorry but I read this in the first post, hence the reply.

I'm only looking for about 100pcs initially.

.

BillTodd
04-02-2010, 03:33 PM
sorry but I read this in the first post, hence the reply.

I'm only looking for about 100pcs initially.

.

:smile: So did I, but I've been following Hank's progress closely and realised he's not quite ready for mass production yet !

Ross77
04-02-2010, 07:52 PM
Hi Hank, building some hotrails or another variation on the sustainer? does the steal need to be 3.25mm thick? I'm sure the production ones are thiner, if so you could just use a guilotine and a good old file for prototyping.

HankMcSpank
04-02-2010, 08:38 PM
Hi Hank, building some hotrails or another variation on the sustainer? does the steal need to be 3.25mm thick? I'm sure the production ones are thiner, if so you could just use a guilotine and a good old file for prototyping.

This is for Sustainer MK XII! (for a non-blade version bedecked with twinkly lights have a look at a quick 'n dirty video I made - http://www.youtube.com/watch?v=xXB92cSQi8E be warned, the first 18 seconds is just me dicking about showing of the lovely blue LEDs! For a marginally better video of what the sustainer is all about here's another rough vid of mine - http://www.youtube.com/watch?v=106Se7AHknc (see the circuit on breadboard to the side!))

I relaise the production blade hotrails are much thinner, but remember this is to vibrate the string not pick up the vibrations...everything has to be beefed up - hence 3.2mm thick steel needed.

For the actual prototyping of this latest 'blade' version, yesterday I've ordered some modelmakers' 1/8" x 1/4" bright steel (I'd have prefered black steel, but they don't have it in a suitable size)....that works out at about 3.2mm x 6.34mm in new money, which happens to be pretty damn close for my bobbin 'blade' proto- so I've just Dremel'ed a length of 53.5mm's worth off the end!

For this latest blade type - here's a somewhat rough and ready test coil I wound around a DIY acrylic core (in turn cut from my DIY CNC!) with the steel I've just this minute cut (I'm still fine tuning the spec hence it not looking that refined yet)

http://img504.imageshack.us/img504/8711/blade1.jpg (http://img504.imageshack.us/i/blade1.jpg/)

The 100pcs of 'radiused' blade would be destined for my first 'batch' (wishful thinking that I might interest 100 people in buying one of thee puppies!)...so not exactly prototype, but not exactly mass production either!



This whole shebang reveals to me why we aren't a nation of inventors anymore - it's so darned expensive to get 'widgets' made (& I need widgets in spades...initially mainly to make the coil winder, but then I needed custom bobbins, hence making a CNC, then I needed some stuff turned so I bought a lathe)...alas, everyone wants more than 34p a piece!

Ross77
04-02-2010, 09:37 PM
Very nice work, I'll be your first customer.. I want one :smile:

Just an idea but could you make up the thickness with laminations of thinner steel like some transformer chassis's, That way you can find the optimum thickness. Also if it was thin enougth could it then be pressed?

If some one can make the former I'll happilly press you out as many as you need. 10 ton Hydraullic press with foot operated pneumatic pump is very quick.



I relaise the production blade hotrails are much thinner, but remember this is to vibrate the string not pick up the vibratiuons...everything has to be beefed up.


Fair point. dose the tuning not suffer from the pull tho?

HankMcSpank
04-02-2010, 09:59 PM
Very nice work, I'll be your first customer.. I want one :smile:



You'd be my second - on the strength of those ropey videos alone (which were for nothing more than showing my progress to a related Guitar forum) I've got an Italian chap who's taking a leap of faith & going to buy one off me (only because he's a niche requirement that can't be fulfiulled by existing commercial sustainer offerings!)

It's small beer at the moment (my hourly rate must be about 10p for what I'll be making vs the effort I've put in, but hey, from little acorns blah blah)





Just an idea but could you make up the thickness with laminations of thinner steel like some transformer chassis's, That way you can find the optimum thickness. Also if it was thin enougth could it then be pressed?



That's a reasonable proposal...and I'd considered it - but what's driving me towards 3.2mm more than anything is the availability of pre made Korean ABS 'blade' bobbins with an 1/8" 'blade' slot! (basicallly cutting bobbins on a dodgy homemade CNC takes forever...therefore if I'm ever to sell these in number I need a quicker way). It may well be that I can indeed go thinner, but additionally the blade needs a magnet on the bottom....& I need some amount of physicaly surface bottom area to attach the magnets to. (I don't have the luxury of normal pickup 'depth' to attach a hulking great ceramic magnet to as they do with blade pickups)




If some one can make the former I'll happilly press you out as many as you need. 10 ton Hydraullic press with foot operated pneumatic pump is very quick.



That's a fantastic offer - and I'd have to say a big high five to you all out there, for without one shadow of a doubt, this is the most helpful forum I've ever had the pleasure of being a meber of :clap:

As it goes, I don't know much about formers...how they're made., cost, limitations ...but it's something I'd pondered the other day & need to look into.




Fair point. dose the tuning not suffer from the pull tho?


Surprisingly no - because you're pulling & releasing in sympathy with the string's natural resonance.

Bye for now...

BillTodd
04-02-2010, 10:10 PM
but what's driving me towards 3.2mm more than anything is the availability of pre made 'blade' bobbins in korea with an 1/8" 'blade' slot! (basicallly cutting bobbins on a dodgy homemade CNC takes foreverA friend of mine has had some success with 3D printed bobbins in his audio transformers. He had the prototypes made at Shapeways (http://www.shapeways.com/)(from 3D models I made for him). Worth a look if you need complex shapes made in plastic as they only charge by weight and material (i.e. cheap-ish).

Bill

John S
04-02-2010, 11:28 PM
Hank, Check your PM.

Ross77
05-02-2010, 02:25 AM
I'm guessing John has a solution for you but........ Ive just had an idea for a quick fix........

Basically it involves using jigsaw with a fine blade and circle cuting attachment. If you can get the plate already in 55mm wide and say 500mm long then keep cutting blanks off as required. set the raduis to 9.5" to cut the radiused part and then square it off. quick buzz over a bench grinder wheel and job done. :dance:

P.S. how much do they cost?

HankMcSpank
07-02-2010, 05:25 PM
Hi Ross,

Thanks for the idea...it's a good 'un!

re having a solution...john was offering to get my part into a larger quote request he was submitting into a laser cutting Co ...but I need more testing with this blade version so will miss that particular landing slot (previous versions have use individual pole pieces)

Ross77
07-02-2010, 06:35 PM
Hi Hank
How much of a rush are you in, I'm sure I could make you batch of 10 or 20 next weekend. Ive just drawn the 240mm radius over 55mm width and its only 2mm. So with the band saw I can cut the rectangular blanks and then I'm thinking that with a radius jig mounted on the bench grinder the raduis can be ground, which would also give a nice finish as this will be the visible bit.

HankMcSpank
08-02-2010, 11:40 AM
Hi Ross,

I really appreciate your offer of help - but I wouldn't dream of putting anyone to that trouble!

As I explained to John via PM, I'm trying to stay one step ahead (so that when I arrive at a given point I already have the info I need!), so wrt pursuing the blade idea, I realised I'd need a quote to get them made properly. I don't actually need them made immenently, as I'm still very much in the 'proving' phase.

As it goes, after further (heavy) testing over the past 4-5 nights (using a rough 1/8" thick rectangular bit of mild steel) I've found that a 'blade' in a sustainer driver bobbin is sub par vs inividual guitar string 'pole' pieces. This is worrying ...I was just about to place an order for a few hundred blade bobbins from Korea! (presently I cut every bobbin I make on my CNC from acrylic - pain in th @rse!) ...I'm hoping it's just the variant of steel I bought (I wanted black steel ...but couldn't find any in a suitable 'hacksawable' size ....so I bought bright steel, which apparently - and I'm no steel expert - has more carbon in it?). If I place magnets at the bottom of the blade & then touch the other side (top) with a screwdriver, there isn't much magnetic pull - whereas when I do the same using pole pieces (mild steel grub screws) the top of each pole piece has a decent magnetic pull.


Two possible solutions...

1. Try a different grade of steel for the blade.

2. Crank up the strength of the magnets I'm attaching to the bottom of the blade (this would mean putting physically bigger magnet on there...and I don't have much room to do so)

So for now, I'm still, stuck in 'uncertain' land wrt blade type drivers.

I appreciate the offer of help though - many thanks.

ptjw7uk
08-02-2010, 06:55 PM
Not sure what you are ultimately trying to accomplish but putting a magnet one side of a steel bar will effectively short out the magnet, so I would not expect to get an awful lot of magnetism on the other side.
If you want the magnetism to pass through as it were they would need to be isolated a bit to channel the effect as in transformer laminations which are effectively insulated on one side such that the magnetic effect is channeled around the laminations and not leaking out the sides.
I think you need more design input.

Peter

Ross77
08-02-2010, 07:09 PM
I think Peter has beaten me too it but I was going to suggest using a thinner piece of steel, I dont know much about magnets but maybe a lower mass is required, as I said before the hot rails type of pick up use two thin strips, maybe this isnt a coincedence :tongue:

Maybe you can create a sandwich of plastic and steel to make up the 3mm width?

Why do you need a blade anyway? is it cosmetic or are there dead spots between the poles?

Anyway good luck

HankMcSpank
09-02-2010, 12:00 AM
Magnetism....it's well esoteric! (likewise Ross, I actually know very little about the science of magnetism...hence the trial & error aspect of making a good driver is my only option! I did find one magnetism forum, but didn't get much help there!)

OK, at the risk of straying well off all things CNC/Metalworking etc, for those that might not know, a guitar pickup typically has 'slugs' (mild steel 'cylinders') directly underneath each string with a ceramic magnet attached to the bottom. My (good) sustainer, emulates such a setup...the magnetism travels from the magnet attached to the bottom of the slug through the 'slug' & makes an appearance at the top (I don't yet have a gauss meter to measure the strength, but intend making my own gaussmeter with a PIC & a hall effect transistor soon).

The problem with a 'slug' design of sustainer is that a lot of guitars have different string spacings ....so for all this style performs well, if selling these eventually it's going to be a complete hassle establishing the guitar's string spacing & then having to make a custom bobbin to suit. (& Ross, since you ask....sting fade is not a problem when the string is bent between 'slugs')

The reason for wanting to now pursue a blade design is that it circumvents having to worry about the string spacing!

irving2008
09-02-2010, 11:32 PM
I see your logic Hank, but the blade wont generate the same magnetic field as a slug unless it was treated to localise the magnetic permeability. Otherwise the field lines from the magentic poles will travel horziontally through the steel and back round to the free pole. None of the field will escape the steel vertically and around the string other then a relatively small feild from the coil itself. The main purpose of the coil as I see it is to modulate the magnetic field from the slug/magnet to return energy to the string. But this can't happen if the field never leaves the blade. I'm no expert, but I did do some transformer design in the very distant past...

Robin Hewitt
09-02-2010, 11:44 PM
Only a suggestion, but how about glueing a load of 1/8" x 1/16" iron bars side by side and then cutting the part as slices off that. A sort of large format zebra strip.

The strings might not line up with any particular bar, but they will line up with some of them :naughty:

Edit: Typo :whistling:
Edit: So why isn't it showing the post as edited :eek:
Edit: How many goes do I get? Need answers :smile: .

irving2008
10-02-2010, 12:19 AM
Robin - it only shows as edited if it has been viewed before you changed it... back on topic now...

Ross77
10-02-2010, 01:28 AM
Or ultimatly you could just follow the pickup trend and offer only two sizes; Gibson (ish) spacing/raduis and a Fender (ish) spacing/radius, if there is no loss between the poles then I can see it matters.

I 've just looked at a few of my guitars and there dosnt seem to be a difference in pole spacing from bridge to neck pickup so its not an exact science anyway :wink: (I think they are only sold as neck or bridge based on the resistance/power output)