FEELER - STOCKLI / EMI / FAIRCHILD style Knobs

[baadc0de]

Hi Chaps,

I have thought about the DIY mold path, but as with every thing, its time to invest in how to do it, and its always more complicated than you first thought, but I have no doubt for the money id pay to get these knobs i could darn well work out how to do it.

must be sites on the tinternet that give info on mold making...

mmm...need to think it through before I buy any me thinks..

I copied a few dozen tabletop wargaming figures (with intricate, sub-milimeter detail) in epoxy resin using silicone (and similar) mold making agents. I'll look through my files, I know there is a specialist web shop in the UK that sells pretty much the best stuff there is to make molds with. Regarding material to cast in the mold, epoxy wouldn't do for most people I think, because it's light and might crack with a lot of usage. Though it is really cheap. I'm sure there are other durable, scratch resistant plastics too. There are tons of tutorials on youtube and the internet in general on how to make molds, how to make two-part molds (probably unnecessary here), how to make air escaping vents and how to pour copies. You could also have a negative created on your or someone else's cnc and cut out the requirement of having a positive first or making molds at all? Just a thought, so that stockli isn't involved at all and no copyrights or patents are infringed upon, fictional or otherwise. If you are handly with something like solidworks, which I think you are?

Cheers,
B.

 

[erikb1971]

wow.. making your own knobs.. that is hardcore DIY!

 

[zayance]

wow.. making your own knobs.. that is hardcore DIY!

Yeah could be, but everything is possible when you have the right tools.

Anyway, that is a big decision to make build or buy, and a lot of time and investment, at the end you'll be a knob company  , but that's what happens in our DIY head when we face some ridiculous prices, but there still have to be enough interest for that....

 

[user 10827]

Yes,

B, I think its THOMS you speak of, I spoke to them today and they were very helpful indeed.

Im going to have a play I think, the brass insert might be tricky, but i think i know here i could get them made as I live next to a machine shop, they might do it.

the chap at THOMS said you could tap the plastic, up to a limited degree of strength, but brass insert with grub would be better...

I'm going to give it some serious thought, because I've also thought id like to make molds for the smaller EMI style Ernest Turner meters...

Pete

 

[leadbreath]

hey pete,

if u serious about getting these knobs why not get them made in china? if there's no IP issues on these knobs im sure u could get these done and at a fraction of the cost.

mick

 

[baadc0de]

Adding something really obvious, but still ... when going with casting or custom manufacture, colours should be easily accessible.. some reds & blues... should look stellar!

 

[user 10827]

Hi chaps,

Making them is much more fun!

well China is a possible, but dealing with them is not easy from what I can make out.

I have a plethora of ideas,  I need to learn Solidworks or Rhino, maybe i can make a mold from Alu which i can CNC here, or Ill just make a resin mold and cast from that, but i need a real knob to do that, so the other option is i CNC an aluminium master knob from which i make the resin molds from...probably a better idea....any way I dont really know what im doing yet, but im going to try, if I crack the process there would be no end of things that can be made....

Pete

 

[mitsos]

learning new software sucks. Unless you want to wait a year to get this done, it's better to pay someone to model them for you. You'll get much faster/better results. Maybe Skylar would be able to help, or you can look for someone local so you can take part in the process.

Instead of making them in China, you could try a US mfg and still have the currency/exchange advantage.

 

[grantlack]

If I can get nice detailed dimensions I could very likely do the modeling in ProEngineer (solidworks alternative) and output g-code for cnc. The one issue you may see with cnc is some tool marking from stepped passes, a bit of smoothing for a master may be needed after the fact. Hope I can help, this is definitely up my alley!

EDIT: the only foreseeable cnc issues I can see are these-
If the circular portion at the base of the knob has a graded profile, this might be tough to do nicely on cnc without serious tooling marks. The etch in the pointer for paint may also be tough without a very fine bit. You're looking at a fair bit of rounding at the tip otherwise, which would be a candidate for revision by hand.

 

[wmtunate]

You guys know about this thread, right?:

http://www.groupdiy.com/index.php?topic=32853.0

Skylar apparently made up a solidworks model already.

 

[grantlack]

You guys know about this thread, right?:

http://www.groupdiy.com/index.php?topic=32853.0

Skylar apparently made up a solidworks model already.

Well I guess that saves me some work then! 

 

[user 10827]

Hey Chaps, all great info.

Well ive messaged Skylar to see if he still has the files and would allow the usage of them.

But If not grant I'll be intouch! I have a friend also that is very good with google sketch up and that can output STL files too so thats an option..

You are also right about the finishing on the knob, I think some hand finishin by hand would be needed. Al thought with very fine pass and using a rounded bit i believe you can get very a smooth finsih, which we could then sand and buff.

the other option is we make an inverse of the knob out of Aluminium, but in two parts which fit perfectly together, kind of like doing injection molding, but is uspect that might be trickier..much much easier to make resin molds from either a alu or real knob..

Cookin on gas!

Pete

 

[barclaycon]

What absolute nonsense. £15 for a control knob!
Stupid. Ridiculous.
And anyone that pays that for a knob is stupid too.

Not having a go at you Chris - you just want some nice looking control knobs right ?

But charging those kind of prices for what is effectively a little piece of plastic with a brass insert....
they should be ashamed of themselves.

Maybe they got too used to ripping off tourists !

 

[user 10827]

well that was fun, just worked out how to use Rhino3D, its not perfect just yet but not looking too bad for a 1st bash....I've a real one turning up soon so I can take proper measurements as this was just from a picture,

but once its ready I can generate some Gcode from this and CNC a master...

Pete

 

[baadc0de]

Looking good!

 

[user 10827]

think i need to optimise my tool paths, CNC says 186 hours! LMAO...that's easy....but any way i was just checking Cut3D could open the Rhino file and it does...

 

[shabtek]

is that estimate based on the 'size' at the bottom (23x62x19")
that is a big knob--or will it be geared down?

 

[user 10827]

Yip! I spotted my mistake there too, Ive scaled it down now and its only an hour or so, depending on the finish quality it can go up by a another hour or so, but that's OK.

I've added the skirt now too, the real knob should be turning up tomorrow so i can make to the proper dimensions,

I've nooo idea if this will turn out to be any good, fingers crossed, also we should move this thread into the LAB I think...

 

[API]

I have unlimted access to a real Fairchild 670 all weekend so I could prop. do some measurments as well if needed.

I know a guy in the Uk that recently that moulded a PYE knob that he was missing.
From what I know he made a plastic cast from a real knob and the moulded it in that, looked amazing.
Not sure what kind of materials he used though but it is possible to do with good results.

 

[user 10827]

Hi Dennis,

that would be great if you could, as I think there are two sizes on the 670, a larger one on the metering and a mini version on the Time Constants, so if its easy a quick measure up would be fab..

I have one good knob coming but I don't think Andy will be too happy with me if I poor resin all over it...

Pete