FEELER - STOCKLI / EMI / FAIRCHILD style Knobs

just a small update, this is what I should be making the model/master from! not aluminum...what a knob! 

http://www.trycut.co.uk/

Some one is selling a box containing 4 of these beloved knobs...scroll down a bit...

http://www.groupdiy.com/index.php?topic=35283.0

Could some one move this thread to the LAB please? thank you.

I've just knocked up the other small flute knob on the TG limiters..so I've some machinable wax coming, new cutters plus some Silicon / plastic coming...going to give this a serious bash..if for nothing else for fun..

I bought hundreds of red and gray(bluish actiually) knobs directly from Chandler for $15 each, no quantity discount.  They had them in stock in both 1/4" and 1/8" shaft.  No black.
I would be interested in about 300 black knobs if they are the correct shape.
Mike 

Hi Mike, that's interesting indeed, still quite a bit of money, even with the exchange its around £10gbp.

What is even more interesting was my prices were based on 50 - 100 quantity, so hence dear price, they must buy them in the mega ton and I wonder if they even buy stocklis, maybe making them in china..

In the next few weeks I should know whether I'm able to produce any or not, I am planning on making Black/Grey/Red first..

Only slight issue im having is to hunting down the brass inserts with grub screw, it must be a manufactured item already...so I've got to do some phoning this week..

Best
Pete

Here's a crazy thought I just had (feel free to ignore me!)

If obtaining and fitting/securing the brass inserts is expensive, how about this- design the knob as a 'cap' that slips over the top of a cheap, commonly available knob that can be bought by the thousand. Glue it on, voila!

Crazy or genius?

Hey Mike,

Well any idea is a good Idea, And i see where you coming from, but fixing it to the smaller knob would still need a screw of some type, of course i could tap the plastic and have no brass insert at all, but thats not as good as a brass insert.

There has to be some thing already, its in almost every knob ever made, if you Google brass insert there are loads of very similar things but not quite what im after, so I plan to ring them, i'm hoping they will say ahh you need an XYZ and that will be that.

Cookin!

Grand Master Audio said:

Hey Mike,

Well any idea is a good Idea, And i see where you coming from, but fixing it to the smaller knob would still need a screw of some type, of course i could tap the plastic and have no brass insert at all, but thats not as good as a brass insert.

Click to expand...

Glue it on, old chap! Good old-fashioned superglue. Job done! Anyway I won't push the idea too much, it's just an off-the-cuff idea...

Epoxy would be better IMHO beside Superglue, well if you go that route...

I have not read the whole thread so sorry if this has been suggested before...
Anyone searched alibaba.com ??
Might be that the factory is linked to that site as well. Only downside when ordering in China is the min. order quantity.
Between 1000 and 5000 pieces or so. Price should be a bargain though, especially when compared to the Monaco dealer.

Another thing: what would it cost to have a mold made in China? Just for 1 knob? Basically you just can ask ANY knob manufacturer on Alibaba.com

The General Radio decade resistors go for as little as $20 on ebay, I would just get a knob off one of those and pull a mold from it. There's no real need for metal dies or machining. Use silicone for the mold, and cast the knobs from low viscosity casting plastic, to avoid bubbles.

Brass inserts could just be some 1/4" ID thick wall tubing, machine some notches around it for gripping power. You could use a drill press and file as a lathe to do this, or even a dremel cutting tool, doesn't need to be pretty.

Cast the insert into the knob, then drill and tap for the grub screw.

Hi Chaps,

Hi Ed, All though in this circumstance there is no real need to machine as I have a real knob here, but I've been looking for a reason to do some 3D machining (other than engraving) with my CNC and here it is.
With machinable wax it's easy, I've got the plastics covered, I've done my home work here so that should be cool.

to Radiance also, If I crack the above process pretty much any thing i can draw in 3D i could potentially make, not just for audio DIY but for my other hobbies too, so im dead excited..

So what exactly is 1/4" ID thick wall tubing? ID?

Pete

Grand Master Audio said:

So what exactly is 1/4" ID thick wall tubing? ID?

Pete

Click to expand...

Inner/interior/insert synonymous I-word at your leisure diameter.

gotcha...kinda obvious really! 

latest revision up-to-date dimensions..

I think they are made in China.  Their minimum run for black was 1000, and they still wanted $15 each.

Once you talk about kludging knobs together or cutting tubular stock your manufacturing costs go way up.  In quantity over 1000 a slip-on would be a few pence less than an actual bushing/setscrew knob.

That solidworks knob looks very sharp.  The originals and the Chandler knobs are a bit smoother top to sides.  I finished a TG12345 refurb and the desk out of the shop and in constant use now, but I will try to get a pic of the old and new knobs as reference.

Mike
PS: one other difference is that the originals have two set screws and the new have only one.  One is certainly enough to hold.

Hi Mike,

you certainly have a keen eye, I've been trying to get a softer edge on the top to side on the back piece, but i cant seem to get it right as it goes around the corner, I only started learning this 3D stuff the other day, so im working on that bit..but I will try to do it for sure.

Love to see some pics, the new one I have here has one set screw in the center of the back, Ive seen others that come in from the right, this must be what you are talking about with the two set screws.

ah! i've just thought of a way to do the softer edge...weird how your brain works on stuff in the background..

Pete

Doing a 3-piece variant a la Marconi with the clear skirt on these would be kinda rad, but could be tough to pull off with the pointer. I've had an itch to try some led refraction if the right knob comes on the scene, I do my bed work in the dark  ;D

EDIT: BEST, not bed.  but i suppose that works too.  :

Hey Mike, soft edge revision...I'm using a extra long reach .5mm end mill for finishing, It's looking pretty good...

Very Nice! I think the soft edges are all around tough, looking at some pics. Anwyay i'm very curious on the progress of this one, keep them coming...