batwing knobs

[mike hadley]

As I am in the process of making a set of knobs for my Philharmonic I thought to share this,

apparently there were some early sets with all wooden knobs, after seeing a photo of a set (thanks Kent) I thought that I would have five wooden knobs with two batwing's like the ones that are often seen on Philharmonic radios,

a rough sketch was made, this is taken from my aw15 selector knob minus the pointer,

please be aware that the dimensions are only approximate,

the next step is to put a piece of 20mm brass bar into the lathe and rough out the main body,

the bar is drilled with a 1/4" hole 1/2" deep for the pot shaft, I decided to turn the job with the spindle hole outward to allow all turning to be finished before parting off.

Apologies for the poorly focused photo.

After parting off, the knob bodies are then polished to remove most of the turning marks, this is important as they would show in the finished item.

Looking down at the knob with the taper end down, two holes are then drilled, a 2.4mm tapping hole at 12o'clock and a 3mm hole 3/16" deep at 3 o'clock, this is just shy of breaking through to the spindle hole,

tapping hole m3 for fixing grub screw,

photo showing both tapped and blind holes,

the handles are then cut out from 1/8" brass flat stock as per the sketch, shaped and lightly sanded to remove file marks, these are then turned in the lathe to have a 3mm stub 1/8" long

the knob body then has a flat filed over the blind hole, this gives an area just big enough to let the handle sit flush on the knob,

the stub that is turned on the knob handle acts as a rivet, this fits tightly in the hole, this is then tapped home with a soft face hammer, securing the parts together for the next step, brazing.

I am using "easy" grade solder, this melts at around 1300f this needs borax flux and a gas torch,

this is what the parts look like after a pickle in acid (10% sulfuric) to clean off the spent flux and fire scale,

and finally after they have been aged in liver of sulfur,

I hope this is of some use, Kent tells me that there are some repo parts but one day I'm sure these will also run out,

Thanks for looking.

Mike

[Scott Seickel]

Looks great.  No worry about the repo parts running out, we have you to make more!

[Brad Winder]

Wow! That's awesome!