Replacing Potentiometer with thinner spindles: tip - UK Vintage Radio Repair and Restoration Discussion Forum

uk_snowman · 22nd Dec 2014, 8:39 pm

I dont know if this has been posted before, Sorry if it has.

Most rotary Potentiometer you buy now days like the ones in Maplin have thinner spindles than the vintage ones, Making it harder to fit control knobs back when one has replaced the Potentiometer.

The answer I have found that works, Since the spindle is made from plastic and once I have cut it to the correct length I then cut a cross at the end of the spindle using a junior hacksaw. Now the control know will fit nice and snugly.

Nickthedentist · 22nd Dec 2014, 9:37 pm

That's interesting, I would never have thought of doing that.

Have you ever tried joining the old spindle to the new pot's one?

Nick.

22nd Dec 2014, 10:00 pm

This is the 6mm vs. 1/4" (6.35mm) inch problem, unless you are really fussy it doesn't matter.

uk_snowman · 22nd Dec 2014, 10:09 pm

Quote:

Originally Posted by Nickthedentist

Have you ever tried joining the old spindle to the new pot's one?

No I have not, Have you? As I would think that would be quite awkward

McMurdo · 23rd Dec 2014, 1:22 am

I've joined spindles together, there's a particular (non-wireless) application that needs a very long spindle. I take a new pot and drill and tap a 2.5mm hole down the centre of its shaft (easy enough to do in a vice). I do the same with an extension piece (I've used shafts from old pots, bits of plastic and brass 6mm rod) and then join the 2 with a screw with the head cut off or bit of threaded bar. I loctite the thread, I suppose superglue would do.

The application is for a speed control on a type of lathe in a large machine shop and I havent had one back yet and they get a battering!

G6Tanuki · 23rd Dec 2014, 11:00 am

I've solved this by using some suitably-sized shim-brass (available from model-makers shops) to make up a very-thin-walled tubular sleeve to go round the spindle. It's sufficiently thin that the tip of the knob's grub-screw will form a dent in the brass and then engage with the control's spindle so providing a good grip.

It even works on spindles with a machined 'flat'.

vu2nan-nandu · 21st Jan 2015, 6:19 am

My parts supplier had plastic moulded hollow spindles to fit on to slender-moulded-spindle Philips potentiometers!

Regards,

Nandu.

22nd Dec 2014, 8:39 pm	#1
uk_snowman Hexode Join Date: Jun 2013 Location: Norwich, Norfolk, UK. Posts: 281	Replacing Potentiometer with thinner spindles: tip I dont know if this has been posted before, Sorry if it has. Most rotary Potentiometer you buy now days like the ones in Maplin have thinner spindles than the vintage ones, Making it harder to fit control knobs back when one has replaced the Potentiometer. The answer I have found that works, Since the spindle is made from plastic and once I have cut it to the correct length I then cut a cross at the end of the spindle using a junior hacksaw. Now the control know will fit nice and snugly.

22nd Dec 2014, 9:37 pm	#2
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,839	Re: Replacing Potentiometer with thinner spindles: tip That's interesting, I would never have thought of doing that. Have you ever tried joining the old spindle to the new pot's one? Nick.

22nd Dec 2014, 10:00 pm	#3
Guest Guest Posts: n/a	Re: Replacing Potentiometer with thinner spindles: tip This is the 6mm vs. 1/4" (6.35mm) inch problem, unless you are really fussy it doesn't matter.

23rd Dec 2014, 1:22 am	#5
McMurdo Dekatron Join Date: Jun 2009 Location: Staffordshire Moorlands, UK. Posts: 5,269	Re: Replacing Potentiometer with thinner spindles: tip I've joined spindles together, there's a particular (non-wireless) application that needs a very long spindle. I take a new pot and drill and tap a 2.5mm hole down the centre of its shaft (easy enough to do in a vice). I do the same with an extension piece (I've used shafts from old pots, bits of plastic and brass 6mm rod) and then join the 2 with a screw with the head cut off or bit of threaded bar. I loctite the thread, I suppose superglue would do. The application is for a speed control on a type of lathe in a large machine shop and I havent had one back yet and they get a battering! __________________ Kevin

23rd Dec 2014, 11:00 am	#6
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,995	Re: Replacing Potentiometer with thinner spindles: tip I've solved this by using some suitably-sized shim-brass (available from model-makers shops) to make up a very-thin-walled tubular sleeve to go round the spindle. It's sufficiently thin that the tip of the knob's grub-screw will form a dent in the brass and then engage with the control's spindle so providing a good grip. It even works on spindles with a machined 'flat'.

21st Jan 2015, 6:19 am	#7
vu2nan-nandu Pentode Join Date: Jul 2014 Location: Bangalore, India Posts: 132	Re: Replacing Potentiometer with thinner spindles: tip My parts supplier had plastic moulded hollow spindles to fit on to slender-moulded-spindle Philips potentiometers! Regards, Nandu. __________________ https://nandustips.blogspot.com