Fitting scale/pointer to a Jackson slow motion drive. - UK Vintage Radio Repair and Restoration Discussion Forum

G6Tanuki · 18th Dec 2022, 4:23 pm

I've got one of the Jackson 4511-type slow-motion drives I want to use to drive a VFO capacitor; problem is - it's the type without the flange-and-two-small-screw-holes in the bit that attaches to the capacitor.

Any suggestions as to how best to mount some sort of pointer or dial? My thoughts so far are along the lines of fitting a grommet to the centre of the dial (which will probably be cut from acrylic sheet, if only I can find a way to accurately cut large circles with smooth edges!) and then forcing it over the smooth cylindrical piece. Perhaps one of the relatively hard grommets used for mains-outlet backboxes?

Open to any suggestions/ideas - or should I just use a cheap-and-cheerful Chinese DFM kit to count the VFO?

Herald1360 · 19th Dec 2022, 1:23 am

Use a turns counting dial perhaps? That would give you, I guess, a 0-300 indication (180 deg capacitor, 6:1 reduction drive). Then stick a calibration graph à la HRO next to it!

Craig Sawyers · 19th Dec 2022, 9:28 am

You mean like this https://www.mainline-group.com/produ...91d5869a&_ss=r

Craig

Craig Sawyers · 19th Dec 2022, 9:29 am

Or this style from the same outfit https://www.mainline-group.com/colle...-part-no-4104a

CambridgeWorks · 19th Dec 2022, 10:37 am

I will see if I have anything suitable later today.
Rob

Bazz4CQJ · 19th Dec 2022, 11:50 am

Quote:

Originally Posted by Craig Sawyers

You mean like this https://www.mainline-group.com/produ...91d5869a&_ss=r

Craig

Wow; I've never heard of Mainline before and look at all the goodies they have!

B

G6Tanuki · 19th Dec 2022, 1:23 pm

I hadn't thoughtn of a turns-counting dial; I've got one here that's about 50mm diameter which might work if I can fathom out a way to mount it to the panel (it's designed to be retained by the pot mounting-bush which of course isn't there in this application).

My only worry about it would be that the Jackson drive is a friction type rather than positively geared between the slow and fast parts, so there is the risk of some slippage as a result of repeated usage.

I wish the likes of Eagle still sold the old style vernier drives from the 60s and 70s!

Asfar as an alternative 'dial' approach is concerned, I've discovered that a CD or DVD is a loose-ish fit over the slow-rotating part of the Jackson drive, and it's a good diameter so would give nice scale resolution.... time for some experiments!

mickm3for · 19th Dec 2022, 1:31 pm

Hi jab dog sell vernier drives https://www.ebay.co.uk/itm/363626389...Bk9SR5DW46WlYQ Mick

Herald1360 · 19th Dec 2022, 1:34 pm

One of those Mainline pointers could perhaps be glued to the 180⁰ collar of the drive or perhaps a piece of steel wire could be soldered to it and painted red?

G6Tanuki · 19th Dec 2022, 2:29 pm

Looking at the Jabdog vernier, that's pretty much the same as I remember them... but that one's rather small. I remember some being more like 55mm diameter, which would be better.

They do seem available online, but for $50 plus postage/tax....

The Mainline pointers assume the drive has a flange and screw-holes; I could always just buy a proper drive with flange and screw-holes.... Maybe it's an easier option than frobbing around with a home-lashed-together pointer/dial assembly for the existing Jackson drive?

CambridgeWorks · 19th Dec 2022, 6:43 pm

I last saw my pointer bits in a desk drawer, in the past year.
Unfortunately, I must have tidied up at some point and they are nowhere to be seen.
I need to go into my garage tomorrow for some other bits and will look there.
If I find anything in a day or so, I will post again.
Rob

Radio Wrangler · 20th Dec 2022, 3:20 am

Those are friction drives reliant on thick grease. A turns counter on the input shaft would eventually drift, driving you up the wall.

Turn up a flanged bush with a grub screw to fit the output shaft collar?

Or just buy a flanged one?

David

Craig Sawyers · 20th Dec 2022, 10:04 am

Quote:

Originally Posted by Herald1360

One of those Mainline pointers could perhaps be glued to the 180⁰ collar of the drive or perhaps a piece of steel wire could be soldered to it and painted red?

The Mainline drives have a flange with two screws fitted. Those screws fit the pointer. That flange is removable.

I've used their Jackson 4111 drives in projects before, and removed the flange (not needed) - it is just fitted with screws to the drive shaft. I'll have a rummage and find the ones I've taken off.

You'd be most welcome to one for the price of postage.

Craig

Craig Sawyers · 20th Dec 2022, 10:12 am

Actually looking at the flange, it is too deep to fit on the reduction shaft of your drive.

But I'll send it anyway - you might be able to surgically adapt it to fit your unit.

PM me your address

Craig

Bazz4CQJ · 20th Dec 2022, 1:52 pm

Maybe you should use a frequency meter module to get you started, get the rig working and then see what you feel you need in terms of the slow-motion drive and dial?

B

CambridgeWorks · 20th Dec 2022, 4:24 pm

Can't see it in my garage, so it is "lost" until I next see it again!
I did find almost a shoebox of other useful items that are now in my very full shack for safe keeping, plus some pots I wanted, so not any wasted time.
Sorry that I can't help out.
Rob

18th Dec 2022, 4:23 pm	#1
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Fitting scale/pointer to a Jackson slow motion drive. I've got one of the Jackson 4511-type slow-motion drives I want to use to drive a VFO capacitor; problem is - it's the type without the flange-and-two-small-screw-holes in the bit that attaches to the capacitor. Any suggestions as to how best to mount some sort of pointer or dial? My thoughts so far are along the lines of fitting a grommet to the centre of the dial (which will probably be cut from acrylic sheet, if only I can find a way to accurately cut large circles with smooth edges!) and then forcing it over the smooth cylindrical piece. Perhaps one of the relatively hard grommets used for mains-outlet backboxes? Open to any suggestions/ideas - or should I just use a cheap-and-cheerful Chinese DFM kit to count the VFO? Attached Thumbnails __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

19th Dec 2022, 1:23 am	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Fitting scale/pointer to a Jackson slow motion drive. Use a turns counting dial perhaps? That would give you, I guess, a 0-300 indication (180 deg capacitor, 6:1 reduction drive). Then stick a calibration graph à la HRO next to it! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Dec 2022, 9:28 am	#3
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,996	Re: Fitting scale/pointer to a Jackson slow motion drive. You mean like this https://www.mainline-group.com/produ...91d5869a&_ss=r Craig __________________ Doomed for a certain term to walk the night

19th Dec 2022, 9:29 am	#4
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,996	Re: Fitting scale/pointer to a Jackson slow motion drive. Or this style from the same outfit https://www.mainline-group.com/colle...-part-no-4104a __________________ Doomed for a certain term to walk the night

19th Dec 2022, 10:37 am	#5
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,859	Re: Fitting scale/pointer to a Jackson slow motion drive. I will see if I have anything suitable later today. Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd

19th Dec 2022, 1:23 pm	#7
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Fitting scale/pointer to a Jackson slow motion drive. I hadn't thoughtn of a turns-counting dial; I've got one here that's about 50mm diameter which might work if I can fathom out a way to mount it to the panel (it's designed to be retained by the pot mounting-bush which of course isn't there in this application). My only worry about it would be that the Jackson drive is a friction type rather than positively geared between the slow and fast parts, so there is the risk of some slippage as a result of repeated usage. I wish the likes of Eagle still sold the old style vernier drives from the 60s and 70s! Asfar as an alternative 'dial' approach is concerned, I've discovered that a CD or DVD is a loose-ish fit over the slow-rotating part of the Jackson drive, and it's a good diameter so would give nice scale resolution.... time for some experiments! __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

19th Dec 2022, 1:31 pm	#8
mickm3for Heptode Join Date: May 2015 Location: Chatham, Kent, UK. Posts: 965	Re: Fitting scale/pointer to a Jackson slow motion drive. Hi jab dog sell vernier drives https://www.ebay.co.uk/itm/363626389...Bk9SR5DW46WlYQ Mick

19th Dec 2022, 1:34 pm	#9
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Fitting scale/pointer to a Jackson slow motion drive. One of those Mainline pointers could perhaps be glued to the 180⁰ collar of the drive or perhaps a piece of steel wire could be soldered to it and painted red? __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Dec 2022, 2:29 pm	#10
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Fitting scale/pointer to a Jackson slow motion drive. Looking at the Jabdog vernier, that's pretty much the same as I remember them... but that one's rather small. I remember some being more like 55mm diameter, which would be better. They do seem available online, but for $50 plus postage/tax.... The Mainline pointers assume the drive has a flange and screw-holes; I could always just buy a proper drive with flange and screw-holes.... Maybe it's an easier option than frobbing around with a home-lashed-together pointer/dial assembly for the existing Jackson drive? __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

19th Dec 2022, 6:43 pm	#11
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,859	Re: Fitting scale/pointer to a Jackson slow motion drive. I last saw my pointer bits in a desk drawer, in the past year. Unfortunately, I must have tidied up at some point and they are nowhere to be seen. I need to go into my garage tomorrow for some other bits and will look there. If I find anything in a day or so, I will post again. Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd

20th Dec 2022, 3:20 am	#12
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Fitting scale/pointer to a Jackson slow motion drive. Those are friction drives reliant on thick grease. A turns counter on the input shaft would eventually drift, driving you up the wall. Turn up a flanged bush with a grub screw to fit the output shaft collar? Or just buy a flanged one? David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

20th Dec 2022, 10:12 am	#14
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,996	Re: Fitting scale/pointer to a Jackson slow motion drive. Actually looking at the flange, it is too deep to fit on the reduction shaft of your drive. But I'll send it anyway - you might be able to surgically adapt it to fit your unit. PM me your address Craig __________________ Doomed for a certain term to walk the night Last edited by Craig Sawyers; 20th Dec 2022 at 10:18 am.

20th Dec 2022, 1:52 pm	#15
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: Fitting scale/pointer to a Jackson slow motion drive. Maybe you should use a frequency meter module to get you started, get the rig working and then see what you feel you need in terms of the slow-motion drive and dial? B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.

20th Dec 2022, 4:24 pm	#16
CambridgeWorks Nonode Join Date: Jun 2010 Location: Spalding, Peterborough, Cambridgeshire, UK. Posts: 2,859	Re: Fitting scale/pointer to a Jackson slow motion drive. Can't see it in my garage, so it is "lost" until I next see it again! I did find almost a shoebox of other useful items that are now in my very full shack for safe keeping, plus some pots I wanted, so not any wasted time. Sorry that I can't help out. Rob __________________ Apprehension creeping like a tube train up your spine - Cymbaline. Film More soundtrack - Pink Floyd