Tektronix 564 Allen Key Knob Size? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

factory · 14th Dec 2018, 8:32 pm

I can't remember if I've posted this before on here, but I scanned the tables for UNC/UNF thread & drill sizes and created a small wall chart for my shed (as I work on a lot of vintage US made test gear & O&R engines).

David

WME_bill · 15th Dec 2018, 3:49 pm

Tek knob screws. Identifying thread sizes.
Thanks to "factory" for his useful table.

The attached summary and comparison of the usual threads may also prove useful. Use a micrometer to measure bolt diameters and compoare with a few known nuts and bolts.
The Tek knobs seem to be UN6-6 (like a coarse 4BA. Get the thread pitch by comparison with 2BA/ 3/16 BSF).
I tend to pick up and identify any odd small nuts and bolts to act as a standard in future.

Allen Keys.
The sizes I use most are:
0.05 inch/ 1.27mm, for small knobs on HP, Cossor, Solartron, Farnell.
0.625 inch/ 1.59mm/ 1/16th for larger knobs on Tek, HP, Marconi, Telequipment, Solartron.
Philips seems to use collett fixing, which needs tubular spanner or a fine pointed pliers.
wme_bill

M3VUV51 · 15th Dec 2018, 5:24 pm

I had to take the front off of my old tek 453 to change the power and a sweep trig D indicator lamps(fitted led's),the worst part of the job by far was finding an allen key to fit the small red knobs,also had to change the shaft and flexible coupler for ch 1 vots/div knob,for the coupler i used the centre from a chock box and the shaft a bicycle spoke.never did find what size it was!

factory · 16th Dec 2018, 2:58 am

Quote:

Originally Posted by WME_bill

The Tek knobs seem to be UN6-6 (like a coarse 4BA. Get the thread pitch by comparison with 2BA/ 3/16 BSF)

Did you mean UNC-6 (instead of UN6-6), I did verify the size of the Tek control knob grub screws using a known size #6 UNC (O&R engine cover) screw before my first post on Friday.

Thanks for the comparison table, looks very useful too.

David

M3VUV51 · 17th Dec 2018, 4:54 pm

just out of interest do the Americans use bsf or ba threads?,from what i remember the grub screws in my 45 looked way finer pitch than unc!,regards m3vuv.

TonyDuell · 17th Dec 2018, 6:01 pm

There is a finer-than UNC (UniFied Coarse) thread. It's UNF (UniFied Fine). For example #6 (diameter) which is what we have been discussing here is 32 tpi (threads per inch) pitch in UNC and 40 tpi in UNF.

Finding BA or BSW/BSF threads in American equipment is very uncommon, it probably only happens when a British-built subassembly is used. Just as it is rare to find UNC or UNF threads in British equipment.

MotorBikeLes · 17th Dec 2018, 9:15 pm

Tony, whilst I have not seen it with 'scopes and other test gear, with M/cycles, BSF and BSW (+ CEI and BA) were common place, around the '60s, many moved to the use of UNF and UNC. After just a few years, it was metric on almost everything. In the US they had the sense to stick with what they knew, other than changing names NF and NC to UNF and UNC. U=Unified.
I think something similar happened with Brit cars, but not sure.
Les.

TonyDuell · 18th Dec 2018, 6:04 am

I should have been more specific, I was talking about the screw threads used on items that are on-topic here.

Yes, British vehicles (sorry mods) used UNC/UNF nuts/bolts, but not in the small sizes like the 4-40, 6-32, etc. You'd find larger ones in the engines. But the electrical parts would be almost all BA.

In general UK electronic equipment of the time would use BA fixings too.

American electronic equipment (test gear, computers, etc) used the small-size UNC and UNF fixings. If (like me) you work on PDP11s, HP9800s, etc computers and Tektronix 500 series 'scopes you will come across them. A good stock of spares and a set of taps and dies of that thread series is almost essential.

Myford lathes used some BSW up to the very end of the Nottingham-built ones (and may still do). I am told they found they could save considerable money by using metric fixings inside the machines (e.g. to fix the headstock to the bed) as the BSW bolts were expensive, but they kept said thread for compatibility on the accessory fixings.

Now just about all electronic stuff uses the metric fixings, of course.

15th Dec 2018, 5:24 pm	#23
M3VUV51 Banned Join Date: Feb 2018 Location: Horncastle, Lincolnshire, UK. Posts: 203	Re: Tektronix 564 Allen Key Knob Size? I had to take the front off of my old tek 453 to change the power and a sweep trig D indicator lamps(fitted led's),the worst part of the job by far was finding an allen key to fit the small red knobs,also had to change the shaft and flexible coupler for ch 1 vots/div knob,for the coupler i used the centre from a chock box and the shaft a bicycle spoke.never did find what size it was!

17th Dec 2018, 4:54 pm	#25
M3VUV51 Banned Join Date: Feb 2018 Location: Horncastle, Lincolnshire, UK. Posts: 203	Re: Tektronix 564 Allen Key Knob Size? just out of interest do the Americans use bsf or ba threads?,from what i remember the grub screws in my 45 looked way finer pitch than unc!,regards m3vuv.

17th Dec 2018, 6:01 pm	#26
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Tektronix 564 Allen Key Knob Size? There is a finer-than UNC (UniFied Coarse) thread. It's UNF (UniFied Fine). For example #6 (diameter) which is what we have been discussing here is 32 tpi (threads per inch) pitch in UNC and 40 tpi in UNF. Finding BA or BSW/BSF threads in American equipment is very uncommon, it probably only happens when a British-built subassembly is used. Just as it is rare to find UNC or UNF threads in British equipment.

17th Dec 2018, 9:15 pm	#27
MotorBikeLes Nonode Join Date: Dec 2012 Location: Kirk Michael, Isle of Man Posts: 2,350	Re: Tektronix 564 Allen Key Knob Size? Tony, whilst I have not seen it with 'scopes and other test gear, with M/cycles, BSF and BSW (+ CEI and BA) were common place, around the '60s, many moved to the use of UNF and UNC. After just a few years, it was metric on almost everything. In the US they had the sense to stick with what they knew, other than changing names NF and NC to UNF and UNC. U=Unified. I think something similar happened with Brit cars, but not sure. Les.

18th Dec 2018, 6:04 am	#28
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Tektronix 564 Allen Key Knob Size? I should have been more specific, I was talking about the screw threads used on items that are on-topic here. Yes, British vehicles (sorry mods) used UNC/UNF nuts/bolts, but not in the small sizes like the 4-40, 6-32, etc. You'd find larger ones in the engines. But the electrical parts would be almost all BA. In general UK electronic equipment of the time would use BA fixings too. American electronic equipment (test gear, computers, etc) used the small-size UNC and UNF fixings. If (like me) you work on PDP11s, HP9800s, etc computers and Tektronix 500 series 'scopes you will come across them. A good stock of spares and a set of taps and dies of that thread series is almost essential. Myford lathes used some BSW up to the very end of the Nottingham-built ones (and may still do). I am told they found they could save considerable money by using metric fixings inside the machines (e.g. to fix the headstock to the bed) as the BSW bolts were expensive, but they kept said thread for compatibility on the accessory fixings. Now just about all electronic stuff uses the metric fixings, of course.