UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Cabinet and Chassis Restoration and Refinishing

Notices

Cabinet and Chassis Restoration and Refinishing For help with cabinet or chassis restoration (non-electrical), please leave a message here.

Closed Thread
 
Thread Tools
Old 22nd Mar 2023, 10:40 am   #21
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Top Hat Fixing Washers Name

I have not used the gauge a lot but it seems good quality.

Googling Bolt Nut Screw Thread Checker Set Inch Metric Gauge Measuring Inspection Tool will find various online sales with some cost variations.

There are at least 2 size versions, I have the smaller version with 26 nut/bolt checkers.

My one only goes down to M4-07 & 6-32, so no good for smaller sizes.

David
DMcMahon is offline  
Old 22nd Mar 2023, 11:25 am   #22
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Top Hat Fixing Washers Name

Searching through my spare screws/fixings I found 2 examples of brass/brass coloured metal screw cups, they were slightly different size. The outside diameter of both were very borderline to properly cover the counterbored holes in the side panels and the centre hole diameter of one of one of them was too large with the head of M4 screw going straight through the hole.

So if I go with screw cups need to get suitably sized ones.

David
DMcMahon is offline  
Old 23rd Mar 2023, 10:49 am   #23
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Top Hat Fixing Washers Name

Went to B & Q to get some plumbing parts and had a look at their various screw fixings.

All their plastic combined screw cup and cover were all too small to adequately cover the counterbored holes in the side panels.

All their plastic screw cups and most of their metal cups also were too small but luckily found one steel cup that was a good size, it also retains an M4 screw. Also brought some SST M4 countersunk machine screws. Went for 30mm as thought they just would be long enough but they are too short. They did not have 35mm (the length of the original screws), they did have 40mm which I thought might be too long as I remember some of the fixing holes have metalwork some distance behind.

I think the SST countersunk screws will look OK in the steel cups, am not worried about the top of the screw heads showing.

David
DMcMahon is offline  
Old 23rd Mar 2023, 10:20 pm   #24
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Top Hat Fixing Washers Name

Quote:
Originally Posted by DMcMahon View Post

The original panels were rather slim white painted plywood, I have replaced these with wider solid hard wood panels which I think improves the overall appearance.


David
Added missing word in bold italic.

David
DMcMahon is offline  
Old 23rd Mar 2023, 11:02 pm   #25
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Top Hat Fixing Washers Name

Removed the wooden side panels to check for clearance if 40mm screws used.

The top 2 screw positions are fine but the bottom 2 screw positions are very borderline due to metalwork around 10mm behind the threaded screw holes but decided to try 40mm screws (so went and brought some).

Found that the M4 screws screwed in nicely (both original and new screws) when the side panels were not fitted, so indicating that the documentation was correct showing the screws to be M4.

Refitting the side panels once again made the screws tight to very tight to fully screw in.

Removing the screws and looking down the counterbored holes in the panels showed that the threaded holes in the chassis metalwork were not centralized in the holes, in fact in some cases they were well off centre.

This then triggered my memory. Around 3 years ago when I made the new hard wood panels, after measuring and marking up the hole positions, I found after drilling the holes that somehow I had screwed up and the drilled holes were not centralised around the threaded chassis holes. I tried to improve it by enlarging the holes but because when the screws are in the top hat shoulder trim washers there is little available movement/wiggle in the end of the holes it always ends up that the screws are tight when screwing in.

I fitted the 40mm machine screws together with the steel screw cups, all screws were able to be fully screwed in fairly easily and look definitely better than the original arrangement, particularly now that the domed head + integral washer of the original screws is not sitting on top & protruding out of the top of the top hat.

But a big issue is that when the screws are fully tightened some of the steel screw cups are pulled one way, so that part of the edge of the panel holes becomes uncovered (the cups only just cover the holes at best anyway) as can be seen in photos 2 and 3. Once again this is due to the misalignment of the chassis threaded holes to the panel holes.

To get the holes fully covered have fitted the 40mm countersunk screws with the original white top hat trim washers, some of them are very tight to tighten, somewhat improved this by adding grease on the end of the screws.

Even though the 40mm countersunk screw with white top hat is not bad would prefer the trim washer to also be steel so either need to find suitable steel top hat shoulder washers or find a steel cup washer that has a larger/wider outer diameter so that it fully covers the panel holes even when they they are pulled over during tightening plus with a centre hole that still retains the M4 screw head.

David
Attached Thumbnails
Click image for larger version

Name:	M4 screws easily screwing in.jpg
Views:	35
Size:	62.0 KB
ID:	275625   Click image for larger version

Name:	2.jpg
Views:	35
Size:	36.9 KB
ID:	275626   Click image for larger version

Name:	3.jpg
Views:	35
Size:	57.3 KB
ID:	275627   Click image for larger version

Name:	4.jpg
Views:	34
Size:	57.5 KB
ID:	275628  

Last edited by DMcMahon; 23rd Mar 2023 at 11:11 pm.
DMcMahon is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:00 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.