Mechanical: M6 threaded hole, held in by a nut... - UK Vintage Radio Repair and Restoration Discussion Forum

ColinB · 1st Oct 2015, 8:37 pm

Hi,

I'm trying to create some M6 threaded holes (for machine screws), in a panel surface on a project I'm working on.

I'd like to obtain an item that I can bolt through the panel, and secure in place by an (obviously larger) nut, from the back. This item would have the M6 thread through it's middle, and be put through the panel like a normal bolt.

Is such a thing available, and does anyone know what name it's called(!)

Thanks,

Colin

Sean Williams · 1st Oct 2015, 8:49 pm

You can get things called "Rivnuts" - I use them quite a lot, you do need a proper tool to fit them, but once you have tried them you wont look back!

Another alternative is a "clinch" nut, these have to have a very accurately dimensioned hole drilled, and a threaded bush then fits from behind - the tightening action then pulls the bush into the panel and squashes into place - this solution is not quite as durable as the Rivnut.

HTH
Sean

Skywave · 2nd Oct 2015, 10:44 am

A hank-bush springs to mind: are these still available?

Al.

camallison · 2nd Oct 2015, 1:22 pm

Quote:

Originally Posted by Skywave

A hank-bush springs to mind: are these still available?

Yes, this is where I get mine from. The insert tool is also available, quite cheaply:

http://www.rivetwise.co.uk/rivets/sh...gon-pattern-46

Colin

PS - they're also available on eBay.

G6Tanuki · 2nd Oct 2015, 1:46 pm

As well as rivnuts etc, can you punch a square hole in the panel and then snap in a 'cage nut' from behind??

[They're the standard things used for fitting gear into racks in data-centres]

dseymo1 · 2nd Oct 2015, 5:15 pm

I suppose there's nothing to stop you drilling and tapping a larger bolt with a smaller internal thread.
Or for quick-and-dirty work, just epoxy a standard nut to the back of the panel!

julie_m · 2nd Oct 2015, 7:11 pm

This will depend what the panel is made of; but, could you weld a couple of bars of thicker metal behind it, that then could be drilled and tapped?

Otherwise, you would need crimp-fitted threaded bushes. These would normally be fitted using a press and jig in a factory, but you should be able to do it at home by hammering.

McMurdo · 2nd Oct 2015, 9:34 pm

rivnut/clinchnut/hank bush is the way to go I think, which one depends on you budget.

I've used rivnuts to replace torn-out welded nuts and the results are fantastic. Either system is a great addition to the toolbox and they can be bought in assorted kits with a range of tool mandrels.

AC/HL · 3rd Oct 2015, 12:48 am

I have an RS Clinchnut kit, and have used it as per your description, although they seem to have been discontinued now. You have to drill a hole in the panel, and the "nut" is crimped in the same way as a pop rivet. It further tightens in use.

Nymrod121 · 3rd Oct 2015, 12:46 pm

Quote:

Originally Posted by Skywave

A hank-bush springs to mind: are these still available?

Didn't Tina Turner issue a tutorial on the tolerances needed to fit these - ("hank-bush fitting limits") ?

Sean Williams · 3rd Oct 2015, 8:08 pm

Bill, The inserts are still available - we use them all the time at work!

julie_m · 3rd Oct 2015, 8:58 pm

Must fight urge to make any more Tina Turner song puns ..... We don't need another thread closed .....

Herald1360 · 4th Oct 2015, 1:06 am

Quote:

Originally Posted by julie_m

This will depend what the panel is made of; but, could you weld a couple of bars of thicker metal behind it, that then could be drilled and tapped

No need to weld- they could be held in place by light gauge countersunk screws if a flush front face is needed.

turretslug · 4th Oct 2015, 10:00 am

Would something along these lines fit the bill for the situation (usual disclaimer);

http://www.ebay.co.uk/itm/20X-M6-Spr...item2a33f60463

Two other types of fitting that I've frequently seen on de-mountable equipment but wish I knew the trade/colloquial terms for are short oval plates (think like a TO3 sort of profile) with thickened tapped centre and two smaller flanking holes for fastening by rivets or machine screws, and a pressed steel fitting that closely accomodates and holds in place a hex nut of the appropriate size and again fastens in place by smaller flanking holes.

Good luck in the quest.

FrankB · 20th Nov 2015, 4:38 am

They are commonly used here on aviation equip. and in commercial mfg. Almost any good "nut n bolt" supplier here has them in SAE and metric is also available, IIRC.. (Even Harbor Freight Tools has a kit of them. They are a Chinese tool dist. located in most major cities in the U.S. You can also order online. The installation tool looks like a pop rivet tool.)
I got my kit in the early 80's and it was made by Avibank.

Radio Wrangler · 20th Nov 2015, 8:03 am

Rivnuts..

As above, is like a pop rivet, but the mandrel screws into a thread in the rivet and the mandrel is re-usable. Apply like a pop rivet by squeezing with a similar tool, unscrew the mandrel and the thread it was in in the rivet is the size you wanted.

"PEMs" these are nuts with a sharp ridge on one side. The ridges can either be splined or hexagonal and have a circumferential groove. As said above, they need a very accurate hole size and a suitable material. They work in aluminium and mild steel. The ridge side is pressed into the hole. The ridge is a little too large, so it creates a curl of swarf which rolls round and into the circumferential groove. This leaves the nut sort of riveted onto the surface of the panel. They're strong if pulled from the opposite side of the panel, and weak if pulled from the same side. If one pulls out, the hole won't hold a replacement if you try to press another in.

"Nationals" Like a PEM but what you press in is a cage containing a floating nut which can't rotate. Works like a PEM but allows a little tolerance in alignment.

David

emeritus · 20th Nov 2015, 2:43 pm

I have a quantity of Pressnuts (as opposed to "Pressed nuts": some distributors get the names wrong ) and Rivnuts that I salvaged from the skip when the Marconi site I was based at closed, but not the tools to mount them. I have got round this by drilling a hole that gives as tight a fit as possible and then applying Araldite to the rear.

Julesomega · 20th Nov 2015, 3:37 pm

White Goods, especially cheapo products, tend to have fittings attached by self-tap screws. Feet on electric radiators are a particular problem.
Small (M3 - M4) steel nut rivets insert nicely in thin sheet steel improving greatly on the original construction
I bought a tool which inserts both rivnuts and pop rivets because it looks nice and is die-cast, but it is considerably less convenient to use that the cheap rivnut tools
A word of warning: I borrowed a tool but could not remove the damaged mandril, so I bought a new tool and then discovered that the mandrils are on a LH thread (of course)

1st Oct 2015, 8:37 pm	#1
ColinB Heptode Join Date: Apr 2003 Location: Newton Abbot, Devon, UK. Posts: 761	Mechanical: M6 threaded hole, held in by a nut... Hi, I'm trying to create some M6 threaded holes (for machine screws), in a panel surface on a project I'm working on. I'd like to obtain an item that I can bolt through the panel, and secure in place by an (obviously larger) nut, from the back. This item would have the M6 thread through it's middle, and be put through the panel like a normal bolt. Is such a thing available, and does anyone know what name it's called(!) Thanks, Colin

1st Oct 2015, 8:49 pm	#2
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Mechanical: M6 threaded hole, held in by a nut... You can get things called "Rivnuts" - I use them quite a lot, you do need a proper tool to fit them, but once you have tried them you wont look back! Another alternative is a "clinch" nut, these have to have a very accurately dimensioned hole drilled, and a threaded bush then fits from behind - the tightening action then pulls the bush into the panel and squashes into place - this solution is not quite as durable as the Rivnut. HTH Sean __________________ Engineers make things work and have spare bits when finished

2nd Oct 2015, 10:44 am	#3
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Mechanical: M6 threaded hole, held in by a nut... A hank-bush springs to mind: are these still available? Al.

2nd Oct 2015, 1:46 pm	#5
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Mechanical: M6 threaded hole, held in by a nut... As well as rivnuts etc, can you punch a square hole in the panel and then snap in a 'cage nut' from behind?? [They're the standard things used for fitting gear into racks in data-centres]

2nd Oct 2015, 5:15 pm	#6
dseymo1 Retired Dormant Member Join Date: Dec 2007 Location: Shropshire, UK. Posts: 3,051	Re: Mechanical: M6 threaded hole, held in by a nut... I suppose there's nothing to stop you drilling and tapping a larger bolt with a smaller internal thread. Or for quick-and-dirty work, just epoxy a standard nut to the back of the panel!

2nd Oct 2015, 7:11 pm	#7
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Mechanical: M6 threaded hole, held in by a nut... This will depend what the panel is made of; but, could you weld a couple of bars of thicker metal behind it, that then could be drilled and tapped? Otherwise, you would need crimp-fitted threaded bushes. These would normally be fitted using a press and jig in a factory, but you should be able to do it at home by hammering. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

2nd Oct 2015, 9:34 pm	#8
McMurdo Dekatron Join Date: Jun 2009 Location: Staffordshire Moorlands, UK. Posts: 5,271	Re: Mechanical: M6 threaded hole, held in by a nut... rivnut/clinchnut/hank bush is the way to go I think, which one depends on you budget. I've used rivnuts to replace torn-out welded nuts and the results are fantastic. Either system is a great addition to the toolbox and they can be bought in assorted kits with a range of tool mandrels. __________________ Kevin

3rd Oct 2015, 12:48 am	#9
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Mechanical: M6 threaded hole, held in by a nut... I have an RS Clinchnut kit, and have used it as per your description, although they seem to have been discontinued now. You have to drill a hole in the panel, and the "nut" is crimped in the same way as a pop rivet. It further tightens in use.

3rd Oct 2015, 8:08 pm	#11
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Mechanical: M6 threaded hole, held in by a nut... Bill, The inserts are still available - we use them all the time at work! __________________ Engineers make things work and have spare bits when finished

3rd Oct 2015, 8:58 pm	#12
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Mechanical: M6 threaded hole, held in by a nut... Must fight urge to make any more Tina Turner song puns ..... We don't need another thread closed ..... __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

4th Oct 2015, 10:00 am	#14
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,395	Re: Mechanical: M6 threaded hole, held in by a nut... Would something along these lines fit the bill for the situation (usual disclaimer); http://www.ebay.co.uk/itm/20X-M6-Spr...item2a33f60463 Two other types of fitting that I've frequently seen on de-mountable equipment but wish I knew the trade/colloquial terms for are short oval plates (think like a TO3 sort of profile) with thickened tapped centre and two smaller flanking holes for fastening by rivets or machine screws, and a pressed steel fitting that closely accomodates and holds in place a hex nut of the appropriate size and again fastens in place by smaller flanking holes. Good luck in the quest.

20th Nov 2015, 4:38 am	#15
FrankB Heptode Join Date: Oct 2005 Location: Olympia, Washington, USA. Posts: 664	Re: Mechanical: M6 threaded hole, held in by a nut... They are commonly used here on aviation equip. and in commercial mfg. Almost any good "nut n bolt" supplier here has them in SAE and metric is also available, IIRC.. (Even Harbor Freight Tools has a kit of them. They are a Chinese tool dist. located in most major cities in the U.S. You can also order online. The installation tool looks like a pop rivet tool.) I got my kit in the early 80's and it was made by Avibank. Last edited by FrankB; 20th Nov 2015 at 4:39 am. Reason: Additional supplier info.

20th Nov 2015, 8:03 am	#16
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,876	Re: Mechanical: M6 threaded hole, held in by a nut... Rivnuts.. As above, is like a pop rivet, but the mandrel screws into a thread in the rivet and the mandrel is re-usable. Apply like a pop rivet by squeezing with a similar tool, unscrew the mandrel and the thread it was in in the rivet is the size you wanted. "PEMs" these are nuts with a sharp ridge on one side. The ridges can either be splined or hexagonal and have a circumferential groove. As said above, they need a very accurate hole size and a suitable material. They work in aluminium and mild steel. The ridge side is pressed into the hole. The ridge is a little too large, so it creates a curl of swarf which rolls round and into the circumferential groove. This leaves the nut sort of riveted onto the surface of the panel. They're strong if pulled from the opposite side of the panel, and weak if pulled from the same side. If one pulls out, the hole won't hold a replacement if you try to press another in. "Nationals" Like a PEM but what you press in is a cage containing a floating nut which can't rotate. Works like a PEM but allows a little tolerance in alignment. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

20th Nov 2015, 2:43 pm	#17
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,339	Re: Mechanical: M6 threaded hole, held in by a nut... I have a quantity of Pressnuts (as opposed to "Pressed nuts": some distributors get the names wrong ) and Rivnuts that I salvaged from the skip when the Marconi site I was based at closed, but not the tools to mount them. I have got round this by drilling a hole that gives as tight a fit as possible and then applying Araldite to the rear.

20th Nov 2015, 3:37 pm	#18
Julesomega Nonode Join Date: Dec 2012 Location: Stockport, Greater Manchester, UK. Posts: 2,106	Re: Mechanical: M6 threaded hole, held in by a nut... White Goods, especially cheapo products, tend to have fittings attached by self-tap screws. Feet on electric radiators are a particular problem. Small (M3 - M4) steel nut rivets insert nicely in thin sheet steel improving greatly on the original construction I bought a tool which inserts both rivnuts and pop rivets because it looks nice and is die-cast, but it is considerably less convenient to use that the cheap rivnut tools A word of warning: I borrowed a tool but could not remove the damaged mandril, so I bought a new tool and then discovered that the mandrils are on a LH thread (of course)