Avoiding the "Bolt" sticking through the rack bott

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MartyMart

Well-known member
Joined
Feb 28, 2006
Messages
2,340
Location
Berlin for a while
How are you guys/gals doing this ? ... or are you not judging by some photos ??
Thinking of a small raised steel/alu panel to keep the bottom "clean" for
racking, mostly the Transformer but perhaps other smaller protrusions too.
Suggestions ?

Marty.
 
http://www.groupdiy.com/index.php?topic=4053&highlight=toroid+bolt
I was looking for a solution PRR posted but don't have time to mine for it. I've used this method to flushen up the head of toroid bolts. so I'll try to describe;
not too difficult with AL chassis. basically come up with a way to make a divot or recession where the screw head will be--if you can get curve/dished steel washers, like a pair of the one that comes with toroid tranies and a and then use a bolt to draw them together "spooning" with the chassis inbetween a nice dimple will result . this may be triky to find small enough hardware for though. another suggestion was to come up with some sort of bulbous die and a corresponding concave anvil to achieve a similar result
 
Thanks Shab, I do have a solution on one rack unit that I have "re-cycled"
but I guess it's a custom thing.
It's from a dual hard drive rack case - 2u and along the bottom front is a
raised piece of steel ( 1mm thick ) which bolts to the SIDE of the case, so
spans the whole left-right !
Very cool idea, it has various bolt holes in it and is about 1cm from the bottom of the rack.
Plenty of space to attach the drives, or toroids etc and has NOTHING sticking
out the bottom of the case.
I've seen other racks that have screw threads sticking out of the inside of the
case, but they seem "welded" in and are flush on the bottom.
I think this is a very cool idea, so may get some fabricated, though not all
rack cases have the same width ( other than the 19in rack ears )
!!
This particular Hard drive rack is for example, a good 6cm thinner than my
Tat 1176 case - side to side.
MM.
 
You could use "nutserts" they are like a rivet, with a thread through the middle, and sit flush on one side and stand up maybe 5mm or so on the other. You need to buy the nutserts and the nutserts gun, so not a real cheap solution, but really worth it if you are regularly building stuff. I use them as PCB standoffs as well. Should be able to buy them from your local nut and bolt shop.

Michael
 
[quote author="MartyMart"]How are you guys/gals doing this ? ... or are you not judging by some photos ??
Thinking of a small raised steel/alu panel to keep the bottom "clean" for
racking, mostly the Transformer but perhaps other smaller protrusions too.
Suggestions ?[/quote]

PEM fasteners.

-a
 
does anyone have any experience using these?

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Fasteners-Fixings/Fixings-PCB-Pillars/Self-adhesive-PCB-pillars/64771

Seem like a bit of a cheap option but could be useful in certain circumstances I reckon...
 
[quote author="rob_gould"]does anyone have any experience using these?

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Fasteners-Fixings/Fixings-PCB-Pillars/Self-adhesive-PCB-pillars/64771

Seem like a bit of a cheap option but could be useful in certain circumstances I reckon...[/quote]
Yes, I've used them quite often. The only drawback is that in a few years the adhesive eventually dries out and it comes unstuck.
They work best for horizontal, gravitational loads. Shear loading (stuck to the sides of the case) break away much sooner. Also make sure the surface is cleaned with alcohol before sticking.
 
[quote author="Walrus"][quote author="rob_gould"]does anyone have any experience using these?

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Fasteners-Fixings/Fixings-PCB-Pillars/Self-adhesive-PCB-pillars/64771

Seem like a bit of a cheap option but could be useful in certain circumstances I reckon...[/quote]
Yes, I've used them quite often. The only drawback is that in a few years the adhesive eventually dries out and it comes unstuck.
They work best for horizontal, gravitational loads. Shear loading (stuck to the sides of the case) break away much sooner. Also make sure the surface is cleaned with alcohol before sticking.[/quote]

Good advice - thanks Kevin :thumb:
 
I have tried to make a punch type tool (based on the Q Max punch principle) to make a recess in the base of rack cases for a toroidal transformer bolt - but haven't yet produced a satisfactory model.

The profile of the recess required is, of course, exactly the same as the shape of the dished washers supplied with your transformer - so this led me to the idea I currently use.

You need to punch or drill out a large enough diameter hole that the dished part of the washer will fit into, in the base of your rack cabinet.

You then fit this washer on the underside of the case - the bolt head is now well recessed, with only the thickness of the dished washer remaining proud of the base (1mm?).

Very effective and looks good.

I would never use self adhesive fixings inside anything that I design and make - as I have seen so many in commercial equipment fail as the adhesive dries out. Just not professional.....!


JG
 
I got a gizmo from Stew-Mac designed to extract stubborn knobs off Les Pauls....I'm pretty sure it will do a fine job making a small dimple to hide the screw head on the 1u cases where there's no room to spare.

http://www.stewmac.com/shop/Tools/Special_tools_for:_Electronics/Knob_and_Bushing_Puller.html

One could DIY the tool pretty easily!!!

Andy
 
There's a metalwork shop not far from me, I'm going to ask about getting
some "raised" bottom plates made, that will span the width of the case and
bolt to the sides, ( plenty of side bolt room on a rack case )
I will then be able to drill holes in this and fit hardware/PCB's to it, about 6mm
off the case "real" bottom.
The beauty of this also, is that the whole circuit can be lifted out of the rack
for work/fixes etc.
I think that's a very "pro" solution, though could make things tight in a 1U
case.
Alternative would be "Rivets" that have a screw attachment .... hmmm ...

MM.
 
[quote author="MartyMart"]There's a metalwork shop not far from me, I'm going to ask about getting
some "raised" bottom plates made, that will span the width of the case and
bolt to the sides, ( plenty of side bolt room on a rack case )
I will then be able to drill holes in this and fit hardware/PCB's to it, about 6mm
off the case "real" bottom.
The beauty of this also, is that the whole circuit can be lifted out of the rack
for work/fixes etc.
I think that's a very "pro" solution, though could make things tight in a 1U
case.
Alternative would be "Rivets" that have a screw attachment .... hmmm ...

MM.[/quote]

Hey Marty

Will you share the details of this when you've found out about getting this work done?

Sounds like it could be just the solution I'm looking for too.

Whereabouts in London are you by the way?

Cheers,

Rob
 
When I bought some cases from holt I got them to make up some dimpled plates, I asked for them to be made from scrap bit's of ally, they are 100mm square, they charged me £2 a plate as it was part of a order, I'm going to have to order from them again in the next month or so.

http://www.twin-x.com/groupdiy/albums/userpics/bolt_dimple.JPG

Mick
 
rob_gould said:
[quote author="MartyMart"]There's a metalwork shop not far from me, I'm going to ask about getting
some "raised" bottom plates made, that will span the width of the case and
bolt to the sides, ( plenty of side bolt room on a rack case )
I will then be able to drill holes in this and fit hardware/PCB's to it, about 6mm
off the case "real" bottom.
The beauty of this also, is that the whole circuit can be lifted out of the rack
for work/fixes etc.
I think that's a very "pro" solution, though could make things tight in a 1U
case.
Alternative would be "Rivets" that have a screw attachment .... hmmm ...

MM.

The boxes from modushop.biz have pierced baseplates available for mounting internals...very neat.

I just ordered a boat load of these boxes. For my next three/four projects I will redesign the PCBs to have mounting holes that fit the pierced base profile. Might be worth a look for an off the shelf solution. Prices are reasonable IMO.
 
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