MOTM

>In fact (Mark T., help me out!) a planer with a 10 degree offset could be
>used to angle the *inside* surfaces of the top and bottom wood pieces
>so that a 90 degree bracket 'tilts' perfectly!

You could indeed plane off the inside top to accomodate the required tilt angle, but I would prefer adding wood to the structure rather than taking it away. Although I don't see whay a metal shop would have a problem in bending the required angle for the rail.

It seem that most list members are looking to emulate the "Moog" type cabinet design and slope, which was also my original intent. I've since thought about other designs.

My suggestion for the rack rails would be to use wood, and as Larry mentioned , the brass threaded inserts. When you are constructing the cabinet and cutting the face angle of the top lid, your saw angle would already be set up, so you'd just have to rip a piece of wood to the appropriate length, about 1 1/2" wide and 1/2" tall ( this should easily clear the top edge of the MOTM PC bracket.) Another option would be to route a 1 1/2" channel along the inside of the top lid to a depth of 1/4" and cut your wood rails to 3/4" tall. You would then be able to "set " the wood rail into the cabinet top for an even more secure mounting method.
Somewhat overkill though.

_ Larry - do you have a source for these inserts that would fit to the MOTM threads? I haven't seen them locally or in the proper size in any of my catalogs. There are several types - press in, and thread in.

A question that I have for Paul and others, is would a rack rail made from wood cause any ground, etc..problems because the modules do not share a common conductive mounting point? I seem to recall an issue several years ago with some effects & amps in a rack where I worked even though the equipment was grounded. 


Mark T

>You could indeed plane off the inside top to accomodate the required tilt
angle, but I would prefer adding wood to >the structure rather than taking
it away. Although I don't see whay a metal shop would have a problem in
>bending the required angle for the rail.

Because the sheet metal "brake" used to bend 11ga steel (as opposed to say
0.0.62 al) can't be set
smaller than 30/45/60/90 "stops".

>My suggestion for the rack rails would be to use wood, and as Larry
mentioned , the brass threaded inserts. When >you are constructing the
cabinet and cutting the face angle of the top lid, your saw angle would
already be set up, >so you'd just have to rip a piece of wood to the
appropriate length, about 1 1/2" wide and 1/2" tall ( this should >easily
clear the top edge of the MOTM PC bracket.) Another option would be to route
a 1 1/2" channel along the >inside of the top lid to a depth of 1/4" and cut
your wood rails to 3/4" tall. You would then be able to "set " the wood
>rail into the cabinet top for an even more secure mounting method.

I think a 'channel' in the underside is the strongest way.

The main point I'm trying to make (remember, I'm looking at the *mass
manufacturing side*, not
the "Hell, let me at that band saw!" approach) is that the best you can hold
wood to is about 0.070", which
in sheet metal is a 4-lane hiway.

So, what the best solution is I'm guessing is you start at the bottom, the
when you are ready to drill into the
top, you just use the panel holes as a drill guide into that top wood rail.
Brass inserts are better that wood
screws, if we can get Larry to hunt them down.

As far as buying the 'normal' rails and turning them sideways, be aware of 2
things:

a) the tapped holes are #10, not #8 (as in the MOTM-19A). I *think* a #10
screw barely fits in the
existing panel holes, but certainly the "slop" is now all gone

b) the distance from the edge of the rail to the center of the holes need to
be so that the rail does not
hit the pots/mounting bracket/jacks. This dimension *will vary widely* from
supplier-to-supplier.

>A question that I have for Paul and others, is would a rack rail made from
wood cause any ground, etc..problems >because the modules do not share a
common conductive mounting point?

Sure they do! Each module has 2 18ga ground wires that are connected back at
the power
distribution board. This is called a "star ground", and is the absolute
lowest noise grounding scheme.

Paul S.

Wow, I don't read my mail for a short while and the MOTM conversations
explode!

So, I have a few things to correct here about "Moog Style" cabinets:

1. Yes, wood is used as the main brace on a "lower" Moog cabinet, it has an
angled front that matches the slope of the cabinet.

2. *MOOG MODULES ARE NOT MOUNTED TO WOOD!*

3. There is a standard metal rail that is mounted to the wood rails with
flat head wood screws.  The machine screws for the modules are short enough
that they don't go into the wood, or if they do, they don't go very far.

4.  The lower panel of half-height modules is broken up and attached with
hinges so you can get at the lower panels.  It is tough to do this from the
rear when the panels are at angle.

Having said all of this, why do you need to have a 90 degree bend in the
rails?  How 'bout flattening the current rails, lengthening them, and then
adding some holes for wood screws.  You could make them in buttable lengths
of 5U, 7U, and 10U or some set that allows folks to customize the lengths
they need.  This makes the bracing of rails a cabinet making problem and
probably makes for lower cost rails (no bend needed).  The wood rails should
be strong enough.  It worked for Dr. Bob and those cabinets are pretty
tough.

I was planning a 27U wide cabinet, 48.25" x 9.5" x 9.5" out of .75" wood
with the cheeks routed out to make them .5" at the front going back about
4.5".  This would match a Moog "upper" cabinet (I may be slightly off on the
height and depth in my measurements above).  If I couldn't make something
work with the chopped up MOTM rails, I was resigned to using wood screws but
I wasn't too happy about it.

	Eric

I would say for structural strength, as well as to give the greatest
flexibility in mounting options, no?

		-----Original Message-----
		From:	Crawley, Eric [mailto:esc@...]
		Sent:	Tuesday, February 01, 2000 1:18 PM
		To:	motm@onelist.com
		Subject:	RE: [motm] Cabinet Rails.

		... why do you need to have a 90 degree bend in the
		rails?

>Because the sheet metal "brake" used to bend 11ga steel
>(as opposed to say 0.0.62 al) can't be set smaller than
>30/45/60/90 "stops".

The podunk shop here in my small town of 10,000 has a fully adjustable
hydraulic brake.  They've done 10ga custom plates for me for mounting
EAW trapezoidal speakers.  It takes them a few tries to set up
the machine, but once it's set they can keep turning them out.

-Cary

> Because the sheet metal "brake" used to bend 11ga steel (as opposed to say
> 0.0.62 al) can't be set
> smaller than 30/45/60/90 "stops".

You may want to look into a different sheet metal shop. The key ingredient
here is
standardization, and how many people will be looking for a slanted style
cabinet,
and at what angle. And of course, how many !$!
Is this the same place that does the MOTM panels?

> >My suggestion for the rack rails would be to use wood, and as Larry
> mentioned , the brass threaded inserts. When >you are constructing the
> cabinet and cutting the face angle of the top lid, your saw angle would
> already be set up, >so you'd just have to rip a piece of wood to the
> appropriate length, about 1 1/2" wide and 1/2" tall ( this should >easily
> clear the top edge of the MOTM PC bracket.) Another option would be to
route
> a 1 1/2" channel along the >inside of the top lid to a depth of 1/4" and
cut
> your wood rails to 3/4" tall. You would then be able to "set " the wood
> >rail into the cabinet top for an even more secure mounting method.
>
> I think a 'channel' in the underside is the strongest way.

It would be one of the better methods for a wood rail.

> The main point I'm trying to make (remember, I'm looking at the *mass
> manufacturing side*, not
> the "Hell, let me at that band saw!" approach) is that the best you can
hold
> wood to is about 0.070", which
> in sheet metal is a 4-lane hiway.

I like the analogy!, And I do agree to a point. Most of the woodworking
equipment
that we have in our basements, garages, or in my case storage! may or may
not not be able to
hold the tolerance that you are looking for. There are too many variables
with wood,
material type, material age, temp., humidity, and skill. (I've cut wood to
exact dimension
only to find that is shrunk 1/4" more or less over time)
However, if you look at the mass manufacturing side, those shops will in all
probability
have CNC machines that can be set up to accomodate the required tolerances,
utilizing well
seasoned wood. You've done all the hard work already. It would be matching
wood to metal
rather than metal to metal.

Another option would be to investigate using plastics for dimensional
stability.
( I want to say one word to you - and one word only - Plastics!  (sorry,
couldnt resist))

> So, what the best solution is I'm guessing is you start at the bottom, the
> when you are ready to drill into the
> top, you just use the panel holes as a drill guide into that top wood
rail.
> Brass inserts are better that wood
> screws, if we can get Larry to hunt them down.

If we go back to the mass production concept , based on the input from all
of the list
members, if we could agree on a face angle of the cabinets, along with a 90
degree of
course, and lengths, You would set the standard for wooden rack rails.
Our cabinets could be designed around that standard.
( Did that sound like bringing the mountain to Mohammed?, or some iteration
thereof?)

> As far as buying the 'normal' rails and turning them sideways, be aware of
2
> things:
>
I call this the famous Mark T  $34.00 mistake! Someday, I'll build a 16
space rack unit for my other gear.

> >A question that I have for Paul and others, is would a rack rail made
from
> wood cause any ground, etc..problems >because the modules do not share a
> common conductive mounting point?
>
> Sure they do! Each module has 2 18ga ground wires that are connected back
at
> the power
> distribution board. This is called a "star ground", and is the absolute
> lowest noise grounding scheme.

Thanks, Paul I always learn something from you all the time!

I just love the MOTM stuff! Although I may not post that often, you can be
assured that I read all messages.
(I still have a my archive dating from 01/02/99.)

Looking at the big picture...
I dont think that there has ever been a synth company that was so receptive
to its users,
Or a synth company that had so many users, across so many locations,  with
such diverse backgrounds
that would allow them to be a part of the development to its success.

We are  GLOBAL!

It's the design concepts by Paul, and this "open mind" between all of us
that will make
the "MOTM " the Modular Synthesizer success story of Y2K.

I am happy to be a part of it all.

Mark T

mmt@...

I would argue that the 90 degree bend for long rails limits the number of
mounting options.  I certainly see the need for the rails for traditional
19" racks but for custom cabinetry, a wood support with a flat rail that can
be screwed on is very stable and requires much looser tolerances.  You could
mount some modules on the rails and place it into the cabinet and screw the
rails down without worrying about the wood imperfections.

I'll reiterate my proposal to Paul a bit differently:

- Continue to sell the current rails for rack mounting and structurally
"unsupported" applications
- Create buttable, flat, "rail stock" in a few fairly short lengths (10U or
smaller) that can be mounted in multiple sections on wood rails for cabinet
applications.  

I think this solves many of the problems Paul asked about:
1. You don't have to make one long length that is hard to build and ship.
2. You don't have to build special, carefully measured, wood pieces to hold
the L-shaped rails.
3. You don't have to worry about tight tolerances on the wood braces since
the rails don't have to be precisely aligned.
4. Removing the bend probably makes the rails less expensive to fabricate.

If folks are interested, I can take a few snapshots of the rails in my Moog
cabinets to give you a better idea.  Really, this is *much* simpler and
allows for more fabrication possibilities IMHO.

	Eric

> -----Original Message-----
> From: Tkacs, Ken [mailto:Ken.Tkacs@...]
> Sent: Tuesday, February 01, 2000 2:12 PM
> To: 'motm@onelist.com'
> Subject: RE: [motm] Cabinet Rails.
> 
> 
> From: "Tkacs, Ken" <Ken.Tkacs@...>
> 
> 
> I would say for structural strength, as well as to give the greatest
> flexibility in mounting options, no?
> 
> 
> 		-----Original Message-----
> 		From:	Crawley, Eric 
> [mailto:esc@...]
> 		Sent:	Tuesday, February 01, 2000 1:18 PM
> 		To:	motm@onelist.com
> 		Subject:	RE: [motm] Cabinet Rails.
> 
> 		... why do you need to have a 90 degree bend in the
> 		rails?
> 		
> 
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>

> From: Mark T <mmt@...>
_ Larry - do you have a source for these inserts that would fit to the MOTM
threads? I haven't seen them locally or in the proper size in any of my
catalogs. There are several types - press in, and thread in.

The ones I saw were common hardware items, not exactly the items you
describe.  They are held in the wood by a lip at the back with teeth.  I
forget what they are called.  I'll pick up a few for discussion and try to
get a photo.

Larry