Flightcase construction

[Oolong]

The distance between the two side panels is usually detailed as 486mm.

The maximum case size, (not including the rack ears) is 449mm max -

The opening between the inner edges of the rack strip is 450mm to allow the equipment to slide in.

The equipment is normally 483mm rack ear to rack ear (or front panel) - as in 19"

The distanc between fixing centres is 465mm

Since a picture says more than a thousand words and (at least for me) makes understanding this easier, here's a new illustration of mine which I've based upon your numbers above, Wikipedia and Plans.thefrankes.com's "All about racks & rails":

http://img221.imageshack.us/img221/6741/rackmeasuremr0.jpg

 

The numbers are slightly different from yours, but that's probably just because they've been rounded off metrically. Does it look correct?

 

What puzzles me now are the dimensions of the rack rails, because surely all the dimensions must differ if I use a different rack rail than the one in your example?

Wikipedia says that rack rails are 15.875mm (0.625") wide, while Plans.thefrankes.com is a little more loose about it, saying that they're usually between 15.9mm-19.1mm (0.625"-0.75") wide.

Looking at the drawings of the rack rails by Penn the dimensions differ yet again:

http://img404.imageshack.us/img404/7310/r0880dwgwl4.jpghttp://img125.imageshack.us/img125/9099/r0883dwgew6.jpg

http://img404.imageshack.us/img404/4598/r0860dwgbl0.jpg

 

I'll most likely be using the R0880 or R0883 (according to the Penn website the R0880 has been superseded by the R0883 although the supplier I'll most likely be using seems to sell the R0880 -still the same dimensions though except for the additional height-holes). I need to use this type of rack-rail as my rack will be pretty deep and allow for rack-shelves or something like that in order to support a deep, 19" racked computer. I'll be fastening the shelf or supporting rails between the two rack rails (front/rear rails).

I've also included the R0860 rail here, because I'll probably use that one for my second rack flightcase (which will be a "standard" 20U type without any special features such as the tiltable top-rack as I now plan to have).

 

...... Anyway, the R0880/R0883 seems to be 15.2mm wide, but I don't understand the distance from the side to the centre of the mounting holes. It says 12mm, doesn't it? But that only leaves 3.2mm for the square mounting hole (which must be bigger than the M6 (6mm) screw that mounts inside the nut for that square hole) in addition to a little space on the other side. Have they (Penn) filled in the wrong numbers in their drawings, or have I misunderstood it?

 

OK, so once I have the correct dimensions of the rack rails I assume the only width I have to change from my illustration above is the width between the left and right "wall" of the rack flightcase, right?

 

 

So for things like handles on the side with deep bowls, the total internal width available, wall to wall is 37mm wider than the maximum possible internal case size - allowing for a maximum of 18mm protrusion into the case, either side.

 

Again, I'm not entirely sure what you mean, but let me think aloud for a minute....

If we concentrate on the handles which will not interfere with the front-mounting of the 19" rack modules, but rather be placed further in (behind the rack rails that is);

The total internal rack-width (485.775mm) - the maximum width of a rack device (449mm) = 36.775mm

then add the plywood thickness (9mm) which should allow for a maximum internal protrusion of:

36.775mm + 9mm = 45.775mm for the handles.

 

Those numbers are far off from yours, so I must have misunderstood what you meant.

 

As for the latches that mount at the front of the rack, the story is a little bit different as I certainly won't have all that room for protruding internally.

The added internal width of the rack being 19.125" (485.775mm) as opposed to exactly 19" (482.6mm) should allow for some extra room for rack devices that don't comply 100% to the standard so they'll still fit.

In total, with that extra width I should now have 485.775mm - 482.6mm = 3.175mm extra (or 1.5875mm on each side).

I'm thinking that I should let the rack devices have this extra room instead of "stealing" it for the sake of deep extrusions of the latches.

Ideally, shouldn't the latches be protruding no more than a maximum of 9mm into the rack, from the outside (given that I'm using 9mm plywood)?

 

 

The bit you want is why this goes a bit wrong on the knob side of the rack strip. The butterfly catches are not fitted directly to the side panel, the are normally fitted over the top of the extrusion, so in the case of the one above, your extrusion size is 13mm, and the catch depth is 15.5, so you get a 2.5mm protrusion into the case - I'm pretty sure that when you normally use these HD versions, you also go for the thicker wall material extrusion. The slimmer, lighter weight catches are a better match, as the medium penn latches are 13mm deep to match the extrusion.

 

Do you have an illustration to show what you mean?

I'll try to draw one illustrating what I think you mean, later on. But for now, although I don't know what you mean by the "knob side of the rack strip" I do get that you're saying that the latches don't mate directly with the outer part of the rack (the wood that is), but rather on the outside of the extrusions, lifting the latch a little bit outwards, making the protrusion into the rack less. Is this what you mean?

Still, I assume that won't account for more than a mm or so....

 

I must still be misunderstanding something :D

 

For the equipment to slot into the 19" rack, only the front face is 19" wide. Behind the face it has to be slimmer than 19" for it to slot into a rack. This gap gives you the space for your latches.

 

But the latches go in the front (and rear) of the rack!

So the front latches will block any insertion or removal of 19" rack devices if they're too deep.

 

 

Can someone recommend easy to use CAD software for the Mac, which is either free or doesn't cost a fortune?

 

Sorry to sound like a stuck record but Google Sketchup, there is a Mac version.

 

Roderick`s beautifully drawn butterfly catch DXF imports without difficulty, just needs to be rescaled. For extrusion import the .jpgs you have and trace round them, you can then literally extrude your extrusions for use in the program.

 

Just hoping somone will help expand the library ;-)

 

I've tried Google's Sketchup, but it looks more like a 3D package for buildings etc. than something I can use to draw a flightcase or similar items with.

 

I also couldn't load the DXF file into it -how did you do it?

Perhaps the Mac and PC versions differ a little bit.

[paulears]

Blimey!

 

The only critical dimension is the distance between centres in your finished rack. The Penn rack strip is wider than some, this just means the aide panels are slightly further apart. Just adjust your side panel distances to match the rack strip you choose to use.

 

Oh - mm to 3 decimal places? .5 of a mm as the smallest dimension seems sensible, given the tolerances of manual construction.

[Dave]

Three quick things from me:

 

(a) As someone has mentioned before, note particularly that rack strips differ and the oft-quoted figure of 486mm between side walls does not always apply.

 

(b) Flight case construction is precision engineering - you do need to cut materials to 0.5mm accuracy and do very good mitres. You also need to be able to cut the panels to this accuracy and make sure the corners are exactly 90 degrees.

 

© I once visited a flightcase manutfacturer and they said that the best way of making a case is always to assemble a box from pinned wood (possibly glued as well) and then rivet on angle extrusion. They said using casemaker was not as strong.

 

In my opinion, having made a couple of flightcases, it's best left to the pros. They have factories, specialised machinery, and the experience of making thousands of cases. Home-made ones will never be as good.

 

HTH

 

Dave

[musht]

I've tried Google's Sketchup, but it looks more like a 3D package for buildings etc. than something I can use to draw a flightcase or similar items with.

 

I also couldn't load the DXF file into it -how did you do it?

Perhaps the Mac and PC versions differ a little bit.

 

Be suprised, its great for working out how something will fit together in 3d be it a building , game scene, case or electronics package. Its vector based though so dosen`t treat objects as solids, be careful about putting things `through` each other.

 

It does stay more accurate at larger scales, so drawing at 10 times scale and then scaling down can help with sub mm accuracy.

 

File > Import will give you choice of importing things like DXF/DWG, 3DS and even JPG or TIF. Only the paid for version will export in these formats.

 

This is what happens when you import a jpg, trace then extrude it:

 

http://img412.imageshack.us/img412/5628/fcetm8.th.jpg

 

Couple of components that might help:

 

http://sketchup.google.com/3dwarehouse/det...amp;prevstart=0

 

http://sketchup.google.com/3dwarehouse/det...amp;prevstart=0

 

 

One last tip , if you do build it yourself, use a router not a saw to cut panel.

[cedd]

Reverting slightly back to the topic title of fligtcase construction, rather than rack case construction;

 

I decided to case my zoom H4. Being such a small piece of kit, it didn't want a bulky wooden case, but a camera - type bag just didn't offer the protection.

 

We've just had our house re-clad and new double glazing fitted, and the guys kindly left me some spare bits of 8mm plastic board the use for facia's. And wow what good stuff it is! Now I know it's expensive, but it's very lightweight and so easy to work with.

 

Assembled a box in 15 mins (with the hel of bandsaw and bandfacer) with 45 degree angled corners, screwed together with self-tappers and then stuck and sealed using an adhesive sold by screw fix called (I promise!) "sticks like s*it". And boy does it!

Come out with a very nice lightweight case with a really nice finish (on a flightcase!!!!).

 

Very good for casing small kit if you can arrange for some of the stuff to fall off the back of a lorry!

 

 

C

[lightsource]

Sorry, but this topic is going Outa' Space.

 

With reference to various previous comments, regarding CAD software etc, etc. What would you do without a PC and the Internet?. You do actually realise that flightcases were being built decades before Computers and CNC machines

 

 

Why would you ever want to waste time using CAD software when you can roughly draw the case with pen and paper, in a couple of minutes, then build it from there. It's the dimensions that are important ( remember to factor in wood thickness when you work out the dimensions for the cut). NOT the pretty CAD picture you print out.

 

Power Tools need practice, to use accuratley, so spend your time doing this, rather than wasting your time learning how to 'draw' the finished product.

 

It also doesn't have to be sub-millimetre accurate. Fairly accurate will do, and will save you a fair amount of money, compared do most commercially available cases.

[Oolong]

Why would you ever want to waste time using CAD software when you can roughly draw the case with pen and paper, in a couple of minutes, then build it from there.

 

I asked about the CAD software because of the illustrations I've made here.

For me at least, a picture explains these things way better and clearer than lots of words, but using Photoshop elements takes me forever to do.

 

As for the actual construction of the flightcase, sure -pen and paper will do nicely. I already have lots of ideas jotted down on a bunch of paper.

 

 

Blimey!

 

The only critical dimension is the distance between centres in your finished rack. The Penn rack strip is wider than some, this just means the aide panels are slightly further apart. Just adjust your side panel distances to match the rack strip you choose to use.

 

By the "aide panels" you mean the sides of the rack, don't you?

As for the Penn racks strips, I really need to know the actual dimensions before I start making my construction drawings. Has anyone here used (or have access to) the Penn R0880 or R0883 rack strips?

The dimensions in the drawings (which I've taken from the Penn website and included in one of my earlier postings here) just don't make sense.

 

 

Oh - mm to 3 decimal places? .5 of a mm as the smallest dimension seems sensible, given the tolerances of manual construction.

 

I agree. I just thought it would be a good idea to be that accurate at this stage, then round off things later on.

0.5mm tolerance will probably be hard enough to do without special tools.

A relative of mine has a small workshop which includes an electric saw which (as far as I remember) looks rougly like this:

http://img408.imageshack.us/img408/1238/sawdn4.jpg

 

I'll give him a call and talk about it, but how do the pros cut plywood like this?

 

 

Getting back to the butterfly latches...

I was told by someone that 9mm plywood (the "flightcase" type which has a protective plastic film on top) is more like 9.5mm, which of course is good for this

I'll check with my wood supplier before I get started.

 

I'm still not sure I understand how to avoid any problems of the butterfly latches not protruding too much inwards (thereby blocking the 19" rack modules when inserting or removing them).

Perhaps someone with a finished rack flightcase could take some photos and post them here?

I've found many photos on the web, but none of them are detailed unfortunately.

[paulears]

You are making this a million times more complicated than it is. (and yes, sorry about the typo, it was Side).

 

The Penn diagrams are really detailed - everything is on there. I do have some offcuts of the big side strip - but measuring it produces meaningless results as the Penn measurements are spot on, mine are just close.

 

If you are really unsure about the dimensions, then why not just order the parts, based on what you already have, then you will see how they go together. If you bolt a piece of your rack kit to the strips, you'll find that the width is slightly adjustable, due to the rack captive nuts being able to move left/right slightly - so even if you get the side to side internal measurement wrong by a couple of mm, it still works!

 

 

If you really want photos, why not visit your local venue during a get in, and ask if you can take a photo or two of their racks - they will think you are a bit mad, but I can't see them saying no.

 

The film on the panels is not important - less than .5mm is not worth worrying about. The only critical thing is making sure the panels fit into the extrusion!

 

Some of the fittings get professionally bodged anyway. I'll knock up a quick drawing to explain what I mean.

 

http://www.eastanglianradio.com/rack2.jpg

 

The drawing is to scale, and shows the larger section of the normal butterfly catch sitting into the side panel. Note that the mating surfaces of the extrusion have the mating edge of the catch sitting on top where it is riveted. The other end of the catch is therefore about 1.5mm above the side panel, due to the thickness of the extrusion. All that happens is the catch gets forced down, and then riveted - meaning it gets forced into position. There will be slight gaps, but the material bends a little and the fitting is secure. So hopefully you can see that there is simply no need to worry about the depth of the film covering - in this instance, the accuracy isn't important. However, other dimensions do need accuracy, particularly when it comes to angles and parallel panels.

 

http://www.eastanglianradio.com/rack3.jpg

 

Some rack manufacturers don't do it this way, and file away the extrusion where the edge of the catch fits - making the plate sit at panel height - just takes longer, and no doubt increase price. If you are doing it yourself, why not do this?

 

One thing - what are you planning to put in the actual rack? Amps? If the rack is only intended to hold lighter weight kit, then the expense of these particular rack strips may not be worth it - maybe just a simple right angle strip would do?

 

 

Buy the correct hardware. Make sure you get rivets that are long enough, have the correct sized hole and washers. Also check that you get the correct rack nuts for the penn type HD strip - it is pretty thick and needs the nut cages to be slightly deeper.

[Pete McCrea]

This is how 5 Star do it.....

[robloxley]

I once visited a flightcase manutfacturer and they said that the best way of making a case is always to assemble a box from pinned wood (possibly glued as well) and then rivet on angle extrusion. They said using casemaker was not as strong.

I'd say this is true, PVA glued plywood joins are incredibly strong, especially with some external aluminium protection from knocks. A biscuit jointer can make producing the boxes accurate and quick

[musht]

A relative of mine has a small workshop which includes an electric saw

Thats a scrollsaw for cutting fine shapes out of wood, not good for long accurate cuts.

CNC router is what big shops will use, at home combo of circular saw for big cuts and router for holes and neat edges. Router dosen`t smash the edge of the ply as you cut.

 

Sure Oakleigh use biscuit joints and glue angle around corners so the box is rigid before the extrusion is applied. if one panel gets cuffed though hard to repair the box.

[paulears]

Biscuit joints and thicker panels, are strong - add aluminium for protection and a little more strength and you have a great case, but a very heavy one. A 12U diamond board case weighs less than my 4U solid one!

[Oolong]

The Penn diagrams are really detailed - everything is on there. I do have some offcuts of the big side strip - but measuring it produces meaningless results as the Penn measurements are spot on, mine are just close.

Are you talking about the Penn R0880 and R0883 "double" rack strips?

If you have these strips and could give me the dimensions, if even just roughly, it would be of great help to me.

I've had another look at the Penn R0880/R0883 rack strip drawings (from the Penn website) but it still doesn't make sense to me. Let me try to explain this a little better with another illustration:

http://img219.imageshack.us/img219/1083/r0880dimensionshx0.gif

 

I'm concentrating on the front of the rack strip (the side where the 19" synth/effect modules mount) and not the sideways "support" sides.

Now, the drawing says that the full width is 15.2mm, and 12mm from the rightmost side of the strip to the centre of the square holes.

That should leave only 3.2mm from the centre to the left hand side of the strip.

 

But that doesn't make sense, because the screws are 6mm in diameter (M6) meaning 3mm to each side, resulting in only 0.2 left over, which absolutely doesn't make sense!

And the square holes must surely be bigger than 6mm as those nuts (and fasteners) are supposed to go there.

 

 

If you are really unsure about the dimensions, then why not just order the parts, based on what you already have, then you will see how they go together.

 

Yes, that's absolutely an option, but I was hoping to straighten out all the details first so I can possibly fill in a complete order and get some discount.

 

 

If you really want photos, why not visit your local venue during a get in, and ask if you can take a photo or two of their racks - they will think you are a bit mad, but I can't see them saying no.

 

Hehe

Actually, chance had it that I ended up in an event this weekend and luckily had brought my camera along. That gave me the chance to check out lots of details that had confused me, which I've asked about here.

I believe I did get a better understanding of certain things, but the comments here seem to be inconsistent of my findings which puzzles me. Perhaps there are just different ways of doing things, or there were details I couldn't see.

I'll get back to that later.

 

Anyway, getting back to the rack strip. I didn't find any racks exposed strips (i.e. no 19" modules mounted), so I couldn't check out the rack strip dimensions, but I did notice that the racks had their strips mounted on blocks of wood as opposed to directly on the sides of the rack, thereby leaving room for the inwards protruding latches as I've previously suggested.

Here's a photo:

http://img211.imageshack.us/img211/2351/rackrailsprotrusiontn7.jpg

 

I can clearly see how blocking the insertion/removal of the 19" modules is avoided because of the rather deeply protruding butterfly latch (i.e. the latch protrudes beyond the sides of the rack).

But from previous replies I gather this isn't the only way to do it?

 

 

The film on the panels is not important - less than .5mm is not worth worrying about. The only critical thing is making sure the panels fit into the extrusion!

 

That shouldn't be any problem as long as I buy extrusions with widths suited for the plywood I'll be using.

I guess 10mm extrusions should be OK for 9mm plywood. They're slightly bendable as well, aren't they, so when I mount them firmly with rivets their opening ends should bend downwards and "touch" the wood, shouldn't they?

Leaving them open could cause problems if it's raining and water runs inwards, within the gap.

 

As for your reply comments on the butterfly latch; I'll look into what you're saying once again, because I just don't understand how I can use something that extrudes inwards in the rack without blocking access to the 19" rack modules to be mounted there.

Although I haven't built a rack flightcase before, common sense tells me that I either have to protrude the rack strip inwards (as shown in the photo above) and thereby also extend the total width of the rack, or use shallow latches which don't protrude beyond the width of the wood thickness (or rather the width of the edge-extrusions).

 

One thing - what are you planning to put in the actual rack? Amps? If the rack is only intended to hold lighter weight kit, then the expense of these particular rack strips may not be worth it - maybe just a simple right angle strip would do?

 

No amps. Just musical equipment (synths, samplers etc.), effects, and a computer.

It's the computer that has caused me to think about using "double" rack strips. I know that the cost will be considerably more as I believe they cost about twice that of the simple rails, and I need 4 of them instead of just 2 in the front, but considering that the computer will be quite deep I think that's the way to go.

 

Oh, and then there's the tiltable rack-mixer on the top. I'll have to use a Penn R2860-SET for that, in addition to a couple of normal rack strips.

 

Talking about prices, are there any online price-lists available for Penn's hardware?

My dealer doesn't have a complete price-list, but gives a quote on demand. I'd rather know approximate prices as I plan this before I send in for a quote.

 

 

Buy the correct hardware. Make sure you get rivets that are long enough, have the correct sized hole and washers. Also check that you get the correct rack nuts for the penn type HD strip - it is pretty thick and needs the nut cages to be slightly deeper.

 

That should be the Penn S1170. The link says they should fit the R0880/R0883 "double" rack strips.

 

Looks like I've figured out most of the details with the help of you and others replying as well as first hand inspection of ready-built racks.

But the latches and rack strips still puzzle me.

Penn has a huge range of butterfly latches. Building a 20U rack makes me think that I probably need "large" or "medium" sized latches. At least that's what the professionaly made racks seem to be using.

Why are there so many types of latches that seemingly are more or less the same?

I also noticed that almost all of them are about 13mm deep while I should look for something around 9 or 10mm deep if I'm not to add an inwards-protrusion bit of plywood for the rack strips that is.

 

How did you solve this problem in your rack? How thick wood did you use, and how deeply did the latches protrude?

[Roderick]

I can't believe I am writing this, but here it goes.

These are the dimensions you posted earlier:

http://img125.imageshack.us/img125/9099/r0883dwgew6.jpg

The 15.2mm you refer to is the depth of the strip, not the width.

The whole strip is 71mm wide, from the edge to the centre of the hole is 64mm, ergo 71mm - 64mm = 7mm - what is the problem?

 

With all respect, if you have problems with reading very clear information from suppliers, maybe you should reconsider this project.

[Oolong]

Yes, I admit that I certainly have a lot to learn, but with all due respect I think you're wrong, or have misunderstood what I've meant.

 

I've compared the drawing with the photo of the rack strip and I can't see it any other way than 15.2mm being the width of the strip. The width being the front part where the 19" rack modules are mounted:

http://img152.imageshack.us/img152/6461/r0883detailmj5.jpg

 

The 71mm width that you describe is the side that mounts on the side of the rack flightcase, which is the reason for the round holes.

 

To further illustrate this, here's the R0855 rack shelf support which mounts in between two rack strips. The 305mm length being the depth of the rack flightcase:

http://img529.imageshack.us/img529/5816/r0855dwgih1.jpg