Chassis thickness

[basschops1528]

I recently had a chassis made at a local bike and it came out terrible. They used what looks like 1/8" think aluminum because I said it needed to hold a decent amount of weight. The front and back panels aren't level or square, the sides aren't flat, it looks like a mild trapezoid, and the dimensions aren't even close. What's a good thickness for a revibe project or any other small project so that I can get them to do a better job? Maybe someone could list different thicknesses for common amps in increasing size?

[Paul1453]

The more experienced guys have given me some recommendations on a recent thread of mine.

Do a quick search, you'll find it.

Basically for aluminum they said I need like 14-16 gauge, or almost twice as thick as what you got.

If you are getting serious about making multiple guitar amps, you might consider getting a metal brake like I did.

I still haven't found a good source for nice thick aluminum sheets at a good price yet.

I did get some decent smaller pieces of aluminum at the scrap metal yard for cheap.

They won't make a full size chassis, but will likely be OK for something smaller like the Hoffman Stout. 

[sluckey]

I like .090" aluminum.

[basschops1528]

Thanks Paul for the info. The box I have is 1/8" Like I said which equates to 0.125 which is pretty darn thick. Would half that size be sufficient to hold the revibe trannys? Its about 0.0625 14-15 gauge aluminum

[HotBluePlates]

... they said I need like 14-16 gauge, or almost twice as thick as what you got. ...

I recently had a chassis made at a local bike and it came out terrible. They used what looks like 1/8" think aluminum ...

The last chassis I had made to support transformers (a 60w OT and matching PT) was 12ga (0.0808"), Hoffman's aluminum chassis is 11ga (0.0907"). If you really got a 1/8" thick chassis (0.125") then that's pretty huge (almost 8ga). Not to mention ridiculous to bend.

[basschops1528]

That's probably why it came out like crap. Not to mention I think a student did it as well. So at 0.0625 (14-15 gauge) that might be ok......? I can see if they have smaller gauges like 12.

[Paul1453]

I think I got my gauge numbers messed up again.   

Steel and Aluminum don't have the same gauge thickness, I found out.

I do remember them saying .09" is minimum for heavier PT/OTs.   

[EKDENTON]

16gauge in steel is .063 and in aluminum it is .050.  Ditto on the .080 being a nice thickness for a chassis. Make sure you ask for bendable aluminum. Some types are tempered such as T6 and others. It doesn't bend like 5052 or 3003 grade.

[Paul1453]

Here are some pics of the quality scraps I got.

I got a number of other larger lower quality pieces too, that may still prove usable.

All for $13 cash from the scrap metal yard.

Full sheets of .09" aluminum are very expensive.   

[HotBluePlates]

Full sheets of .09" aluminum are very expensive.

It is? https://www.onlinemetals.com/merchant.cfm?pid=7130&step=4&showunits=inches&id=240&top_cat=60

About $25-35 for 4 sq ft depending on the alloy.

Myself, I'm fine with paying someone else to provide a quality chassis that I don't have to fold. But I know when the price of a blank chassis is too high.

[Paul1453]

The metal shop near my house I went to told me I had to buy a full 4'x10' sheet.
It was not this thick, and they wanted $160+ after taxes etc.
For this thickness I expected a price over $200 for a 48"x120" sheet.

This could make quite a few chassis' but it was definitely more than I wanted to pay.

I might have to see what that onlinemetals place will charge me including shipping for a standard size chassis sheet.

[EKDENTON]

I can sell the 0.080 5052 for $5.25 sq.ft. includes the cutts. The shipping would be whatever the actual shipping plus a few bucks for the shipping materials. I don't want to do bending though, but i can sell the flat sheet.

[Paul1453]

I can sell the 0.080 5052 for $5.25 sq.ft. includes the cutts. The shipping would be whatever the actual shipping plus a few bucks for the shipping materials. I don't want to do bending though, but i can sell the flat sheet.

I think you have a customer.    
You have a Paypal account for easy cash transfer, I hope.   
I'll send you a PM later.  I need sheets for 2 HoSo56's I plan on building after I finish my Quad 6V6 Plexi.   

[EKDENTON]

okay awesome!

[drgonzonm]

It your willing to accept some standard widths, you can use structural steel studs for your chassis builds.  You can get 16 or 18 ga, If you want a return, get a standard stud, if you don't want the return buy the track. 
Height of chassis 1-1/2  inch.

We have a local manufacturer of hallow metal doors, they work with 14 and 16 ga and rarely 12 ga.  They have the equipment to custom punch any chassis layout, plus any bending. 

[G._Hoffman]

I've used a bunch of different chassis, and the .090" aluminum ones were about as thin as I'd want to support transformers. 

My favorite one at the moment is the 18 or 20 Gauge steel I used for the AC30 I'm finishing up.  If you don't need sides, you can make do with the $60 brake I got from Harbor Freight (there are many other sources!).  It is possible to make it work as a box brake, but the results aren't ever great.


Gabriel

[basschops1528]

Couldn't you cut and tack weld sides if you needed em?

[G._Hoffman]

Couldn't you cut and tack weld sides if you needed em?

If you were a welder.  I'm not, and I don't really need `em.  Or bend sides and spot weld them.

I really do like the steel chassis, though.  It has weight, and feels robust in a way that I never really felt with aluminum chassis, even quite thick aluminum chassis.  I also really like drilling all (or at least, most) of the holes in a flat piece of metal, instead of in a bent piece as I always had to do with the pre-bent aluminum chassis I've tried.


Gabriel

[basschops1528]

I found a local supplier that sells all sorts of aluminum, including different grades of sheet. Could someone tell me from the following list a brief description, your opinion for use in chassis', and if it can be vent by the harbor freight brake?
6061
2024
3003
5052
1100
7075

[Paul1453]

ekdenton has recommended the 5052 as bendable.

As this is all new to me, I'll take his word on that. 

[EL34]

.125" 6061 aluminum is thick and sturdy


That what all my amps used


Your chassis came out bad because the person bending the metal did not know what they were doing


Find a shop that knows how to do it properly


.090 aluminum is a good thickness for most chassis

[basschops1528]

Thanks Doug! I feel established now that you've commented on a thread of mine   

[EKDENTON]

On that list 6061, 5052, and 3003 are bendable. 3003 and 5052 is weldable. The others I don't recognize. If the grade starts with the letter T before the number, that designates that the aluminum has been tempered. That type may break before it bends to a ninety degree bend. The grades above are good. I'm liking the .080. The next size up like Doug said is good. Once you get thicket than that....like 1/8" it is probably overkill for a Marshall size chassis and harder to work with.😊

[basschops1528]

I ended up buying the harbor freight bender which can do up to 17 gauge steel in the documentation. The thing looks pretty solid but I suppose its never good to push it too far. I bought some alumiweld to do side pieces. I will let you guys know how that works out with pictures

[G._Hoffman]

I ended up buying the harbor freight bender which can do up to 17 gauge steel in the documentation. The thing looks pretty solid but I suppose its never good to push it too far. I bought some alumiweld to do side pieces. I will let you guys know how that works out with pictures

Try a steel chassis instead of aluminum.  You'll have to do something about rust, but they really are nice and solid!

By the way, brakes ratings tend to be for a sharp radius bend the full width of the brake.  A larger radius (made by pulling the hold down bar back from the corner) or a piece which isn't as wide allows you to use a heavier gauge steel.  I've used 16 Gauge on my cheap brake without any major issues, mostly by having a 1/2" radius to the corners (there are on-line calculators for setting up fairly precise corner radius).  You do get a bit of a boxing to the side, but just a bit.  I don't know that I would want to go any heavier than that, but you probably could if the part was narrow enough.


Gabriel

[basschops1528]

Could you post an example of this 1/2 radius and what you meant by "boxing" and "narrow"?

[G._Hoffman]

Could you post an example of this 1/2 radius and what you meant by "boxing" and "narrow"?

Sorry, auto-correct.  I meant bowing!  The side you are bending up will bow out just a bit.

By radius, I mean the edge isn't sharp - it has some size to it.  Like so:




By narrow, I mean it doesn't go the full width of the brake - If you have a 30" long brake, you can bend thick material if it is only 10" wide.


Gabriel

[basschops1528]

When you say 1/2 in corners, you don't mean the inside radius or arc itself, right? I sed to sharpen skates so I think I know what you're talking about. It's not a linear measurement like length or width.

[tubeswell]

I use  between 1mm to 2mm thick ally on all my DIY chassis builds, depending on the size of the chassis required. 1mm steel is the same strength-wise as using 2mm ally but steel is much harder to bend, drill, punch etc. Ally is harder to weld and you can't solder to it. Both types have different shielding qualities.


If you don't have your own folding brake, then get stuff made up at a local sheetmetal engineering workshop - most commercial places will do small jobs, and if they are really in the game of producing fabricated sheetmetal, they will know how to do a good job.

[G._Hoffman]

When you say 1/2 in corners, you don't mean the inside radius or arc itself, right? I sed to sharpen skates so I think I know what you're talking about. It's not a linear measurement like length or width.

I'm not sure that this brake is capable of enough precision to really discern between the inside radius and outside radius.


Gabriel

[basschops1528]

Gabriel, do you have a couple bent pieces around that you could do a close up of so I can see the the actual curve? And maybe a note with the thickness/gauge for each?

[basschops1528]

Also, would anyone know what types of steel work best for bending? I'm on a website with a lot of different grades/numbers...

[G._Hoffman]

Gabriel, do you have a couple bent pieces around that you could do a close up of so I can see the the actual curve? And maybe a note with the thickness/gauge for each?

I really am not an expert at this, but you can see the kinds of things I've been able to do in my thread on my AC30 chassis, HERE.  There are several pictures there where you can get an idea of how much radius I ended up with.  I'm pretty sure that was all 16 gauge, but it might have been 18. 

The basic idea is, the further back you put your press plate, the larger the radius will be.  (You can see a manual for this brake at Grizzly's website, HERE.)  For a very tight bend, you put the press plate back from the moving plate by the thickness of the sheet you are using.  I've used the bend allowance HERE to calculate bend radii, but again, this brake is not very precise.

Also, would anyone know what types of steel work best for bending? I'm on a website with a lot of different grades/numbers...

Nothing hardened, and probably nothing stainless (which tends to brittleness).  I've always just bought mild steel from the home center (at my local, they call it weldable steel). 


Gabriel

[basschops1528]

Just finished a custom chassis tonight! I made my first chassis out of .080 aluminum and it actually came out alright considering it was my very first. I used a jigsaw to cut everything which I will never use again, I bent the metal myself in my "Bay Shipping" Bending Brake, and bonded sides to it with alumiweld. Several mistakes: The top dimension turned out too long and the front/rear panels were slightly shorter than expected; the length was spot on however. The sides fit decently but the weld broke on two of them when I tried to manipulate a panel. The front and rear were both bowed out and in, respectively. I forgot to put flanges on the open side for mounting a back panel (this is a Revibe project) so I will need to braze some on. Overall, I think It came out ok. In the future I will correct my mistakes and hopefully build a better project.

[basschops1528]

More

[basschops1528]

still more...

[basschops1528]

Last two!

[Justa]

Many years ago I worked in a sheet metal shop.  We always used 5052 for bendable chassis's and used 6061 for flat panels only.  6061 is strong and bendable but tends to fracture when you bend it.

[Paul1453]

I'm hoping my 1st attempt at making a chassis with my metal brake will turn out as well as yours did.   

One thing I did notice was that you didn't make any mounting lips on the edge of this.
Was that a 1st time oversight, or do you have a different plan for securing this to your housing?   

[basschops1528]

You know, sometimes even engineers forget a step when relaying to assemblers lol. I forgot that bend, but I may have not been able to do it anyway. I intend on making another box and selling this one. If I use it, I will add on small wings where needed

[G._Hoffman]

You know, sometimes even engineers forget a step when relaying to assemblers lol. I forgot that bend, but I may have not been able to do it anyway. I intend on making another box and selling this one. If I use it, I will add on small wings where needed

Angle iron (or, in this case, aluminum) is your friend.


Gabriel

[basschops1528]

that's an interesting idea! The Depot sells small pieces of 90* aluminum.

[drgonzonm]

I worked at a hollow metal frame and door company that manufactured frames and doors.  We made doors and frames out of paintlok type sheets, corten sheets and 300 series stainless steel.  The 400 series will fracture.  (check it with a magnet, if a magnet sticks you can probably bend it). 

If you can live a chassis that is 1-1/2 high, 3-1/2, 4, 5-1/2, 6, 7-1/2 or 8 inches wide, then use structural metal studs.  (the curtain wall studs are just too thin).  You can use a crackerjack box welder with 60 series rod to put sides on it.  (16 gauge is a challenge for beginners).