1/8" Aluminum for top plate?

[Sherman]

I'm almost finished gather materials for my SE KT88 monobloc project and am now deciding on the chassis. My plan is to mount everything on aluminum sheet and place that sheet on a base.

It appears that the aluminum sheet will have to be about 11x12" minimum for the layout I've (mostly) decided on.

Would .090" sheet be thick enough or would I be better off going with .125"?

[Tom Bavis]

I think either would require bracing - add an aluminum angle or channel underneath that catches at least some of the mounting screws of the transformers.

[Peter Menting]

I have used .125" Aluminum for a 12x13 plate on my Dyna 70 Clone without bracing and had no problem with sagging but the tube sockets come very close to being flush with the plate which made me uneasy, although I have never had any shorting problems.

I would suggest something like .1". How heavy are your trannys?

Pete

[jackinnj]

there's a EBay seller who specializes in aluminum -- it's in the Industrial/Metalworking section -- very good prices --

in Chicago you should be able to find this stuff very inexpensively -- if you want to visit a scrapyard.

[purplepeople]

When strength is a concern and motion is not, there is no doubt that bigger is better.

Do you know the alloy? It might be strong enough in the thinner gauge sheet. Since aluminum comes in dozens of alloys, each with it's own structural characteristics, the thickness of the material cannot indicate how strong or rigid it is.

:)ensen.

[markp]

A piece of T6061 aluminum 1/8" thick that size will support the weight of a man. Find a metal dealer in your area and go look at his scraps to find a good plate. It is about 1/3 the price of having them cut you a new sheet. If it is not the right size it is still cheaper to have them cut it for you. If you have a table saw with a carbide blade you can cut it yourself(yes you can cut aluminum on a table saw).

[Geek]

I have used 1/8" 5052-H32 (much cheaper than 6061) and I had to use a 2-ton hydraulic jack to bend it into a chassis. Heh, I had clamped 4" of it and was standing (and hopping) on the remaining 8" and it would not bend. And I'm 250 LBs!

[jackinnj]

Originally posted by markp
If you have a table saw with a carbide blade you can cut it yourself(yes you can cut aluminum on a table saw).

Wear ear protectors !

I am in the process of building a modular chasis -- the idea comes from taking apart various HP and Krohn-Hite equipment -- as I have a little milling machine it should be very easy to use 0.093 aluminum sheet for the sides, top and bottom, sliding these into the milled rails:


[p]

[Sherman]

Originally posted by markp
A piece of T6061 aluminum 1/8" thick that size will support the weight of a man...

The sheet I'm looking at is in fact 6061 alloy. I can have it cut to the size I need for no charge but I'm thinking of also getting a larger sheet to have available for future projects so knowing I can cut it with a table saw is nice.

I will get the 1/8" today! (Now I just have to break down and order the iron. Still waffling between Hammond and James OPTs.)

[rcavictim]

Must add to what Jackinnj said about ear protection. Wear EYE PROTECTION!!!

If you are careful a hand held power saw with a carbide blade can also do a good job on thick aluminum sheet. It is almost amazing how good one can cut 1/2" thick aluminum plate this way.

BTW, I suggest you mill the tube socket holes. This 1/8" aluminum in the harder alloys is very hard on the bolt in draw punches. If you must use a draw punch, use plenty of oil on the bolt threads and also the cutting surfaces of the punch.