chassis

[EWBrown]

I guess I tread the middle ground, 9/64 for #6 holes, 11/32 for #8.
Greenlee punches, 1/2, 3/4, 7/8 and 1", plus another brand 1-3/16 keyed punch which is right for some octal sockets, I just clip and file off the little "key" tab to make for a round hole (this was originally to for Allen-Bradley industrial pushbutton switches and indicator lights). I also got one of Uncle Ned's punch sets, OK for aluminum, brass, copper, some plastics, but not up to the job on all but the thinnest steel, as the metal is not hardened like the Greenlees. Any other size holes, I bring the chassis to work here and use their punches or hole cutter bits. The ball bearing "slug busters" work great!

If you need larger or odd size rectangular cut-outs, a nibbler tool is the way to go. Greenlee does make square punches but they are made of pure unobtainium.

The Mouser red and green rocker switches fit perfectly into the 20 mm hole, though a little plastic "locator ridge" has to be trimmed off the switch.
A 3/4 dia hole is too tight for these, as I found out the hard way. I got the switch out, but it was ruined. Now I just use NOS or "rescued" bat handle toggle switches, that fit a 1/2" dia hole. I bought some new "made in China" ones from Jameco, they were crap, but then they were also low cost. Lesson learned...

/ed brown in NH

[EWBrown]

Thanks for the pointer, I've seen these at the local hardware store, but they were pretty expensive, the E-bay prices are about half. I just sent off for a #1, #2 and #4.

/ed brown in NH

[tubes4hifi]

I've built quite a few amps in the past few years, and the chassis is always the part I hate. My first DIY ST35 took me about 3 hours of drilling, punching, nibbling, and etc. It came out nice, but when I figure the time and frustration I decided it was worth the $50 to have a custom top plate made. BTW, they can be almost any color.
Check out the photo of my newest at:
www.tubes4hifi.com/st35.htm
I haven't figured out to post photos on this forum yet or I would just put it here.

[Shannon Parks]

I've built quite a few amps in the past few years, and the chassis is always the part I hate. My first DIY ST35 took me about 3 hours of drilling, punching, nibbling, and etc. It came out nice, but when I figure the time and frustration I decided it was worth the $50 to have a custom top plate made. BTW, they can be almost any color.
Check out the photo of my newest at:
www.tubes4hifi.com/st35.htm

Tubes4hifi - how thick are the top plates and what is the material/finish? Pretty slick! Also, what (horizontal) power transformer are you using?

I haven't figured out to post photos on this forum yet or I would just put it here.

Hit the [Img] button, type the link, then hit [Img*] again. Like so:



Shannon

[tubes4hifi]

Hi Shannon,
I must again congratulate you on doing such a nice job on the rev C PCBs. Top notch quality, and also the fact that you are doing so much analyzing and testing and troubleshooting, and great forum here.
This top plate I had made is 1/10" thick, can be any thickness, but this was just about perfect for the size and weight of the transformers.
Can be plain or anodized aluminum, any color. I like the gold, and the medium bronze color available is really classic like the old Marantz and Harmon-Kardon stuff from the 60's.
This plate is 12" x 8" so I could just drop it on top of a cheap Hammond chassis, since I'm not a woodworker. Anybody out there that can make nice wood bases please contact me via email or in this forum, as I'm always building amps.
I got the transformers from a Lafayette EL34 amp, they sound great.
Alot of people don't know much of the Lafayette gear was designed by Harmon-Kardon.
Currently working on a custom Dyna ST70 with a 16" x 10" x 1/8" thick plate in a Welborne wood chassis, but they are kind of costly. But I'll have less than $400 into a custom ST70 using all new parts except the transformers, so I'm happy :happy7:
I'm sure some people are going to want my source for the top plates, but since I got laid off from work last week, hope nobody minds if I'm the supplier so I can make $5 on the deal. The reference on the Welborne site doesn't do this type of work anymore.