First project, a Hybrid

[timbertoes]

Morning, All.
I am excited to share the beginnings of a Hybrid Tube/SS project.
not much to see yet..  PCB's for power supplies and PA section.
PA is an LM3866 I have had forever.... and the transformer as well.. from an old Alesis Apex Amp kit.

Tube front end.. thinking of wiring it up after the Blues Junior.

[sluckey]

Nice start. I'll be following you progress on this project.

[timbertoes]

thanks :)

I am thinking of using a good 3/4" hole saw "bit" for making the tube mounting holes... advice ?
want to hear a sad story ?  ... ehh, I used to have a milling machine... missing it now.

[sluckey]

I highly recommend using a step bit for big holes. Much cleaner and faster than a hole saw. Even the el cheapos at Harbor Freight make a nice hole in aluminum. Or go to Lowe's and get an Irwin, or step up to the Greenlee (you won't be sorry). Greenlee makes a nice one that goes from 3/16 up to 7/8 for $35.

https://www.lowes.com/pd/Greenlee-3-16-in-Step-Drill-Bit/3122175

I have the small and large Greenlees and have been able to drill every round hole I need in a chassis.

[timbertoes]

thanks, a bit suprised lowes has greenlee brand :)

[jjasilli]

Here's some more tips for making holes in chassis:  http://www.tubecad.com/2017/01/blog0369.htm


I too use a Unibit.  Best used with a drill press. 

[kagliostro]

WOW !!

That is Very Very Cool



But I think it will be very difficult to find it for 100$ on this side of the pond

Franco

[timbertoes]

lol.  its always about the tools :)

[timbertoes]

speaking of tools.... playing around at work..

[silverfox]

WOW !!

That is Very Very Cool



But I think it will be very difficult to find it for 100$ on this side of the pond

Franco

Franco that would be just as hard to find here for $100. I'd snap it up in a sec... I think Sluckey was referring to the "Step Bit" Hole Saw. The Punches alone would be $100.

silverfox.

[timbertoes]

And there is always that one hole....too close to a corner or such, to use the punch.. so back to the drill.

[PRR]

> hard to find here for $100.

The deal is real.

http://www.harborfreight.com/hydraulic-punch-driver-kit-96718.html
14 Piece Hydraulic Punch Driver Kit
Pittsburgh® Automotive - item#96718
Punch holes up to 2-3/8 in. diameter
Material capacity: 11 gauge mild steel, 16 gauge stainless steel
10 ton hydraulic pump
comp at $834.98
Only: $94.99
"Currently, Harbor Freight offers shipping to Canada (excluding Quebec) and Australia only."

30+ good reviews, 2 got ones that did not work.

The target is almost certainly US electrical box punching. I  have been installing 1-1/2" nominal fittings with a 2" hole-saw, and the fit is loose. This box has 1-15/16" which would be better. In fact the punches also have "pipe size" numbers, and electrical fittings come from pipe fittings. The 11 Gauge rating is just about the thickest mild steel we use in electrical boxes.

My experience with tube sockets is that you want several sizes *around* 3/4", because every socket and mount is different. And this punch-set needs a large hole to get started: 7/16 or 3/4". It shines when the box already has a 3/4" hole and you need a big hole at that spot. But in thinner stuff with no hole, a step-drill may be easier (at least to over 1").

Hole-saws work but you MUST clamp a hardwood backup to steer the pilot, and the whole process is violent, liable to grab and throw. That's what I have been doing for 2", but I put it off until I am very rested and calm. (Ohm.... Ohm...)

[kagliostro]

I have a set of cutters like this



not that I've all the available measures, but I've those that have more interest for chassis (may be I've a dozen of different measures)

And also (only) one of this punch




and one of this step drill bit (not a very good steel, but usable)




Franco

[EKDENTON]

I like the step drill, i use one of those often.  I used to have one of the hole punches a long time ago but someone decided they needed it worse than me :-(

[shooter]

until I am very rested and calm. (Ohm.... Ohm...)

I'm glad I don't have bladder control issues yet!

[timbertoes]

ordered two tube amp books to read :)
waiting on other parts.  I am not organized... sigh.
I will probably cut and past sections of the blues junior or the laney 15. or similar..
its all for fun and learning anyhow :)

[timbertoes]

Sooo... I am putting this one the back burner.  I have collected most all the parts I need for a Stout TMB amp, and this is all about Tubes anyway.... lol.