Need suggestion of tools to make chassis

Alan0354

Super Member
Hi

I want to get some idea how to and some tools I don't know where to get:

1) A wedge type of handheld hole expander for drilling holes for tubes. For the life of me, I cannot find this here. As a kid, I had one in Hong Kong for opening up holes to fit vacuum tube socket, it's like in this drawing:

Wedge hole expander.jpg

It is so primitive, it has ridges almost vertical sharp ridges as shown, you just stick it in a hole, crank and expand the hole to the size you want. I know they have step drill, I have them up to 1 3/8" diameter, but that's not what I want. Because those step drill on a drill press is very rough, every time it goes down one step, it jot the whole panel. I am drilling 2mm thick aluminum panel, that jot will warp the panel. I need to do it very gently like using this and take the time. Hydrolic press is too expensive to drill a few holes. Please give me either a source to buy this or some other suggestions.

I should have it shipped here 40 years ago. But hell, this is United State of America, how can we have this in Hong Kong and not here!!! Must be too primitive!!!

2) I need to cut square hole for the power transformer onto aluminum panel, what cutting tool I need. I know it might have to be a scroll saw or something. Just want some suggestions. I have been paying extra for chassis that have power switch because I have no means to open a square hole to fit the power switch.

3) I know I can get pcb solder 9pin 12AX7 socket from Tube Depot, anyone make big socket for EL34/6L6 big tubes? I can't find one.


I am contemplate building a tube amp, this is something I never have to think about before.

Thanks
 
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chassis knockout punches do a wonderful job of that. You will need to drill a hole for the screw to run through, but its 3/8" or something, the knockouts typically range up to about 1 1/4". Good ones aren't terribly cheap, and you have to make sure you get them for measured size, not "trade size". Trade size is what electricians use for conduit holes. 1/2" conduit does not use a 1/2" hole. Greenlee makes really nice ones but they are not cheap.

for a transformer hole a good scroll saw and a set of files is probably your best bet.

PCB octal, or standard point to point? Angela.com has both, there are probably other sources. Point to point are probably more common.
 
i think what you're looking for is called a step-drill

not the most precise tool out there, but good for hole embiggening.
 
chassis knockout punches do a wonderful job of that. You will need to drill a hole for the screw to run through, but its 3/8" or something, the knockouts typically range up to about 1 1/4". Good ones aren't terribly cheap, and you have to make sure you get them for measured size, not "trade size". Trade size is what electricians use for conduit holes. 1/2" conduit does not use a 1/2" hole. Greenlee makes really nice ones but they are not cheap.

for a transformer hole a good scroll saw and a set of files is probably your best bet.

PCB octal, or standard point to point? Angela.com has both, there are probably other sources. Point to point are probably more common.
Yes, I know those knock out punches, those are expensive to make a few holes. I don't even know how long I am going to build tube amps, so I am not going to spend over $100 that might not be used after a few holes.

I figure the scroll saw might be it. That, I don't mind spending the money as there are a lot other uses with the saw.



Since you are here, Is it me or are the people in Tube Audio are a lot more closed mind then here and in SS section. I have been asking, making comments here and in SS, people join in and we talk, it's not about right or wrong, it's just talk. I throw out idea, if people don't agree, they can give their opinions and we talk. I know I do throw out wild ideas, I really don't care whether I am right or wrong, just talk and we learn. But over there, seems like people just believe what they believe, when I make some finding and opinion, they are not receptive, they don't even disagree, I got call " entering the twilight zone" " know everything about it"!!!

I did learn quite a bit the last few days building the amp and reading the replies, but to be honest, they really did not give a lot of help. More like they brought up something and I went and research. I did do all the experiment myself, improve the amp a lot by adding the cathode follower. But I have a feeling they even disagree with the cathode regardless I show the result AND said there is a big improvement in sound with the cathode follower. Looks like I have to join DiyAudio for the tube discussion. Over there, you say something, they don't agree, they give their reason, we can get deeper into it. They don't necessary think others are "out there"!!!
 
Yes, I know those knock out punches, those are expensive to make a few holes. I don't even know how long I am going to build tube amps, so I am not going to spend over $100 that might not be used after a few holes.

I figure the scroll saw might be it. That, I don't mind spending the money as there are a lot other uses with the saw.



Since you are here, Is it me or are the people in Tube Audio are a lot more closed mind then here and in SS section. I have been asking, making comments here and in SS, people join in and we talk, it's not about right or wrong, it's just talk. I throw out idea, if people don't agree, they can give their opinions and we talk. I know I do throw out wild ideas, I really don't care whether I am right or wrong, just talk and we learn. But over there, seems like people just believe what they believe, when I make some finding and opinion, they are not receptive, they don't even disagree, I got call " entering the twilight zone" " know everything about it"!!!

I did learn quite a bit the last few days building the amp and reading the replies, but to be honest, they really did not give a lot of help. More like they brought up something and I went and research. I did do all the experiment myself, improve the amp a lot by adding the cathode follower. But I have a feeling they even disagree with the cathode regardless I show the result AND said there is a big improvement in sound with the cathode follower. Looks like I have to join DiyAudio for the tube discussion. Over there, you say something, they don't agree, they give their reason, we can get deeper into it. They don't necessary think others are "out there"!!!
i dunno, my experience here is that people are pretty helpful

step-drills aren't cheap either - you could try to make your own stamp by grinding an edge onto a piece of steel pipe?
 
i think what you're looking for is called a step-drill

not the most precise tool out there, but good for hole embiggening.
Nope....Hand Reamer
https://www.mcmaster.com/#reamers/=19n96c2

3018a4p1l.png
 
i dunno, my experience here is that people are pretty helpful

step-drills aren't cheap either - you could try to make your own stamp by grinding an edge onto a piece of steel pipe?


I agree, people are helpful. I am talking about whether people accept others' ideas in the Tube Audio section. I have no complain in DIY and SS at all, I have been having fun here, or else, I won't be here.
 
they have stepless step drill bits..i have a set, got them somewhere cheap like at harbor freight
 
Yes, those taper reamers are NOT cheap. It was cheap in Hong Kong. Hell I was a kid at the time, I could not afford anything expensive..
 
About the scroll saw, I see 16" for less than $100, is that only 8" radius......can only reach 8" into the panel? That might not be enough. The 20" are very expensive.
 
Low rpm taper drill in aluminum panel won't need much of any cutting fluid, wd-40 works OK. I've also used tapmagic fluid, fairly cheap in small quantities and easy to apply. When using a twist drill (or tapered twist drill) its helpful to sandwich the panel between a couple pieces of wood to prevent warping/tearing the panel if the drill grabs.
 
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