Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: aro on January 29, 2010, 01:19:29 pm
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I want to punch some holes in a Marshall chassis and I found a kit like the one in this link (http://cgi.ebay.com/Chassis-Punch-for-Tube-Amp-Sockets-and-Transformers_W0QQitemZ140334155691QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item20ac9147ab). It says it's for up to 10 gauge steel. Isn't Marshall more than that? If yes, what other punches could I use? I looked online and some punches specify the gauge, some don't. It's hard to know for sure. Thanks.
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I doubt the marshall chassis is 10 gauge steel - 10ga is **very** heavy. That kit will probably work fine - it is a chinese knock off so will probably wear out quick. Do a search on "unibit" and you will see lots of discussion on how to put holes into chassis.
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10 gauge = 0.1345" = app. 3.4mm
All Marshall chassis I've seen are either 1.5 or - for Al - 2 mm thick, so these punches seem to be usable. Work slowly, use plenty of cutting oil : steel can be quite messy to work with.
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Great, thanks.
From what I read I first need to make a pilot hole for the chassis punch. Can I use any metal drill bit for that? I don't have any tools but I have access to lots of them through my band mates, so I need to know what to ask for.
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Yes, any metal bit will work fine. Make sure to use a center punch so the drill doesn't skate allover the place.
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Second the Unibit.....
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OK, I'm totally not the handyman, I'm THE non-handyman, I'm one of the best non-handyman I know. I thought that a punch would be easier to use than a unibit. How do you make a preamp hole, or FX loop holes with a unibit...? There must be more to it than just drilling a hole, especially when I think of the diameter needed for a EL34.
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You can get a unitbit that goes from 1/2" up to 1 1/2" - thats enough for all amp building holes. Not quite as clean as a punch, but it works - and is fast.
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When I search unibit here (http://www.amazon.com/s?ie=UTF8&tag=mozilla-20&index=blended&link_code=qs&field-keywords=unibit&sourceid=Mozilla-search) all sorts of bits come up, including step drill bits. Do they all work for an amp? Do they work with a regular drill?
How do they work; just center punch and then drill away?
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Unibit is an Irwin trademark for their line of step bits - excellent quality, high price.
If you're going to build a couple of amps only, a cheap step bit such as the Neiko is fine.
http://www.amazon.com/Pro-Quality-Titanium-Step-Drill-Bit/dp/B000FZ2UOY/
What kind of chassis are you planning to use? Aluminum or steel? Which gauge or thickness?
Have you access to a drill press? A handheld is barely OK if you want to work with aluminum and inadequate for steel - except if you do four passes using standard drills (pilot hole then larger then larger up to say 3/8", then the step bit).
Holes won't be clean with a step bit, you'll have to manually deburr them. Check manual deburring tools and get a number of different blades.
http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dtools&field-keywords=deburring+tools
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http://www.amazon.com/Pro-Quality-Titanium-Step-Drill-Bit/dp/B000FZ2UOY/
What kind of chassis are you planning to use? Aluminum or steel? Which gauge or thickness?
Right now I want to drill a Marshall chassis. Later on, both.
Have you access to a drill press?
Kinda...but it gets complicated.
A handheld is barely OK if you want to work with aluminum and inadequate for steel - except if you do four passes using standard drills (pilot hole then larger then larger up to say 3/8", then the step bit).
And that's why I was thinking of a punch, it seems to be easier to use.