Enlarging existing chassis holes (correctly)

[Bdimb]

The chassis I’m using for my 5E3 project has holes for pots where I need larger holes for switches and fuse holder. I guess with enough effort I could use (abuse) some drill bits to get to desired diameter, but what are some other, wiser options? Google found some reamers that look like they’d do the trick. I have only ever used wood reamers and with them I can use one for various size holes. Are chassis reamers the same or does each one just ‘do’ one size?
thnx

[sluckey]

Hand reamers work very well in chassis material. I have one that reams up to 3/8" and another that reams up to 1/2".

A better more powerful and more precise alternative would be a step bit. They are easy to use even in a hand drill and usually step in 1/16" increments.

[Dynaflow]

 Like Sluckey said, a step bit, this tool will come to be your best friend for chassis drilling. I think the one I picked up I got from Home Depot:



Regards,

Dyna

[Bdimb]

Thanks gents! Stepbit (unibit) seems to be the weapon of choice, and if I can get at the Home Depot it saves me S&H and time.
Like I admitted on another board I have a brand new one at home; $5 garage sale find that won;t fit my drill; real bargain eh!

[jhadhar65]

I've got about every round Greenlee made, so I use those.  Very expensive, though.  I want an IEC punch, but those are disgustingly expensive.

[Direwolf]

Yeah, I've got most of the Greenlee punches that I need. I'd love an IEC punch but, you're right, it is disgustingly expensive.

[G._Hoffman]

I want an IEC punch, but those are disgustingly expensive.

Not that I can afford one, but where can you get them?


Oh, and along with the step bit, get yourself a deburring tool.



Gabriel

[jhadhar65]

I guess I shoulda bought it when I had the chance... I can't find one at all now.  The one I remember was 3/4"x1" and was somewhere in the neighborhood of $400 - $500.  I thought I saw it in a catalog, like Allied Electrical or Digikey or Mouser.

Maybe we can get Doug to start CNC'ing them.  He'd make a fortune, I'm quite sure.

[Direwolf]

I've seen them on the Greenlee website and I saw one on eBay. They are pretty rare as far as I can tell. Even a square one is $300-400 bucks. I'm still looking for one of them there square drill bits!  ;D

I did find this though. About the middle of the page there are some rectangular hole punches. Looks like model CP-7 would be closest to IEC.

http://www.newportus.com/products/AccCalib/PnlPnchs.htm

Here's a Greenlee that's close:

Greenlee rectangular punch

All are pretty pricey.

[jhadhar65]

I'll bet that CP-7 would work.  I saved the link until a little stimulus comes my way.

(PI or Hollywood?)

[Direwolf]

PI

[jhadhar65]

Hollywood - 1035 in 1987.

[Direwolf]

PI - 3003 in 1985.

[Dynaflow]

PI = 3.14159265   ;D


Regards,

Dyna

[Frankenamp]

Grainger or Mcmaster-Carr have the greenlee's for disgusting prices...
Harbor Freight may be cheaper than Home Despot (they come from the same commie factory) so get whats cheaper. The Unibits ^tm are US made and much more expensive.

[billcreller]

I've been using the cheapie step bits from Harbor Freight.  One set they have goes up to at least 1 3/16", which I used for a cap can hole.  I have some chassis (knock-out) punches, but not many useful sizes for amps.

[bigsbybender]

As for the Uni-bits (step bits) I use an Irwin that goes to about 7/8" and I have a Sears Craftsman labeled one that does a 1". Home Despot has a Greenlee that goes much larger. The Craftsman one actually cuts faster than the Irwin as it has two cutting surfaces instead of one. I've had the Irwin for longer and used it alot in auto repair in restoration in addition to cutting amp chassis and it works as well as the day I bought it 6 or 7 years ago. I've had the Craftsman labeled one for a little over a year so I can't form a longevity opinion on it, but it's held up very well so far.

j.

[Tiny_Daddy]

I got a small Milwawkee hand drill with it's strangely-large 3/8 chuck. A little web searching turned up an identical 1/2 inch replacement chuck. I use this to turn a large uni-bit from ebay. But if you are enlarging that chassis hole to 30mm be sure to clamp the chassis, or have someone hold it down while you drill. Then use a round file to clean off the burr.

[G._Hoffman]

Then use a round file to clean off the burr.

Get a deburring tool - it's cheaper than a file, works faster, and does a better job.  It's one of my favorite tools when doing any kind of metal work.



Gabriel

[Tiny_Daddy]

Which deburring tool are you using? Sounds like I need one.

[G._Hoffman]

Which deburring tool are you using? Sounds like I need one.

I think it was $6 on McMaster-Carr.  Unfortunately, I can't link directly to their site.  Doesn't really matter though.  You can get one at Sears, if you want, but if you go to McMaster-Carr and type deburring tool into their search engine you will find what you need.


Gabriel

[Tiny_Daddy]

OK I am looking at McMaster here:
http://www.mcmaster.com/#4289a71/=1wwk3p

So do I get standard or heavy-duty? Telescoping or non-telescoping?

[jhadhar65]

(TD - How did you hyperlink to that page?)

[Tiny_Daddy]

After finding the page, I just cut and pasted the address from my browser.

[PRNDL]

There's an inexpensive chassis hole punch kit

Punch Kit 5 piecepadIncludes 5/8, 3/4, 11/16, 1 and 1 3/16 inch punches, covers popular tube socket sizes (the 1 3/16 size works fine for standard 1 1/8" size octal sockets).Punches up to 18 ga standard steel and .068 aluminum or copper, works on standard Budd and Hammond hobby chassis.
pad
$69.95

http://store.triodestore.com/toolmarkit.html

[G._Hoffman]

OK I am looking at McMaster here:
http://www.mcmaster.com/#4289a71/=1wwk3p

So do I get standard or heavy-duty? Telescoping or non-telescoping?

Scroll down to the bottom of that page - the standard duty one in the last section of that page is the one I have.



Gabriel

[Tiny_Daddy]

Thanks I'll get that and a carbide blade too (wonder if it will break if dropped on the floor....)