DIY Chassis.

[pinkphiloyd]

On my next build I'd like to try fashioning my own chassis, a new experience for me. If I use an aluminum chassis and stand up transformers so as to avoid having to cut any big square holes, can I get by with, say, a drill press, a good set of bits and maybe some hole saws for the bigger holes like power tubes?

[gui_tarzan]

Start with a cardboard layout first. Find some small boxes for the transformers or make some out of paper, then see if you can figure out the best layout before you start drilling holes in the aluminum. Once you have that done and the layout is good, go for it!

[V2]

I would recommend a step drill bit. You could probably get some cheap ones from Harbor Freight to do the job for about $20.

[martin manning]

I'd recommend buying a quality step drill bit, such as: http://www.amazon.com/Irwin-10235-Unibi ... B0009XJ31A#
This is fine for aluminum chassis and will handle the largest holes nicely if used in a drill press.

[mhartman]

Make sure that you're careful with the step-bit drill on the drill press. On the larger holes (Octal sockets), the bit can catch and send your chassis spinning (hopefully not into you). You want to make sure that you have your chassis secured properly and safely before drilling these.

[Garthhog]

When I am prototyping I fashion my own chassis. I generally buy a blank from Watts Tube Audio (they have a great selection). Cardboard is a good 1st-order approximation, but I like to draw models of them in Sketchup. It is easy to use and much cheaper than PTC Creo or SolidWorks, but it has its limitations. I believe their free demo is very useful... same basic features without add-ins or export capability.

+1 on a quality stepped drill bit. I'd add a set of Greenlee punches. They are pricey, but nothing beats a cleanly punched hole vs chewed up aluminum.

[xtian]

Also, especially with those step bits, it's much better to have a solid block behind what you're drilling. Scrap wood, but with a hole in it so the bit doesn't have to dig the wood out.

[The Ballzz]

All great tips here! A GOOD step bit is crucial. Might I add that Greenlee punches are superior for the bigger holes. A way to minimize the cost of punches is to troll flea-bay. They come & go on a regular basis and you just need to buy from a reputable seller. Very important to make sure the ones you get have a bearing on the draw stud and or get an additional draw stud with a bearing. I just got a 3/4" actual hole size radio chassis punch (for the preamp sockets) with an upgraded draw stud for $30 shipped and a 1 7/32" actual hole size radio chassis punch (for octal sockets) with the bearing , new in bubble package for $34.99 shipped. The seller I link below has an interesting take on customer satisfaction and after actually talking with him I'm confident that he is truly honest in his approach. Scroll down his ad to read his stance:


http://www.ebay.com/itm/121481503005?_t ... EBIDX%3AIT

Just My $.02 & Likely Worth Even Less,
Gene

[pinkphiloyd]

I appreciate all the help and I'm going to look into all of this. Will this press be sufficient? The "machine shop" side of all of this is brand new to me.

http://www.harborfreight.com/8-in-bench ... 60238.html

When I am prototyping I fashion my own chassis. I generally buy a blank from Watts Tube Audio (they have a great selection).

I'm gonna get a lot of the stuff from Watts but I think I'm getting my blank from Angela's amps. I haven't really found a cheaper deal yet looking around.

[Phil_S]

I'm generally not fond of cheap tools and I avoid buying them. If you are really going to get into chassis drilling, you can always buy a better quality drill press later. I wouldn't buy that HF press.

I have cut a number of chassis blanks using an ordinary hand drill, good quality regular bits for smaller holes and good quality step bits for larger holes like sockets. A punch is essential.

If you are patient, you can snag a first quality name brand step bit on eBay for 50% off retail or better. Please skip the no-name brands.

You'll need a 1/2" chuck for the larger step bit. For this I snagged a super heavy duty used Dewalt on eBay for a very reasonable price. The only thing wrong with it is that the trigger sometimes won't turn on with the first pull and that's not a big deal for occasional use.

One thing about using a step bit is that it will often leave a burr around the bottom of the hole. If the hole is far enough from the bend, you can just flip the chassis and clean it off with the step bit (also called unibit.) However, a good layout often positions the socket holes close to the fold so you can't get the drill in there at the correct perpendicular orientation. To solve the problem, IMO, a Shaviv deburring tool is the way to go. Again, these can be found at a discount on eBay.

I use a Sharpie to mark the chassis. Any left over Sharpie wipes off with a bit of rubbing alcohol on a soft rag.

[pinkphiloyd]

That's just it, I don't know if I'll ever want to do this part again so I'm trying to be as economical as possible. I just talked to a buddy at work who has a good press so I'm set there.

[Phil_S]

That's just it, I don't know if I'll ever want to do this part again so I'm trying to be as economical as possible. I just talked to a buddy at work who has a good press so I'm set there.

If he's got a drill press, he's likely to have all the bits you need, too. Be careful. I find the chassis making addictive. I love seeing the spirals of metal coming off the bit.

[M Fowler]

Those Greenlee punches are high quality but most people get the contractor kit which is for punching holes for conduit which is not correct sizes.

I found by googling great punches that were great prices and work excellant.
I use Beldon tube sockets so I got 30mm for the octal and 18.6mm for the noval (9 pin).

I use step bits all the time a must have. For non Beldon sockets I sometimes use the larger step bits carefully then use a hand tool to clean up the edges, not sure what it is called yellow handle with hooked swivel blade on end got it at CED/and or Tubesandmore.com

[pinkphiloyd]

That's just it, I don't know if I'll ever want to do this part again so I'm trying to be as economical as possible. I just talked to a buddy at work who has a good press so I'm set there.

If he's got a drill press, he's likely to have all the bits you need, too. Be careful. I find the chassis making addictive. I love seeing the spirals of metal coming off the bit.

If it does in fact turn out to be something I enjoy I'll invest in some good tools.

[Phil_S]

...then use a hand tool to clean up the edges, not sure what it is called yellow handle with hooked swivel blade on end...

This is a deburring tool. Here's the one I have. It is the bee's knees. I don't know what I did without it. It's quick and very effective.
http://www.mscdirect.com/product/details/05751003
One of these is a must-have if you use a step bit.