The BIG 500 series metal work thread! (to be...)

This is a thread that started out as a call for advice regarding the fabrication cost of 500 metal work.
A couple more things related to the general 500 series metal work have come up along the way.
I thought it would be useful to condense everything related to this subject in one place.
Hopefully it will become a reference thread for those looking to make their own 500 series modules.

Original first post below.

Cheers

Mike

_____________________________________________________________________________________
Hello,

I'm working on getting a few L-brackets made for a 500 series version of my 312-type pre.
I have looked into a couple of local metal shops (let's call them SHOP-A and SHOP-B) and haven't yet received a quote from SHOP-A. SHOP-B sent me a quote of CAD$90 a piece for 5 pieces. I was not expecting such a high number. I have another 2 weeks before SHOP-A sends me a quote  :. I am really tempted to go with SHOP-B's offer but feel that it is a bit high for a metal bracket. I have never done anything like that before and would appreciate the input from the more experienced guys.

With that said, I should tell you what the L-bracket is made and whatnot:

- 5052-H32 aluminum
- PEM standoffs (4 places) (the contact from the SHOP-B says that it's not much more expensive than getting countersunk holes instead).
- laser cut profile and holes/cutouts.

What do you think?


Mike

Check out emachineshop.com and bump up your quanity's.

Hi Mike,
maybe you can modify Jeff's L-bracket to fit your needs. It's much cheaper.
http://classicapi.com/catalog/product_info.php?cPath=22_47_55_57_64&products_id=90

Regards,
Milan

It costs a fortune to get anything done from a metal shop in that qty.

If I were to order 5 pcs of my 2U enclosure I would probably be looking at about $500 per enclosure!

If you think about it there is a lot of setup time involved regardless of the quantity and you're locking up employees and machines during that time.

In the end prototyping costs a fortune and you ultimately need to add it to your final mark-up.

Mike

Hey Mike

Check out:

http://www.groupdiy.com/index.php?topic=26996.msg323244#msg323244

DIYed a lot of them this way cheap !!

GARY

kazper said:

Check out emachineshop.com and bump up your quanity's.

Click to expand...

Thanks but I'd rather keep it local (Toronto, Canada). May be useful for more intricate parts though.

moamps said:

Hi Mike,
maybe you can modify Jeff's L-bracket to fit your needs. It's much cheaper.
http://classicapi.com/catalog/product_info.php?cPath=22_47_55_57_64&products_id=90

Regards,
Milan

Click to expand...

Thanks Milan, I don't think that Jeff's bracket will work for me. It's got the wrong hole placements and much too different cutouts.

Echo North said:

It costs a fortune to get anything done from a metal shop in that qty.

If I were to order 5 pcs of my 2U enclosure I would probably be looking at about $500 per enclosure!

If you think about it there is a lot of setup time involved regardless of the quantity and you're locking up employees and machines during that time.

In the end prototyping costs a fortune and you ultimately need to add it to your final mark-up.

Mike

Click to expand...

Thanks Mike. That's totally understandable. I just wanted to make sure that I wasn't getting ripped off here.
I once had a quote for a custom 2U enclosure with PEM standoffs and the whole works for close to $900 a piece for 10!

gar381 said:

Hey Mike

Check out:

http://www.groupdiy.com/index.php?topic=26996.msg323244#msg323244

DIYed a lot of them this way cheap !!

GARY

Click to expand...

Thanks Gary. That sounds like the most cost effective way of getting things done. However, I need close tolerances if I want everything to fit nicely. Laser cutting is preferred here.

Thanks a lot guys.

I will probably go with SHOP-B to get my proto done.

Cheers

Mike

At that price, why do a proto then? A simple aluminum 'L' bracket with some PEMs should top out at $17.50 USD for 25 pieces; about the same as for five pieces quote. In a CAM shop, it's 90% setup; the material is the cheap part. With all the inexpensive and easy CAD software now, you stand a really good chance of getting it right the first time anyway.

I would rather not take that chance. Everything is of very small tolerance and I've not seen the High precision work done by either shop before. They assure me it can be done VERY precisely. 

mikefatom said:

I would rather not take that chance. Everything is of very small tolerance and I've not seen the High precision work done by either shop before. They assure me it can be done VERY precisely. 

Click to expand...

Curious, when you say "very small tolerance", what kind of tolerances are you talking about?

ruckus328 said:

mikefatom said:

I would rather not take that chance. Everything is of very small tolerance and I've not seen the High precision work done by either shop before. They assure me it can be done VERY precisely. 

Click to expand...

Curious, when you say "very small tolerance", what kind of tolerances are you talking about?

Click to expand...

At the risk of sounding like a total metalwork noob, I'm talking about 5 thou give or take.  :-[

At the risk of sounding like a total metalwork noob, I'm talking about 5 thou give or take.  :-[

[/quote]

It's ok, I had a pretty good feeling that's what you were going to say.  +/-.005" is very standard.  Although you might think it's super tight tolerance, it's not at all.  Tight is when you start talking +.002/-.001.  That's when you need to watch out who does it.  Any machine shop out there (unless they're doing it with a hand drill, blow torch, and a hammer  ;D ) will normally do +/-.005 as standard.  +/-.010 if you spec it will be a little cheaper, but not by much.  Once that equipment is set up and zero'd out, the equipment does the rest, really not much difference to the machinist whether you want +/-005 or +/-010.  Just to put it in perspective, in over 10 years I've probably done (best guess), well over a thousand machined parts, every single one .005", no exception.  Even my prototype guy that does it all manually on his mill, still gives me +/005, even when I tell him it doesn't matter haha.  And to be honest, for this type of stuff, I'd be REALLY surprised if +/-.010 wasn't sufficient anyways.  That being said, if you've double checked your math, and the part isn't super complicated, I would go right for a production run and save yourself the money.  Since it's going to be $500 for 5 pieces and $500 for a production run of $25 pieces, you don't have much to loose now do you?

.005" is about as small a tolerance as most shops will agree to. FWIW, laser cutting will be more accurate than that. The bends should be as well but again they will not commit to tighter.

Production metal is a big PIA to deal with. If the mechanical drawings are not in a format the shops are use to dealing with, they will not even bother quoting and will not even let you know.

If this is your first run, make it small. Do not do a large production run out of the gate. Sometimes, your drawings will look great on a computer screen or paper print out, but when you assembled the modules and want to move a switch or pot, you can't cause you got a 100pc and are stuck.

My advice is be cautious so you don't blow a wad of cash on a bunch of aluminum that will end up being recycled. If I ordered my first Rev VP312DI metal right away, I would be eating them now since I had some major revisions. Something told me to hold back and I'm sure glad I did.

Best, Jeff

Check local metalshops that make ductwork for AC supply companies. Go to your local industrial park and door to door the HVAC guys and ask who they use. Get a business card from the HVAC guy and ask if you can namedrop to the metal shop. It's true these fabhouses hate small orders but you can push a few thru at an introductory price because they will assume you'll have a big order for them in the future. Just sound pro. Use phrases like "My clients need such and such" or "It's a small order but I might do a run on these if my customers like what I'm doing."
If you are a new customer and they have a lull between jobs, they will cut you a deal to keep the shop busy.

It worked for me. Perhaps I got lucky.
http://www.rwwarner.com/kaempfandharris/servicescapabilities.htm even made me a free proto, put the finished job outside the door for me to pick up after hours, pay him at my convienence. I never felt more willing to spend my money with a company before. Great service.

   

Post your project/drawings on MFG.COM
Then wait for bids to come in from different manufacturers.

mikefatom said:

I would rather not take that chance. Everything is of very small tolerance and I've not seen the High precision work done by either shop before. They assure me it can be done VERY precisely. 

Click to expand...

Yes, always proto no matter how much it costs.

Even with precise drawings something will come out wrong or not to your liking.

Mike

I see a couple of problems with your specs. You are specifying one of the hardest aluminum alloys you can get. You can't get a sharp 90 deg. bend in that alloy without severe surface cracking. Spec 1003 (I think its that or possibly 1008). Don't use PEMS, use brass standoffs with swage collars. They are easier to apply and cheaper. Punch the holes, don't laser cut. A lot more manufacturers have CNC punches than laser cutters.

I got a quote on this 4 1/4 x 8 3/4 inch panel, punched, bent, electrostatic painting and screening for less than $10 in 100s. There was an additional $175 screening setup charge.

Hi,

Maybe you can use front panel express, the only thing the can not do is the bending, but any local metal shop can take care of that, great and relative cheap for proto.

djn

burdij said:

I see a couple of problems with your specs. You are specifying one of the hardest aluminum alloys you can get. You can't get a sharp 90 deg. bend in that alloy without severe surface cracking. Spec 1003 (I think its that or possibly 1008). Don't use PEMS, use brass standoffs with swage collars. They are easier to apply and cheaper. Punch the holes, don't laser cut. A lot more manufacturers have CNC punches than laser cutters.

I got a quote on this 4 1/4 x 8 3/4 inch panel, punched, bent, electrostatic painting and screening for less than $10 in 100s. There was an additional $175 screening setup charge.

Click to expand...

Not trying to be a jerk but I don't know where you're getting your info.  5052-H32 is absolutely bendable, and is absolutely not one of the hardest aluminums.  It's all we ever use for bent metalwork (if we want aluminum that is).

Thanks guys for all the advice.

You guys are great!

Cheers

Mike

FWIW, I use 0.05” 6061-T6 for my L-brackets. It is a little more expensive than 5052-H32 and harder too. The smallest inside bend radius for the shop I am using is 0.12". Typically, double the material thickness for the smallest inside bend radius is a good rule of thumb. Shops will vary, and some will really pitch a bitch about bending 6061-T6. The first shop I used had an inside bend radius of 0.05" on 6061-T6. I was surprised. I thought they changed material on me but they did not polish the sides and I could clearly see the "6061-T6" mill stamp on the material.

It can generally be a little smaller/tighter for the 5052-H32.

For my layout, the 0.12" is OK. This is another thing that can really bite you in the arse if you are not careful with up front drawings and layouts. All these little mechanical gremlins can suck. 

Jeff