Thanks, Vince "Reasonable Use" might allow us to make use of some of the data, without actually wholesale-copying all of it. I think your numbers and thoughts will help the group. An IEEE membership is quite expensive- been there before! Leonard From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Vince Mulhollon
Sent: Tuesday, July 15, 2014 9:43 AM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:4591] Oak S100 card cage On Monday, July 14, 2014 9:14:46 PM UTC-5, mathman wrote: If you have the dimensions for making a card rack/ guides, might there be a way to pass this info to the group?
As I researched this topic for a reply I was surprised to discover the copyright owner still wants $36 to read the 40 or so pages. I had initially used the power of google to find IEEE Std 696-1983 in pdf and assumed it was free... So thats annoying. Anyway I have obtained a paper copy.
You want figure 16 "Board Mechanical Parameters" on about page 38. The right hand side gives all the rack specs:
Spacing is 0.75 inches +/- 0.01
The distance between the deepest part of the slots is 10.325 (typo, probably 10.033) inches to 10.045 inches.
Slots have to be wider than 0.071 but can't be wider than 0.080. A bit wider than 1/16th inch boards which are 0.063
Theres a trick to cutting wider slots on a table saw involving some trig and cutting at an angle. Its a lot easier to put a semi-precision shim underneath one edge of a sacrificial board than to mess with the angle of the miter. Need a sacrificial board acting as a new cutting edge because the pivot point "radius" of the trig puzzle means the shim thickness would have to change as you cut successive slots. Wouldn't need that on a "shooter board" which is like a permanent 90 miter but a tray, kinda, etc. Its all a pain, but quite possible. Needs some good clamping. Of course most folks table saws aren't in perfect alignment (neither is mine) so test cuts might very well be close enough to add a mere 7 thousandths of an inch or whatever to a 1/16th blade. I think I've seen some peoples table saws that might have trouble only cutting a 0.080 using a 1/16th blade...
So anyway, yeah, it takes time and lots of measurement and work not just crosscutting 18 times as fast as I can like I'm making a bookcase or something. But I think I can do it...
Slots have to be between 0.100 and 0.170 deep.. I would aim for the 0.100. I have some measurements to make on my board collection to make sure they fit. Note this doesn't simplistically mean you only have 9.8 width to design in, because thats 0.17 inches from the bottom of the 10.0325 deep slots, or a worst case scenario of only 9.69 inches wide? I think? Slot depth is quite a problem and I'm going to make some precision measurements before I cut wood. There's the official standard and then there's real world.
I considered cutting plastics but 1) static electricity 2) imbedded stresses, from experience with cold rolled steel machining cutting slots will release some embedded stresses causing some pretzel-ing. Will it be better or worse than CRS and better or worse than long term wood warping? Guess I'll find out...
I am worried about the corrosion issue. I may very well end up buying plastic 1/16th wide card guides and sticking them in precision located and cut wide dados in the wood. That would give me chemical compatibility. Also I could probably "customize" a plastic card guide for an individual board if I had to. Or I could use the milling machine to mass produce the inserts. Or not use oak which is pretty corrosive and stick with pine. Doesn't the soldering rosin in our solder eventually come from pine trees? So I think pine would be chemically compatible with circuit boards.
The problem with laser cutting suggestions is its precise and accurate especially for wild shapes, but its expensive and very slow, like a week to get test pieces, and I already have all the gear to make a straight cut in a piece of wood just minutes after deciding to do it. So I'll probably spend some quality table saw time, probably on some pine boards.
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