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X-Y Drilling Job Advice

HighOrder

Plastic
Joined
Jul 27, 2007
Location
Wet
Looking to drill a matrix of 3/32" diameter holes in 3/32" thick GPO3 fibeglass using my bench top drill press. One consists of 280 holes (35x8) and the other 234 holes (18x13). Center-to-center spacing is 0.265" (6.73 mm). I've made two attempts at a jig, essentially using 4 holes in a sqaure pattern such that I can drill the first hole and then use a pin to provide repeatable x-y spacing (drill a hole, slide over one "space" and insert pin - drill hole, rinse and repeat). The jig is an MDF "table" with a sliding fence that I can attach to my drill press table.

Using digital calipers to lay out the small grid and "eye-balling" to drill the pilot holes for the jig, my second attempt at a jig was about 0.08 mm wide on the x-axis giving me a compound error of about 2.7 mm by the time I hit the 35th hole. I'm using a centering bit to drill the pilot holes. I don't think I can do much better eye-balling things, though I might get lucky and hit things close enough at some point. I could probably live with something near or under 1 mm over 35 holes, which I think translates to approximately 0.001" accuracy.

So, I thought maybe I need a cross slide table for my drill press to get to an acceptible level of accuracy. Of course, that set off hours of Internet searching and reading discussions on what's a good table and a bad one. I'm more of a hobbyist in this area, and don't really want to break the bank. I was looking at this table as a possibility:

X-Y Table Assembly | Precision X-Y Table | LittleMachineShop

It seems to fit my parameters, however it is Chinese and I can't find any reviews. Most of the commentary here seems to go against Chinese products, but it's hard to find anything else. Figured this table, a clamping kit, and a combination center/edge-finder. Open to any advice regarding components and my concept for completing this job.
 
There are limits to the accuracy achievable with a cheap bench drill. Look up Starrett toolmaker's buttons and study until you find out how they work. Once your part is precisely located, it should be drilled undersize and bored to size. I would never expect a drilled hole to be within .001".

metalmagpie
 
Get someone to make a jig for you. You don't have the right equipment to do it accurately enough. If you only have one or two parts, have someone else make it and save yourself time and money.
 
Thanks. I'll look into those buttons. I had a jig made for me by a board member here a few years back that I still use today to drill out small metal parts. I'd be open to that as well. Any additional thoughts/advice will be much appreciated.
 








 
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