For me this is a voyage of discovery (as usual!), so I had no pre-conceived drawings, I just measured up the pillar drill and looked at some off the shelf jigs which you can buy. Some links were provided in here from others plus plenty of tips.
My jig is about 24"x12" or 600x300mm.
I randomly decided on where the two parallel T-tracks should be located based on where the three securing bolts are located (these obviously can only be lined up with the slots in your metal pillar drill table). I don't think it matters too much where these two parallel T-tracks should be placed as long as the fence slides back and forth freely, i.e. they are perfectly parallel.
As I said the base is about 27mm thick and I think that this really helps with strength. I'm sure you could source some of this chipboard from kitchen worktop places and buy offcuts. I'm sure some of these sheds sometimes get rid of their offcuts or even talk to some kitchen installation companies they are bound to have an offcut which they will just chuck in a skip.
I agree with Steve's comments, this is a difficult jig to get right for all eventualities. As I have been making this I have stumbled across further problems and I am sure this list will grow. But you have to start somewhere! The holes I drilled for the sliding fence were too close to the T-strack mounted in the fence, this meant that the adjustable stop blocks could not slide past one or both fence fixing knobs which project out of the top of the fence. I have now drilled further holes further back towards the back of the drill.
The back edge of the fence where the floor standing pillar is located also now requires to be cutout of the fence in a semi-circular shape so that the back edge of the fence fits around the pillar when the fence is pushed further back. This allows for a larger depth of cut from fence to drill bit.
I have made some adjustable fence stop blocks (x2), cut the rectangular recess out in the centre of the jig for a replaceable cutting block and still need to cut the semi-circle, but otherwise it is complete (as far as I am aware at the moment, time will tell!). I may make a thinner back fence or even a taller fence as required should a job require it.
I also spent most of Sunday making an adjustable rectangle routing aid! I didn't want to just make a one off rectangular recess jig for a specific sized rectangular recess. So I thought I should make an adjustable one out of T-track. Not so easy! This took some head scratching, now I have dandruff as well as wood shavings on the workshop floor. You can see it in the pics below, but the router bit (a straight bit with top mounted bearing) has somehow taken a wee shaving off the bottom edge of the T-track on the inside of the jig where the hole was being cut along the periphery. The jig is also difficult to square up but this may be due to my poor hand filing of the ends of the T-track where they meet another piece of T-track. Given some patience it works ok, but I still don't like overhead routing with this kind of setup as you just can't see anything.
Feel free to comment...
cheers
Steve
