drilling profile rails

[Clive S]

My plan is that when everything is assembled in place, moat made, etc I will put long bolts into the holes covered in grease. After the pour, when things are nearly set I'll take them out.

Don't forget you will get the epoxy rising around the bolts like the sides of the moat will so will have to be shaved off .

[Boyan Silyavski]

Using a small drill press, the smallest ones, you could turn the base 180 degrees and clamp it to the table . Then drill, then move and so on.

But honestly you can not skip the drilling and tapping. I used a nice pro Makita 2 speed Rotary drill, new drill bits and Big Gator Tap and Drill Guide Block. Plus a clamp or two.

Using the Big Gator Tap and Drill Guide Block when tapping was a big help and i did not break a bit. Quality cordless drill with a machine tap also will help speeding the last part of the process.

I also use transfer punches as above.

Also drilling before mounting the rails against a straight edge ??? The acceptable error is not so much as you imagine it. If you do not do things precisely from the start you will have to open some rail holes further.

[reefy86]

Thanks guys really appreciate your input, will look for a decent pillar drill that i can clamp :)

[njhussey]

Well I've stopped buggering about and started drilling and tapping the first (reference rail) rail. I put the two reference sides of the rails together , as suggested, and I couldn't get a 1 thou feeler gauge to even start to go between them.

I've drilled and tapped about 7 holes so far with my set up as below and all the holes are nicely central with approx 1/2mm each side of the hole so plenty of room for any adjustment if needed.







Tooling plate is on order but will be 5-6 days and now going to order a straight edge from the same place as Silyavski in Germany to make sure that there isn't any (or negligible) twist in the rails.

Thanks for all the comments and suggestions guys!

I've got a FERM pillar drill and I clamped it to the bed of my machine to drill the holes. I also used a DIY jig to ensure that the holes were in the middle of the rail hole.....then hand tapped the holes using another jig....