Cross drilling a rod or tube

I am making some bushes about 1/2" long by 1/2" dia which need to be cross drilled. They sit nicely in a V block, its just that the clamp is too high and close to the hole so it gets in the way of the drill chuck.

I could make or buy some really small V blocks but I feel its the wrong solution. The solution I am after is a low silhouette finger that runs fore and aft along the V axis with some clamping arrangement. But the only solution I can think off requires many fingers to span the rod size 1/8" to 3/4", if the finger is to have a V in it to centralise the clamp end on the top of the work piece. If no V is machined in the finger then some other stabiliser would be required to stop the finger slipping down the side of the rod as the clamping pressure is put on the finger.

If I ditch the V block and use two plates with Vs milled in each, so there is lots of room for clamps and jacks, then I need an assortment of thickesses to cope with the different depth of groove for different diameter rod.

Unless someone can suggest a better way, I'll just grab them in toolmakers clamps and clamp the clamps down to drill the bushes,

Frank

Hi Frank,

Consider making a simple drilling jig from a short piece of 25mm square MS. Setup in the 4-jaw and drill and bore to a good fit on the bush you want to drill and fit a clamping screw to stop it rotating. Then drill a pilot hole on one square face. That is how I drill thin wall ali tubes.

Johns idea is good even though making a new drill jig for each size seems more work. In practice most folk use few sizes so its not long before you have jigs for every size you use. Its not the way I work (skim flat where drill is to go, edge find on rod, set to centre, spot drill and drill) but it was the advice I was given by an experienced worker many years ago which, in retrospect, I should have followed. Would probably have accumulated jigs for all the sizes I use 20 or more years ago if I had.

My adviser advocated a nylon screw for clamp duties to prevent marking the work but an ordinary screw with a copper slug underneath fitted just tight enough not to fall out but still able to move a fraction ought to do equally well.

Clive.

If they are rigid enough to clamp down into a vee block then aren't they also rigid enough to simply clamp in a machine vise between their two (flat?) end faces? Perhaps I'm missing something.

Hi Frank

John and Clive are correct in making a jig only takes a few minuets and works perfect as long as its held tight and not allowed to turn, I have made several sizes over the years.

Stan

If you have a lathe, this would be a good use for a vee pad centre in the tailstock. They go under different names but RDG have them in stock as "2MT Vee Tailstock Adaptor" for about £15. They are ideal for jobs such as yours.

George

Frank

These links have what you are possibly looking for ...

**LINK**

**LINK**

George

Yes agreed. I often cross drill stuff in my milling vice. Not a fan of V blocks for stuff like this but I have made a small cross drilling jig for small stuff for my finger plate.