Drilling my booms

[Gunter]

I need to drill 2 locating holes in my booms, one either end, to stop them turning. These holes need to be exactly in line with each other, so that when I mount the motors, they are all vertical...

Does anyone have any crazy ideas how I can get this accurate with the average workshop tools, ie no milling machine, just a pencil, spirit level and drill??

Thanks, Gunter.

 

[CMonteiro]

I don't know exactly what you mean. But I think the answer is...
Install the motors, in the right place, suject the moters by the shafts,and only then you make the holes on the booms. May be this gabarit I made could give you some ideas. See the photos. I used them to correct the holes with screws that position the arms. Have a look.

View attachment 984View attachment 983View attachment 982

 

[DucktileMedia]

On round tubing, to get a common line down the length of the tube, you can use a piece of angle iron and lay it over the tubing such that the round is inside the "v" of the angle. Then trace a line down the tube where you want to drill.

Then you will want to use a V block on a drill press for drilling precise holes dead center.

 

[jes1111]

What windhorny says. Plus it helps to file a tiny flat area where you're going to drill to stop the drill bit wandering off down the side of the tube. You can also make yourself a jig with some MDF scraps:

Make a V-block that's longer than your tube by gluing/screwing two pieces of 19mm MDF at right angles. Drill a dead-vertical hole in the bottom of the V at one end and push in a peg (or old drill bit) of the same size as your hole will be. Drill one end of the tube, then turn it around and drop the new hole down onto the "peg" - the tube will now be exactly in line for the hole to be drilled at the other end.

Oh, and maybe get yourself a solid carbide drill bit - pricey but they don't bend like the cheapo drill bits do, and they last "forever" if looked after

 

[Bartman]

you could also wrap a piece of white paper around the tube and mark where the end overlaps the paper after its first trip around the tube. Between the end of the paper and the line should be the other side from wherever the end is placed. accurately measure the distance from the end of the tube on each side and you should be able to center punch and drill two holes that are pretty darn close to what you need. Drill in steps though, start very small and step up to final diameter in as many steps as you can stand to make drill changes for in order to keep the bit from going off center from your original mark.

 

[Bartman]

I don't know exactly what you mean. But I think the answer is...
Install the motors, in the right place, suject the moters by the shafts,and only then you make the holes on the booms. May be this gabarit I made could give you some ideas. See the photos. I used them to correct the holes with screws that position the arms. Have a look.

View attachment 1721View attachment 1720View attachment 1719

C
I never commented on your pics but I think that's pretty clever of you to dial all your arms and motors in the way you did.
Good thinking.
Bart

 

[midnight999]

Or make a couple of jigs that are using the pinch clamps with tha hole position on for either end of the shaft, rest it all on a glass worktop or something you know has good level tolerence, level them both up and pinch up the bolts, drill away.

 

[Gunter]

Brilliant, thanks for all the suggestions guys. Just got to work, so I will read through them today and drill them all this evening...fingers crossed!