Horizontal boring using a power drill

I needed to make deep, accurate holes for the drilling machine described in (instructable currently being written) As the step to do this was so long, I decided to put it into an instructable of its own.

The basis is one of not having any machine tools, unless you count a power drill, and needing a high degree of accuracy.

I took ideas from this instructable: http://www.instructables.com/id/Concentric-Drilling-with-a-Radial-Arm-Saw/ and the 'Fonly drill (http://www.btinternet.com/~two.mm/articles/fonly/fonlydr.htm)
to set up my battery drill to make the central holes in my square bits of wood for the headstock of the drilling machine.  The details will vary depending on what you have available.  I discovered in the process of doing this that my drill is slightly wibbly-wobbly. *Sigh*.

You are going to end up with a long bed, with the drill mounted horizontally at one end, a retaining strip along one edge, and a sliding carriage to hold the stock.  I managed to achieve tolerance of 1/32" over about a foot with this setup, though I'm sure you could do better than this.

Update:
I eventually used a long piece of wood to make a bed for the whole thing, with a strip attached to the back of it for the stock-holder to slide against.  The drill holder was screwed down to this.  I was able to work much more accurately this way.

Problems:
I discovered that when end-boring a piece of wood, especially with a standard twist drill, the drill tends to try and follow the grain rather than the direction you are drilling in.  This set up just isn't sturdy enough to overcome this.

Successes:
I was able to drill out the end of the long 10mm bar shown in some of the pictures by making a stock-holder that could hold another drill chuck, mounting a drill in that one, drilling a mid-point holder to stop the bar wobbling, and mounting the bar in the drill.

Failures:
The wooden stock I originally intended to use turned out to be diamond shaped rather than square, and impossible to hold consistently in the holder.

Step 1 Materials and tools

* Straight piece of board to make a bed at least as long as the piece of stock you want to drill plus the length of the bit
* Strip of wood to make a runner along one edge of the bed
* 4 pieces of plywood - maybe 5mm - to hold the drill and the stock
* Piece of board a bit shorter than the body of the drill
* Thick piece of wood to attach the boards which carry the stock.  If using hole saws, this needs to be no longer than the length from the drill collar to the cutting edge of the saw that makes a hole to fit your stock, plus twice the thickness of the plywood.
* Screws and nails to hold it all together.
* Hammer
* Screwdriver
* Long piece of straight bar or dowel

Comments

[glorybe]

The run out that you mention is all too common in both hand and drill presses. Part of it is built into the economy of the product but much of it often comes from the strain caused by harsh usage of the drill, hard or inconsistent materials and particularly from not having the right drills, low quality drills or hand sharpened bits that are less than perfect. Some of the cheaper bit sets have such poor metal that they can't even drill soft woods easily and getting more than one hole drilled with such a bit is unlikely. The cost of a good collection of drill bits can easily pass the cost of a good, pro quality table saw.

[throbscottle]

What an interesting and informative comment! Thanks! I'm glad it's "not just me".