Jig to drill a 40" bar with a 13" bench drill press

[Marco Bernardini]

I'll have to drill the head of some 40" (1 metre) aluminum bars with the ubiquitous Cheapex brand 350W 5-speed bench drill press, a close relative of the Baby Grizzly, having just a 13" space below the chuck.

To cut a large hole in the base of the drill and to place it over a tall table with a corresponding hole doesn't seem to me a great idea, so I'm thinking to another solution.

My drill is on a high standalone cart, with the back rounded to have the chuck always hanging out of the table if I turn the head around the column (I made that years ago: sometimes I'm prescient).

I'm planning to place on the drill column a couple of pipe clamps, those with an M8 screw to be inserted into a wall plug - the Italian version here: http://www.fischeritalia.it/static/prodotti/fissaggi_idrotermosanitari/CGITS_CPT.pdf - screwing a threaded rod into them.

The aluminum bar will be held outside the table between two plates, acting like the jaws of a vise, moving along the threaded rods and locked with nuts. Maybe the image gives a better idea of this jig.



To keep the head of the bar in the right position, then, all I have to do is to move the jaws along the threaded rods until the bar is true with the drill bit.

Since these clamps don't give a great vertical support, I'll place some bricks and a machinist jack on the floor, and a bag of cement on the drill base to act as a counterweight. I'll take some photos when I'll make this job.

I think this jig (or is it a fixture?) could be useful even for who has a high drill, because long parts can't be precisely held, if the vise is too far: think to something like a lathe steady rest running up and down along the column. Here is my idea of it.



If the piece you have to drill is really tall, you can hang your drill out of a 2nd or 3rd floor window (but in this case don't forget a heavy counterweight!!!).

Do you think there is a better way to do this?

Marco

 

[melsdad]

To be completely honest that set-up has no rigidity. Yes, your bricks and machinist jack will absorb the drilling forces, but the threaded rods will move around like noodles.

Maybe you can clamp a v-block to your table and rotate it on the column to the side with enough clearance to center your bar under the spindle. Then the part can be clamped to the v-block. And use your jack system under the bar as you stated.

 

[Barnesrickw]

Make a long bushing that holds the bar by clamping down on it. Slot the section of the bushing for the aluminum rod and use a hose clamp. Other half of the jig holds the drill bit at 90 degrees like a doweling jig. Do them on your bench with a large hand drill.


Sent from my iPad using Tapatalk

 

[jamie76x]

Before I had large machinery that could handle these jobs I used to do this ...

My press had a table that rotated or would slide straight up out of bore in the arm. It has a split and clamp to tighten and loosen. I would take the table out and make a bushing for what ever size stock I needed to drill. It holds it the right distance from the column, you just have to get the left and right set perfect.

 

[pineyfolks]

What size and how deep is the hole? Maybe you could make a cap with a drill bushing or guide and just use a hand drill.

 

[toag]

do you have a lathe? if you do you can put the bit in the 3 jaw, remove the crosslide and make a table to hold the bars

 

[Marco Bernardini]

Thanks everybody for the kind suggestions!

@melsad:

Your idea of using the drill table sounds promising.
Maybe I can enlarge the center hole to 30 mm, so my square 20×20mm bar will fit into it, and I can lock it to the table (of course with the jack on the floor) even with the usual vise.

@Barnesrickw & @pineyfolks:

The idea of the hand drill (I hope a hand power drill, not a breast drill!) get a honorable second place, in case I can't use the press drill.
I have to make 7 holes Ø 5 mm, depth 35 mm, tapped for an M6 screw.

@jamie76x:

Your drill press seems interesting! Can you find images of it, please?

@toag:

Sorry, no lathe!
And 7 holes for a small aluminum gate are not enough to persuade wifey I absolutely need a lathe…

 

[toag]

This sounds exactly like why you need a lathe. As much as i'd like to disagree with your wife... it is hard to argue with "NO"

Why are women always right?

let us know how it turns out!

 

[jamie76x]

Does your drill press table have a hole thru it? You can also clamp your bar stock in a V block then clamp the V block to the table to keep it square​

 

[Marco Bernardini]

Re: Jig to drill a 40" bar with a 13" bench drill press

This sounds exactly like why you need a lathe. As much as i'd like to disagree with your wife... it is hard to argue with "NO"

Why are women always right?

let us know how it turns out!

Uhm…

maybe I can ask wifey to enlarge the hole in the table (Chinese cast iron) with some sand paper: a good way to have a lathe for Monday morning :lmao:

- - - Updated - - -

Does your drill press table have a hole thru it? You can also clamp your bar stock in a V block then clamp the V block to the table to keep it square​

The drill is exactly like the Grizzly one, color apart:
http://www.grizzly.com/products/G7942
(even if he is persuaded to be a Bridgeport knee mill).
The bar is square, so there is not even the need of a V block: a couple of pieces of L iron bars will keep it in place.