Upside down DIY drill press for working under the RV

[profdant139]

I’m getting ready to enclose the underbelly on my trailer – a job that involves drilling some small holes in the underside of the chassis. Is there anything more fun than drilling into metal upside down in tight quarters? Yes. Lots of things are more fun than that.

So, after a little Googling, I came up with an Upside Down DIY Drill Press. The goal was to hold the drill bit steady against the metal and to put just the right amount of pressure on the bit, as it cuts slowly into the metal.

The key is the jack underneath the drill motor – an idea I copied from someone else. I then took my corded drill motor and mounted it upside down on a small piece of plywood. Two 6 inch lag bolts are on either side of the motor housing, and a steel hose clamp squeezes the lag bolts against the sides of the drill. The whole thing is then clamped to the top of the jack.

I put another small steel hose clamp on the trigger, so that I could very precisely control the speed of the drill – slow is good when going into metal. I like it when the drill spins off spiral cuttings, rather than little sharp metal flakes – much easier to clean up!

I hope other folks who find themselves on the dark side of the RV can make use of this trick (and maybe improve on it). Here is a one-minute video:

Upside down DIY drill press for working under the RV

And here is a photo:


Click For Full-Size Image.

[profdant139]

afidel, that is a good tip about the impact driver -- I will have to try that!

[afidel]

Yeah, my BAL Lock Arms came with self tapping screws, using a 12V impact driver they went in easier than 2" screws in wood.

[profdant139]

out for a rip, this is for an aluminum frame to enclose the underbelly. A big project, a long way from done.

And 2DHoop, it is very easy to move the assembly around -- the whole thing slides on the concrete driveway, no problem.

[2DHoop]

I would think that the resetting process for each hole would be too time consuming and extinguish the delightment of the ingenuity in a hurry...unless you are on a flat, smooth surface and can build a platform on wheels to roll the drill from location-to-location.

A good quality self-tapping screw (not Phillips head) would be my initial choice, as others have mentioned.

[out_for_a_rip]

Interesting idea.

X2 on the mag drill, very fast set up but most don't have access to one.

What material are you attaching?

[profdant139]

rh, I discovered that it was hard to "tune" the triggers on my cordless drills to a very slow speed for this drill press project. The corded trigger works much better for that purpose. For most of what I do, I use cordless, though.

[rhagfo]

One other thing, time to get a cordless drill. No fighting with cords, have them getting hung up.

[Lantley]

Self tapping screws will go in with ease. Being able to lay on your back and push up is also a plus. No drill press required. I think you will be surprised how well the screws work.

[rhagfo]

Cummins12V98 wrote:
They make self drilling screws for many metal thicknesses. These with flat washers work well.

profdant139 wrote:
Cummins, will a self drilling screw just cut right through the wall of a steel frame member under a travel trailer? That's amazing -- the cutting head must be made of heat-treated steel.

I'm assuming you still have to put a lot of upward pressure on the screw and the drill has to be going very slowly, right?

I just bought self drilling hex headed screws at HD when I inclosed the belly of our 5th wheel, no trouble at all.

[MustangDan74]

Slow with a small diameter drill is not better. You need RPM and feed. You want chips, not stringers. Cutting oil is key, your drills will last much longer using proper feed and speed (as mentioned earlier).

[Cummins12V98]

profdant139 wrote:
Cummins, will a self drilling screw just cut right through the wall of a steel frame member under a travel trailer? That's amazing -- the cutting head must be made of heat-treated steel.

I'm assuming you still have to put a lot of upward pressure on the screw and the drill has to be going very slowly, right?

Steady pressure at a moderate speed they cut like butter!!!

[TNGW1500SE]

Good idea. All you need now is to hook it up to WiFi and have Alexa turn it on and off.

[westend]

Isn't it, "necessity is the mother of invention"?
FWIW, there are magnetic drill press bases available (if you plan on opening a factory, lol). Also, when I used to fab SS, we used variacs to control the motor speed. That, and the hardest Nitride bit know to man.

[Lynnmor]

There are self drilling screws used in many places on most RVs, and yes, they are hardened.

There is a correct speed to run a drill, slower is not better, correct is best. Google speed and feed charts for more information.