Hello Everyone. I need help from the experts regarding drilling out a hole for the top of my gas pump. This will allow a light bulb to protrude through the top and into my globe. Unfortunately, I realized this after I painted the top sheet metal piece. The hole needs to be made where the 4 smaller holes are located in the picture. I was thinking of using a 2 inch bi-metal hole saw(picture ) to complete the task. Is this a good plan of attack? If so, should I drill from the back or top? Should I tape the area before I drill? Should I use reverse or forward direction on the drill?

Thanks
Marvin

I would tape the whole area first, drill a pilot hole and go for it but I am by far no expert!

The way I see it, the two issues you will have are the bit jumping and scratching and getting the metal too hot as to blister the paint.

Since a globe holder is going on top, it doesn't have to be a super clean cut.

Your hole saw uses a pilot hole so you shouldn't have an issue with it jumping around, just take you time making the pilot hole, even make one prior to using the one in the hole saw.

Take you time with the 2" hole, but it should go through easily. If not, stop and cool the metal down about halfway through.

I would begin by drilling a smaller pilot hole in the centre so that the pilot bit on the hole saw does not jump on you. Then I would slowly drill from the top until you have "scored" the metal to approx. 1/2 the thickness of the metal. Then complete the hole from the underside. Forward direction on the drill, but not full out speed. Cutting fluid will also help.

My opinion, I am by no means an expert on the subject.

It's best to use a drill press when using a hole saw w/o pilot bit, but can be done w/ a pilot bit in hole saw & electric hand drill. IF you have to use a hand drill, I would place top on a piece of wood [2x4,2x6]on floor & use feet to hold top, both hands on hand drill.
Tape off the complete top w/ a couple layers or use a thick poster board, hot chips will ruin the paint.

You can do this both ways, drill press (better) or a hand drill (if you don't have access to a drill press). The hand held drill must be a variable speed drill.

Mask the entire top to protect the finish from hot metal flakes and a run away drill bit. I would drill a 1/8" hole first, most pilot bits for a hole saw are 1/4". You want to keep the speed low and the feed rate low. These are the variables that will create heat and cause distortion of the metal.

Drill it slowly and take your time. Not a race to the finish line. You'll have no problems. Remember light steady, controlled pressure; you want the hole saw to do the cutting and not your body weight. You want have to worry about the top moving around if you have light pressure.

start off with a spring loaded punch & there won't be no run away drill..

Spray bottle with water to keep it cool?And be careful you don't catch the teeth on those already drilled holes.

Everyone is giving good advice.
Just an additional thought..
I was going to tackle a similar situation,when my neighbor told me my local High schools' shop class was looking for things to do.
The industrial arts section of many schools has dried up considerably over the past 15/20 years in some areas...They are coming back,but at a snails pace.
I contacted the shop teacher,who was more then happy to do what I wanted done,and for free,as long as I didn't need it back in a hurry or want a perfect job,as my project was indeed a learning & practice & experience for kids.
I agreed and was very happy to help.I got the work back fine,although it took a long time,but I wasn't in a hurry.
This might not be a desirable option to you,because you have a pristinely painted item,but just a thought.

Std drills only cut when running forward.

Yes mask everything

Yes use a light oil or cutting fluid

Yes use very light pressure and let the tool do the work

i would just use a shotgun to make the hole !

Thanks to all who replied. I'll be getting started on this part of my project later this afternoon.

Marvin

Make sure to let us know; How you made out.

If it's not too late. Tape off the painted front and cut the hole from the back with a metal blade in a scroll saw. I do it all the time and it works nicely. Paul www.severngaspumps.com

Dick, Id like to have a video of you trying to drill that hole without a pilot bit.