80mm hole to 90mm in 1/4" steel

[Ford850]

I used a Milwaukee Hole Dozer (non carbide model) hole saw to drill 4 1/4" (108mm) in a couple 1/4" steel plates. I used a little bench top drill press and only had wd40 for lube. It worked much easier than expected, only taking a couple minutes. The saw still looks like new, with the only some pain rubbed off on the welded seam. I think I could probably use a hand drill if that's all I had. A mag drill would also work if you can rent one.

 

[TractorGuy]

Found a carbide cutter 90mm hole saw on Amazon. You could use it to cut a hole in some wood, plastic, or metal to make a guide. Clamp or weld the guide over the 80mm hole and have at it.

 

[fitterski]

Jeeez, I forgot to check in after the first reminder and did't suspect a ton of great advice already waiting. My apologies! Happens al he time, I wish I could get an alert on each reply.

I've done the tacked strip for a pilot hole before, also done the guide-bore holding hole made of plywood. The double hole-saw is news to me, never done that but it sure sounds like a good one too.

What worries me is the 1/4" (vertical) steel that I cannot put into a drill press. I'm scared that it's gonna take a day and who knows how many holesaws.

Also there is a new tag in the mix. The purpose of the holes is to fit the round lip of flange bearings into the side of a snowblower, 2 augers, hence 4 holes.



But since posting someone has suggested that the round lip is for alignment and not for housing support. My alignment can afford to be rough, like 1/8-1/4". The support is allegedly more than handled by four 1/2" bolts holding each housing to the blower body, so all I would need is a 1/4" thick washer to put around the lip with holes to pass the bolts through. This I could make out of polyethelene in minutes. I'd like to have this advice seconded though, the bearings cost 60 a piece and that alone is reason for prudence

 

[fitterski]

Just in passing I finally managed to drill with a hole cutter in 1/4" aluminum in a drill press (unrelated job). I definitely would not want to try that in a 1/4" piece of steel that I can't even lay horizontal.

 

[Ford850]

Just in passing I finally managed to drill with a hole cutter in 1/4" aluminum in a drill press (unrelated job). I definitely would not want to try that in a 1/4" piece of steel that I can't even lay horizontal.

I'd rather cut steel than aluminum. I cut a 5" (127mm) hole with a hole saw in 1/4" aluminum a couple weeks ago, using a small drill press. That was a rough job, and much worse than cutting steel using the same setup. I got through it, but I wouldn't want to do that very often.

 

[fitterski]

I'd rather cut steel than aluminum. I cut a 5" (127mm) hole with a hole saw in 1/4" aluminum a couple weeks ago, using a small drill press. That was a rough job, and much worse than cutting steel using the same setup. I got through it, but I wouldn't want to do that very often.

I'll have to give this a try sometime. Maybe I'll start with a confidence building drill-press exercise using steel, the OP issue has been settled though, I worked around it.

 

[radios1]

I'll have to give this a try sometime. Maybe I'll start with a confidence building drill-press exercise using steel, the OP issue has been settled though, I worked around it.

if you use a 5" hole saw for steel, use 65 RPM. too fast will cause problems. Hole saw RPMs so you cut the perfect hole as for Aluminum, a lubricant should be used to prevent the Aluminum from welding to the blade..