question on enlarging grommet hole

[westn11]

I have a grommet that measures roughly 1.65 inches that I would like to enlarge to 2.25. Besides plasma or grinder, does anyone have any tricks on how I can use a Hole Saw?

With the existing hole, I can't use the pilot drill on my HS... obviously :-)

 

[76zimmer]

a step bit?

 

[chevydan3]

Years ago, a guy on this site suggested this: Use the correct size hole saw on the arbor, there should still be some threads left on the arbor, screw another hole saw on the threads that is the size of the existing hole and use that as your guide.. Kinda like a hole saw inside of a hole saw

Sent from my BlackBerry 9810 using Tapatalk

 

[westn11]

I didn't realize they went that big? I just went and double checked, I need one to go 2 1/8. I'll check Home Depot tonight and see what they have.

Good idea on the hole saw inside of another one. Worth a shot.

Thanks for the help guys!

 

[Fordum]

Exactly 2.25??

A 2 inch conduit hole is 2-3/8. If you know any electricians, ask to borrow a 2 inch conduit Greenlee hole punch.
It makes a nice clean hole and you will only be 1/8 inch too big.
The draw stud is 3/4 inch, so it will not automatically line up. But you can eyeball it close enough unless the location is critical.

 

[westn11]

The stacked hole saw worked awesome!

Thanks for the replies. The stacked hole saw worked like a million bucks and I now have a new hole which works perfect with my larger grommet.

Thanks again.

 

[ryoken]

yup, it's a good way to do the FUSH install too... die grinder and a carbide burr work good too, usually quicker when ya include set up time...

 

[StuGutz]

Had to do a similar job on a buddies truck for a cage through the body. We came up with a small piece of plywood slightly larger than hole, and screwed it to the back side of the hole on the edges. made a center mark and drilled away. Hope this helps and hope you get what I mean

 

[diesel4me]

I did just that on a project I did not long ago............................................I used a peice of 3/4" plywood when I had to enlarge some rims center holes to 3-1/4" so they would fit my garden tractors hubs (they were 4.5" 5 lug ones off a Ford,my tractor uses that bolt pattern,but the center holes were too small)..I bolted the plywood to the lug holes with 3 bolts,and used a compass to find the center of the hole,and used the plywood as a back up,for the center hole for the drill bit to let the hole saw cut a accurate hole in the rim..did that when I put a CB antenna ball mount on my van where its fender already had a smaller hole than I needed too...couple of self tapping screws to hold the plywood behind the fender,it worked great....I'll have to remember the "double hole saw" trick too now!...

 

[ashman]

Thanks for the replies. The stacked hole saw worked like a million bucks and I now have a new hole which works perfect with my larger grommet.

Thanks again.

nice!! that is a trick I didn't know about. I'll be keeping that one in mind!

 

[chevydan3]

Gotta give Kert the credit.

http://coloradok5.com/forums/showthread.php?t=264007&highlight=double+hole