How big a hole do I need?

   / How big a hole do I need? #1  

pat32rf

Veteran Member
Joined
Jul 21, 2004
Messages
1,986
Location
Bancroft, Ontario
Tractor
JD4300
I finally got fed up with repairing/replacing the lights on my little ATV trailer and am switching to the sealed units that they use in the bigger 18wheeler trailers. These fit into a rubber grommet that goes into a round hole. But how big is the round hole? My BIL had used them on a custom bumper on his truck but the shop doing the work cut his holes too big and now his lights fall out every now and then. The grommet stretches and distorts when it is over the light so I don't trust the measurement I get that way. Does anyone know the correct size hole to cut in my fender? I'd sooner just cut it once... :)
 
   / How big a hole do I need? #2  
I would think there should be some paperwork with the light that would have that information. What kind of light is it? Look up the manufacturers website, they will probably be able to help. Or, measure your BIL's, and start yours smaller, see if you like the fit, if not, then adjust. Keep adjusting till your happy.
 
   / How big a hole do I need? #3  
pat32rf said:
I finally got fed up with repairing/replacing the lights on my little ATV trailer and am switching to the sealed units that they use in the bigger 18wheeler trailers. These fit into a rubber grommet that goes into a round hole. But how big is the round hole? My BIL had used them on a custom bumper on his truck but the shop doing the work cut his holes too big and now his lights fall out every now and then. The grommet stretches and distorts when it is over the light so I don't trust the measurement I get that way. Does anyone know the correct size hole to cut in my fender? I'd sooner just cut it once... :)

Been there done that. I'm assuming you have a set of hole saws.....just take a thin piece of scrap metal, or some thin plywood or masonite and try a couple test holes, then see which ones fit your lights the best.

You can't start small and go bigger. A hole saw needs the middle left intact so the pilot drill has something to drill into.
 
   / How big a hole do I need? #5  
Builder said:
You can't start small and go bigger. A hole saw needs the middle left intact so the pilot drill has something to drill into.

Actually, there is a hole saw arbor that lets you stack two hole saws so you can cut a larger hole. I have one of these and use it quite a bit. You can see it here.
 
   / How big a hole do I need? #7  
If they are not the LED ones you will be worse off than before. I got those things on one of my horse trailers and just hate them. You can not relace the bulbs individually so if the running light or brake light goes out you got to replace the whole thing at about $8 a pop.
 
   / How big a hole do I need? #9  
Builder said:
But I still think it's more wise to know the hole size by drilling into scrap before drilling your expensive sheetmetal fenders, don't you?

I agree that it's better to cut the hole once. My point was that there is a device to help fix mistakes or to enlarge an existing hole. I work on boats and I'm pulling out old thruhulls to put in larger ones and use that little arbor quite a bit. Works like a charm.
 
   / How big a hole do I need? #10  
Shimon said:
I agree that it's better to cut the hole once. My point was that there is a device to help fix mistakes or to enlarge an existing hole. I work on boats and I'm pulling out old thruhulls to put in larger ones and use that little arbor quite a bit. Works like a charm.

Oh, I hope you didn't take me the wrong way. That double hole saw is cool. I might get one.
 
 
Top