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Drill Sizes - LP Propane to Natural Gas Conversion Drilling Tips

Drilling out your Grill or Stove Propane Orifices  from LP to Natural Gas

Moving from Propane to Natural Gas is the ONLY direction that will allow you to do this because the hole for Natural Gas is Larger and technically can be drilled out. Do we recommend it to the average user? NO we do not .

What size hole should you have for your orifices?

There is very little information anywhere on what sizes orifices are for what grills –  All Sizes are in Drill numbers and in MM or Millimeters, the small the number of the drill, the Larger the hole.

A rule of thumb between LP and Natural Gas and are broken down into Tube burners and Cast Burners

LP or Liquid Propane Grills - 

LP Grills orifices that are 26″-32″ Tube burners and side burners uses – roughly #55 =1.33mm hole

LP Grills orifices that are 26″-32″ Cast burners  uses – roughly #56 = 1.2mm hole

Back burners average between #59 = 1.05mm or #60 = 1.0mm 

Look for a approximately 1 1/2" high flame for a good indicator for the height of the flame coming off the burner edge.


Natural Gas Grills -

Natural Gas Grill orifices that are 30″ Tube burner uses #42 = 2.35mm hole
Back burners average

Natural Gas Grill orifices that are 36″-42″ cast or brass burner  burner uses #42 or 2.35mm hole

Back burners average between #48mm = 1.93mm hole and #53 = 1.5mm  hole

Look for a approximately 1 1/2" high flame for a good indicator for the height of the flame comming off the burner edge.

Here are Words of wisdom from an experienced blogger 

Converting from LP to natural gas safely and correctly involves more than might be apparent to the typical DIYer.

Frankly, it’s folly to drill out orifices. If you can get the correct orifice, don’t do it.

You need to get the correct sized orifice, get the gas pressure correct which may involve a new regulator, adjust the primary air shutters correctly and generally be able to look at the equipment and how it’s operating to be sure it’s correct.

Not really a good DIY project, in my opinion. Too many things that require some judgment and experience to get correct.

Sources – Read more:

One more from a 15 Year veteran

You need to contact the manufacturer for a conversion kit. The most important thing in that conversion kit is a new rating plate for the appliance. This certifies that the manufacturer has “approved” the appliance for use with that fuel. 15 years ago we could just drill out orifices and away you go, but those days are long gone! The liability is too great.

If you “Mcgyver” the grill and convert it yourself, you better pray long and hard that no one gets hurt by that thing or it causes a fire! Insurance companies will deny any claims and the manufacturer will take no responsibility because you have “altered” the appliance.

Trust me! It’s not worth the risk! Either get an approved conversion kit or just replace the grill with a new natural gas model.

21 years experience in the propane business and a licenced gas fitter.

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