we had new hardwoods installed in a room that has a fireplace.  The fireplace has a gas line that runs under the floor with a valve that can open or close with a key.  There should be a 1 1/4 hole in the wood floor above the valve in the gas line allowing access to open or close the valve.  The hole above the valve is too small and won't allow access to the valve.

 

I would like to enlarge the hole so I looked for a non arbored hole saw to cut a larger hole, but I can't seem to find one that is made for wood.  I can't use a hole saw with an arbor or spade bit because it would hit the valve on the gas line before completing the cut in the floor.

 

Are there hole saws without an arbor or is there a different tool I could use ?  Last resort would be taking a 1/8 drill bit and going around in a circle and then trying to file the circle smooth. 

Edited November 20, 20178 yr by Ron Dudelston
tags added

If you have a router, you could make a round template and attach it to the floor with double sided sticky tape. Then using a straight cutting bit create a larger hole. Depending on the bits available ( top bearing), the template may only need a round hole the diameter of the new hole you wish to create

Most hole saws that have interchangeable mandrels also have a removable pilot bit. Remove the pilot bit but leave the mandrel attached to the hole saw.

Mark your hole OD with a pencil or felt tip centered around the current opening...you could make a template by first drilling through a scrap piece of wood and laying over the hole as a guide too

Use a variable speed (preferably corded in this case) drill at low/slow speed with moderate down pressure to open up hole diameter.

I assume you're only talking about a 3/4" or less floor thickness??? Even so, these styles will drill to ~1-1/2" depth.

 

Example of interchangeable mandrel (arbor) for various size hole saws with removable/replaceable pilot bit

Edit add: BTW...Welcome Carey to TPW. Glad you found us and jumped right in with a question. I believe you'll find this a great place to hang your hat and call home. Take a look around and if you have any questions about the site, don't hesitate to ask. We try to be a friendly group and enjoy sharing and learning together.

Edited December 19, 20169 yr by Grandpadave52

The hole saws pictured in Dave's post can be purchased individually at HD. Nice to have the set, but they are somewhat pricey.

Welcome to the forums Carey

 

Edited December 19, 20169 yr by It Was Al B

enlarge the hole w/ one holesaw inside of the other...

http://www.lenoxtools.com/pages/lenox-wood-metal-cutting-bi-metal-hole-saws.aspx

http://www.leevalley.com/US/wood/page.aspx?p=52518&cat=1,180,42316

 

5 hours ago, Stick486 said:

enlarge the hole w/ one holesaw inside of the other...

Forgot about this idea!

7 hours ago, Stick486 said:

enlarge the hole w/ one holesaw inside of the other...

http://www.lenoxtools.com/pages/lenox-wood-metal-cutting-bi-metal-hole-saws.aspx

http://www.leevalley.com/US/wood/page.aspx?p=52518&cat=1,180,42316

 

One whale of a good idea!

Thanks for all the suggestions.  I will look into the pattern bit for a router and the kit for the hole saws - I didn't realize you could remove the pilot bit.

You could also drill a piece of scrap wood with the proper sized hole saw with the pilot bit, remove the pilot bit, attach the scrap board to floor with double faced tape, center over existing hole and drill.  The hole in the scrap will keep it centered.  

 Sticks method is the best but you need the exact size hole saw for the existing hole.       Roly

5 hours ago, Roly said:

You could also drill a piece of scrap wood with the proper sized hole saw with the pilot bit, remove the pilot bit, attach the scrap board to floor with double faced tape, center over existing hole and drill.  The hole in the scrap will keep it centered.  

 Sticks method is the best but you need the exact size hole saw for the existing hole.       Roly

Roly's right, This is how I do it, it is hard for me to start a hole saw with out a pilot bit,so I use the scrap as the pilot. I like Sticks method too it would be a great way to enlarge a hole that was drilled too small.