Adding new extension wings to my table saw and I need to drill...help!

Are you going to try drilling into the rails or the cast iron?

Either one can be accomplished with a cordless drill and a good metal bit.

Use a punch or something to give you an accurate centering spot.

-- Kevin, Wichita, Kansas

We drilling metal, start with a small bit (1/8”) and work your way up to the finished size. If you are going to have to thread the hole make sure you look up the proper drill size to the thread tap you are going to use. When drilling into the table you probably don’t need any lubricant. When threading the holes use a little oil. I use WD40 or motor oil or whatever I have on hand.

-- DaveH - Boise, Idaho - “How hard can it be? It's only wood!”

Cast iron is pretty soft and you can drill holes into it pretty easy, so no worries there. Just make sure you are not hitting a web on the back of the extension lip. Also, I would suggest is getting a inexpensive “transfer punch set” so you can mark the holes accurately. I was surprised how often I use my set and I think I paid less than $15 for them.
If you drill the cast iron you will not have to lubricate the drill bit. Like I said, the stuff is pretty soft but if you have a variable speed drill, go slow. If you don’t own a set of drill bits, now might be the time to buy a set of quality bits. But, otherwise figure out what size hole you need and just buy the ones you need. But I’d recommend getting a good quality drill bit because you will probably use them again in your lifetime.
I’d also recommend to drill the hole in your extension just a little bigger than the bolts that you are going to use to mount the tables with. This way you will have a little ‘fudge’ factor for adjustment.

-- Jim

What kind of fence system do you have on your saw? I have a 90’s Delta contractor saw with the Unifence and there are no holes drilled in the wings, only two in the main top. If holes are need in the wings, take the fence rail off and measure from center to center along all of the holes and then lay it out on the saw, with the wings installed. Like everyone else has said, the cast iron is soft and will drill easier than steel. Don’t predrill with too small a drill bit if you’re using a cordless drill, because they won’t turn fast enough and you’ll end up breaking the bit.

I agree with the some of the other posts. I believe you will find it easier to drill than you think. It is soft stuff. Just drill a little large for adjustment.

-- -- I'm no rocket surgeon

Thanks everyone. I am glad I asked. I was just assuming I would need to drill the steel rails, but I belive it would be much easier to drill the cast iron and match the hole to the already existing ones in the rails. I have a good set of Dewalt twist drills that should work. I look into a transfer punch set. Thanks again everybody!

-- The Hand Tool School is Open for Business! Check out my blog and podcast "The Renaissance Woodworker" at www.renaissancewoodworker.com

A few weekends have gone by and I have been out of town, but I took the time to get a transfer punch set at a good price on ebay. So I am back in the shop to finally get these wings put in place. I have positioned them and attached the bolts that tie them directly to the saw top. Now I see that the holes in my fence rails perfectly align with the undercarriage cross piece of the wing. You cannot see it but the existing hole in the rail is perfectly centered across the width of the wing, smack behind that cross support.

So since I got such a helpful response last time, I figured I could get some good advice again. What next, Can I still drill into the cast iron or will that weaken the wing since I will be removing the support pieces? Will it be easier to just drill the steel rail? You can see that there are already two holes in the wing.

Thanks again for the help.

-- The Hand Tool School is Open for Business! Check out my blog and podcast "The Renaissance Woodworker" at www.renaissancewoodworker.com

Cast iron is a lot more brittle than steel. I would drill the steel.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

I agree with Gary, drill the steel. Because the wing is already supported by the bolts in the table top, I would only drill a hole at the outer location (right side in your picture) on each end of the wing. That should provide enough support for most applications.

If you haven’t already considered it, this is an excellent location for a router table. Especially if you have a very small shop.

Lew

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

If I had a setup like you have with the two holes in the wing and with the hole in the angle iron lined up behind a web I’d drill the angle iron also. It will be a little tougher going, but take your time and use a sharp bit.
Make sure that you drill a smaller hole in the angle iron that what is in your wing because you will need to have a little ‘wiggle room’ for adjusting the wing and use washers on the cast iron side.

-- Jim