[tahoelfy]

Hey ,
What is the best drill bit to drill a 3" deep hole in the edge of 3/4 cdx and keep it from wandering? It is only3/16ths diameter. It is for these sawhorses.

I made a jig but the bit seems to wander into the next ply unexpectedly, maybe it is because of the glue.
thanks

 

[mako1]

I would find another sawhorse design although this one is cool..Why do you need to drill 3" into the edge of plywood? I looked at the link and see nowhere you would have to drill 3" into the edge of plywood.
If you are a custom furniture maker you would also know that a 3" screw into the edge of plywood will fail in a heartbeat.

 

[SectorSecurity]

Why does this seem to me like your the person running the kickstarter campaign and now that you have peoples money you have no idea how to deliver a finished product?

 

[mstrat]

Clearly Tahoe is new here, and doesn't know Basswood's horses have the CT market cornered. That being said, I'd get a 3/16" drill bit that's more than 3" long...maybe some of these 12" Cobalt 3/16" bits would do the trick?

 

[J.C.]

Dowl-It Jig and a good drill bit?

 

[hdavis]

I'm guessing it's for the 3/16" rod to go in.

The bad news is I don't think you'll be able to get that hole drilled straight enough for the rod to slip through. If you could spin the plywood and keep the bit stationary, you could use a self centering bit, but that's pretty much a non-starter.

 

[mako1]

I kinda thought a 3/16 rod but still.Drilling into end grain ply?How long will it take it to fail? First use?
My point was not how it could be done but why?

 

[JAH]

I watched the videos.
Dumb question for a furniture maker.
Nothing but a shameless advertisement.

 

[Tinstaafl]

Nothing but a shameless advertisement.

Based upon the same instinctive reaction, I've removed the link. Maybe he'll return to quell that suspicion.

 

[hdavis]

Since the saw horses are supposed to be delivered in November, he should be starting to build them now.

IMO, it works better if you figure out how you're going to actually make something as you design it. Yes, there's an answer to his dilemma, but the wrong question was asked.

Unsuscribed.

 

[tahoelfy]

Wow you guys are brutal. I asked simple question. I have been using a brad point bit but even that wants to wander. I was hoping maybe someone had some experience with a different grind, pointed, spoon bit, burn it. laser it, stiffer steel, pre drill.. I know how to build the horse they are not difficult , just a drill bit question. sorry to bother you. I will experiment some more . Those that did answer the question thanks. Those that made no attempt, bummer. tf

 

[tahoelfy]

Dowl-It Jig and a good drill bit?

Actually I like the dowel it jig idea. It is probably better than my jig. I may make one and try it. thanks

 

[hdavis]

OK, it's a simple question. OTOH, you don't say what tolerance you need. Any bit will wander, a spoon bit is probably the worst.

Personally, I would have designed this to use 3/16" ID pipe for the rod to slide into, and drilled for the pipe OD with room for epoxy. You get the precision you need built in, you spread the stress over a larger area, drilled hole size / straightness isn't critical any more, and wood shrinking and swelling isn't going to make a difference.

Or you could try drilling a 1/8" or 5/32" hole and use a pull through reamer to get it to 3/16". That would be custom made, but that's as good as you'll get going the drill route.

 

[jlsconstruction]

Could you take the table off of a drill press, and make a jig you can clamp your plywood in.

 

[tahoelfy]

thanks for thinking about it. Good solution if I had to make one, but multiples?? The rod throughout the ply is strong, I have tested. I just like it to be perfect. Maybe if could drill half from each way, hmm, let me think on that. Maybe I can get a right angle drill in there. Right now I use a channel with a long 12" plus bit, but is probably flexes enough to cause the wander. I should try a jobber bit just over 4" to account for a jig. tomorrow.

 

[tahoelfy]

The last time I tried I did it on the drill press with a vertical jig. Only ok results. Maybe with a better jig set up and shorter stiffer sharper bit. Don't worry I will get this , there must be a way. Just the 5 ply cdx has a center ply that is just 3/16 and the next ply and glue probably causes asymmetry on the bit . Wish I could drill a bigger hole but 1/4" takes out too much wood in my eye. oh well sleeping on it usually does it.

 

[hdavis]

1) Use a drill press, even a cheap bench drill press is better than a hand held with a guide, just mount it on the edge of the bench and swing the head over the side. Clamp you wok piece to the side of the bench.

2)Use the shortest drill bit that will work for you.

3) Use a split point drill (common for metal, haven't seen them for wood). You may have to have someone modify an existing bit for you, or buy a deluxe Drill Doctor and do it yourself.

If you want more info on precision hole drilling, read up on it in a machinist book.

I don't know of any cabinet maker who isn't familiar with drilling a larger hole and then sticking some metal in, it's a common, high precision, high strength, high volume, low cost technique, just ask IKEA.

 

[Railman]

Fab a wooden drill guide with a 3/16" ID hardened steel bushing insert. The guide would lap over the sides of the plywood, & insert would butt the plywood edge. The exposed side of guide could have an exact centerline for hole alignment. Then I'd go with an HS steel brad bit with wood style flutes ( fast slope, very open ). B&D bullet bits had this type of open flute, & might actually work for your use. Check out Fuller for an excellent variety of woodworking drill bits. They also sell bushings.

We typically just grind our own brad points for our shop use. If you take a normal hs steel bit, you can use the corner of a grinding wheel to remove just a little of the center of each cutting edge. It leaves a small point at the center, & a sharp edge at the outside, just like a brad point. The trick is to not grind too much. Sometimes I'll shape an acute/less than 90' corner in the grinding wheel to increase the brad point effect.

A centering dowel jig like this would be the easy fix:
http://www.rockler.com/self-centeri...erm=&utm_content=pla&utm_campaign=PL&sid=V9146&gclid=CNvL1PWB5sACFfA-MgodZAEAmw