Need tips on making holes bigger!

[Pat Barry]

I have a need to enlarge some holes to a larger diameter and I need to do it accurately. The holes are 3/4" dia in Ash and are approx 2 1/4" deep. OK - I'll admit it - I messed up drilling some of my dog holes - they drifted off from the intended centerline. Not sure if it was because of operator error or the bit design itself - used a spade bit. Anyway, what I'd like to do is drill them out, oversize, but accurately this time so that I can insert a plug and then drill new accurate dog holes in the plugs. I'm thinking to go with 1 1/4 or 1 1/2" holes to fix the error and then insert close fitting plugs (probably from Oak or Ash or Maple dowel rod). I don't want to use the spade bit this time - will probably go with a Forstner bit for the finished 3/4" hole. Any thoughts appreciated!

[dave toney]

Can you drill them out with a drill press?
Use a forstner bit, they guide from the edge.
Tack a piece of thin scrap over the hole to mark a new center.

[Anthony Whitesell]

Here's on option I have used to enlarge holes.

1- Clamp a piece of scrap behind the hole and re-insert the drill bit to mark the center of the hole
2- Use a 1/4" drill bit to drill the center of the scrap
3- Using a hole saw bit of the correct size, replace the drill bit with a 1/4" metal rod and enlarge away

But I also have to ask, if the sides of the holes are smooth and straight, why not just plug them as is with a piece of 3/4" dowel?

I had a similar problem when making my bench, the template was not perfect and the incremental error was huge after drilling 5' of 6" apart holes. The holes were smooth so I glued 3/4" poplar plugs in place and re-drilled with a template that wasn't based on the previous hole location. My choice was poplar or red oak for cheap wooden dowels and didn't know how at the time to make my own (4 passes with a roundover bit on the router table)

[Pat Barry]

Anthony - biggest problem is the holes are not straight thru - they are slanted a bit and unfortunately for me its the wrong direction. If they were tipped toward my vice it probably wouldn't hurt a bit.

[Pat Barry]

Dave - I like the Forstner bit idea. I have a bench top drill press. Mayb e I can stick it in position on my workbench and drill the holes. I will check on whether this will work. Otherwise it will be difficult to support a big heavy benchtop on the drill press itself. Good thought though. I'll let you know if it can work.

[Forrest Bonner]

I, too, have mis-drilled holes. My response was to use the correct size Forstner bit and drill a pilot hole with it thru a piece of scrap - use the drill press for this to assure a straight hole. Locate that hole over your workpiece where you want the 'final' hole to be. Tack the scrap in that position and use the scrap hole as a guide to keep the Forstner bit from roaming. Make the scrap as thick as you can to provide as long a support for the bit. Once you are in the real wood your bit should track true. This works well if you have to hand-drill and will help keep the hole straight. If you want an angled hole, drill the hole in the scrap at the angle desired but make that scrap thick. Drill press would be you best bet if you can. I agree that you do not want to use a spade bit.
Forrest

[Matt Day]

I like Anthony's suggestion abou the hole saw as well as simply using a forstner bit - but either way you need a drill press and make sure the wood is clamped down securely or the bit will not stay true. An in either case, if the bit isn't supported by the wood it's cutting properly (i.e. it's cutting a sliver of wood on one side, and 1/2" on the other) it will want to wander so watch out for that.

[Anthony Whitesell]

They are not straight or they are not vertical?

Even if the holes are one or neither, my original proposal will still work, just don't worry about finding the center, pick something convenient and drill out using an oversized holesaw and then plug and redrill with the correct bit. Being that the holesaw is probably only 1 to 1 1/2" deep, you'll have to stop and break out the edges of the first part of the hole before you can finish drilling all the way through.

If they are straight sided but not vertical then plug the holes, cut the dowel long flush trim and sand smooth.

[Jay Maiers]

I'd use a router and a template.

[David Larsen]

I'd use a router and a template.

2 1/4 inches deep and at an angle? I would have to disagree!

[glenn bradley]

I'd use a router and a template.

I've used spade, Forstner and a 3/4" bradpoint bit for dog holes. Best result was with a router; perfect every time. As to the hole repair. I have just used generous amounts of glue and glued in 3/4" oak dowels, then use the router in the intended spot. You may remove nearly all of the "plug" but, this has not been an issue.

[lowell holmes]

I would consider plugging the holes and cutting them flush. Then I would redrill the holes on un-disturbed wood.

[Jay Maiers]

2 1/4 inches deep and at an angle? I would have to disagree!

Baby steps. Start by using the drill press, forstner bit, and a fence to produce a full-length template of the hole pattern you want in the bench. Clamp the template to the bench. Use the router and a large collar to enlarge the existing hole by 1/4" total. You could do this in two, three, or more passes, each at a different depth. Wash, rinse, and repeat with different collars until the desired hole size is achieved. Plug. Use the template again to make new holes.

All of this assumes that you can lay out the template properly and have the collars, bits, and a router capable of doing the job right. IMO, if the OP drilled the holes off center and off camber the first time, there's at least a decent chance of it happening again. (OP: No offense intended :) I'm quite sure I would have those holes pointing every which way and wandering at the same time!) This process also assumes that the old hole pattern is close enough to the new pattern for the two to overlap.


Why do the holes need to be at an angle? I've heard that some folks do it that way, but I've also heard from many people that bore them straight. Do they really need to be at an angle?

ETA: If I needed to drill the holes instead of using the router, I'd probably take my benchtop drill press, chop the column and use it in place of a hand drill. I know for a fact that I am not capable of drilling that many consistant holes in a row.

[Larry Edgerton]

I, too, have mis-drilled holes. My response was to use the correct size Forstner bit and drill a pilot hole with it thru a piece of scrap - use the drill press for this to assure a straight hole. Locate that hole over your workpiece where you want the 'final' hole to be. Tack the scrap in that position and use the scrap hole as a guide to keep the Forstner bit from roaming. Make the scrap as thick as you can to provide as long a support for the bit. Once you are in the real wood your bit should track true. This works well if you have to hand-drill and will help keep the hole straight. If you want an angled hole, drill the hole in the scrap at the angle desired but make that scrap thick. Drill press would be you best bet if you can. I agree that you do not want to use a spade bit.
Forrest

I use this method often on site when I do not or can not use a drill press, works well.

Oh, throw those spade bits away!

Larry

Oh ya, if you want to just step up a size or two you can use a sheetmetal step bit to start the hole for the next size forstner bit, handy sometimes..........

[Nathan Callender]

I have to agree with Larry and Forrest on this one - that is what I would do. There's probably no way to jig the drill press up without a lot of effort, and you should be able to get reasonably good results with this method. One minor addition would be to add a piece of scrap under the template as a fence to put against the workbench so all your holes are now the same distance from the edge.

I also agree that spade bits do not belong in a wood shop. They are best used to put crude holes through soft studs - anything else requires a design with a little more precision.

[Pat Barry]

Guys - thanks for all the feedback so far. Note - the holes were supposed to be straight (vertical). They came out angled and now I want to get them right. I'm thinking the Forstner bit and guide idea makes the most sense for the tools I have to work with. Saturday I'll get a chance to work on this. Biggest concern I have is I don't want to compound my problems. This time I will practice on scrap before doing the real thing.

[Neil Brooks]

I also agree that spade bits do not belong in a wood shop. They are best used to put crude holes through soft studs - anything else requires a design with a little more precision.

Agreed.

Count me in, by the way.

It was way too late, when I was just about finished with my bench, and the next step was drilling the dog holes.

[everybody know this story, already ?]

What the heck. I'll start the holes with my guide jig and a Forstner, and then finish them off with a spade bit. I had bought a 12" long 3/4" Bosch auger bit, but it wouldn't chuck up in either of my drills.

So ... using the spirit level on the back of my drill as my guide ... I took my time and drilled them all out.

Maybe half were good. The other half ... like Pat's ... range from ever-so-slightly off to a fair bit off.

Really, really .... they work FINE, and I never re-did them. The bench dogs -- when you stick a spirit level on top of them -- DO show which way I screwed up, but .... it has never caused a working problem.

https://lh5.googleusercontent.com/_WVVYjLCNo2w/TSzmWNnsoMI/AAAAAAAAB-4/1Wtsh6cLGnI/s640/P1050089.JPG

But I DID by a right-angle drill guide, for when I finally get around to putting the dog holes on my vise faces.

I'm guessing most of us have one of those "I knew I should have stopped working, but ....." stories.

That's mine :o

And ... as long as they don't end up with ER trips ... it's just wood, time, and aggravation :)

[ray hampton]

you stated that you got a bench top drill press, can you drill the hole at one setting [quill travel ] unless you can buy forstner bits with a longer shaft I will recommended a twist drill long enough for drilling the hole without extra steps

[Brian Foree]

Not knowing how your bench is constructed, but if it doesn't have bread board ends and is only 2 1/4" deep, I would think about just ripping off the messed up part with a circular saw, bandsaw or table saw. You could then glue a new piece on or use your router and have square/rectangular dog holes. Drilling and plugging then drilling again only to have a hacked up bench doesn't sound like the optimal route... at least not to me.

[Pat Barry]

Hey Neil, my drill had the spirit level also. LOL. I thought I held it pretty stable while I drilled too.

[Pat Barry]

Brian - that's not going to happen.

[Erik France]

I did my dog holes with a 3/4" spiral in my plunge router and finished off the hole with a forstner in a drill. I found a fairly inexpensive upcut HSS 3/4" spiral at woodcraft, but I don't think they carry them anymore. MLCS has them for $15. My holes were straight & perpendicular. Using an edge guide and a spacer block made them very consistent.

[keith ouellette]

Plunge router. Thats the only way I can think of to corrct the problem. I don't know if anyone mentioned this but a forstner bit will will move all over the place if the centering spike isn't in wood.

A plunge router will solve the problem. Even if you use a combo of plunge router to re size the whole and then finish with forstner bit for depth.

[Jim Matthews]

I can't see why the slope or position of the dog holes matter.

I use the Veritas benchblades and they fit into sloppy, off-center holes just fine.
Given that they can be ginched in tight (slip wedge fixture, like old-school bicycle handlebar stems) and are only about 1.75" deep - misalignment is not a big deal.

They have a cam locking mechanism which is VERY fault tolerant.
http://www.leevalley.com/us/wood/page.aspx?p=64685&cat=1,41637

Benches are tools, not jewelry boxes.189300

[Ruhi Arslan]

If it is about positioning the bit (whatever bit that might be) at a point that is already bored out, a square 3/4" peg jammed into the round hole would give you the support at the new center to start your new hole over the existing hole.

[Joe Angrisani]

Pat.... To back up a little: I would agree with your initial thoughts to bore the holes out oversize, then drill new dogholes that live completely within the repair. I wouldn't want a glue line right at the edge of the new holes or angling through the new holes at a slight angle. Could misguide your redrilling of the holes. Make the repair bigger than what you need to fix.

Use your drill press to put a hole in a piece of 2x4 with the 1-1/4" or 1-1/2" tool you mentioned. Clamp this over the existing hole to guide the 1-1/4"-1-1/2" tool into the bench in the manner suggested by Forrest. Then use Forrest's idea to make a strip with the 3/4" holes laid out precisely, and use it and a pair of combo squares on end to help you "see" that you stay perpendicular in both planes as you bore.

[Mike Konobeck]

Just got done drilling a ton of holes in 2 benches w/ 3.5" tops. Gotta say it wasn't the most fun part of building them. Hard maple is a pain. I read Chris's book and he said he drills the holes freehand so I decided to do the same. I don't think it really matters that much unless the holes are WAY off. If they are a little off then the piece is not going anywhere when clamped up.

That being said, if I was to do it over again I would likely take the time to setup the supports and use the drill press or come up with a better template system for drilling the holes straight and evenly spaced. The main problem that I had was the bit would heat up so much that I needed to use water to quench the bit a lot. That would be a pain in the press so a template/jig would likely win out in the end. I used the Colt Twinland (http://www.woodcraft.com/Product/2005566/16670/34-Fractional-Brad-Point-Bit.aspx) bit from Woodcraft. The hole is very clean and it is a fairly agressive bit but I had to use a serious Bosch hammer drill (not in hammer mode) to make the holes and had to stop frequently to let the drill cool down. Make sure no matter what you do you use a backer board so it doesn't blow out the exit side of the hole. I looked at the Colt MaxiCut (http://www.woodcraft.com/Product/2080329/28201/MaxiCut-Forstner-Bit-34.aspx) too as I think that it has a nice wide exit path for the chips which is important when the bit is plunged that deep. It was more expensive but I should have just spent the money and tried it because it might have saved me some time. The nice thing about the brad point bit is that there is no room to tip the drill once you have some of the bit sunk in the wood. Every other style of bit doesn't so you can actully make a curved hole.

Anyway, lots of info here so good luck fixing the holes if you decide to. I would suggest just using it though and determining what you can't live with in the long run before making more work for yourself.

[Ronald Blue]

I agree with Lowell. Plug them and re-drill. That's the easiest solution.

[Steve Orbine]

This is what I would do too. Plug the messed up holes (use glue), plane the tops flush and start over with a larger forstner bit. If you want to hide the screw up you could use a brass bushing in the new larger hole.

[Richard Rodgers]

Plunge router with a large bottoming bit and a shaft extension like used for bowls to get extra depth. The large bit will remove the angled area as it cuts the new straight hole. Just clamp the router base over the old hole and plunge in.