HELP!!! BLO got in my dog holes and is sabotaging my hold fasts!

[chris carter]

A few days ago I re-flattened my work bench. I gave the newly exposed surface a coat of BLO. I didn't realize that when I first built the bench I applied BLO before I drilled the dog holes. So I think a tiny amount got into the lip of each hole. Today I tried to knock in a holdfast and they just would not hold AT ALL. Previously they held like a hungry lion locked onto a wounded giraffe - even with just hand pressure. Now, absolutely NO GRIP whatsoever - even whacking hard with a mallet. What do I do? Is this fixable? Did I just completely screw myself???

[Mark Gibney]

I'd get an old toothbrush, a small container of acetone, and scrub the walls of the dog holes.

When you've finished I'd get 100 grit sandpaper and rub the walls of the holes sideways a little.

[Don Dorn]

Interesting - just built a new bench and used 3/4" holes. I find them pretty tight and not nearly as easy to use as my old bench, especially in summer humidity. On the old one, I took the leap and reamed all the dog holes to 13/16". After that, I never had any problem getting anything in or out but wasn't "sloppy". I'm considering that again, but once you do it, you can't go backwards so I'm a bit hesitant. In the old bench, the BLO I put on once in a while was never an issue.

[Tom M King]

How about a round wire brush, found in the Plumbing section of box stores, for cleaning copper fittings to prepare for solder. If by hand is too slow, cut the handle off, and chuck it in a drill.

edited to add: Only spin it clockwise. If you go the opposite way that the bristles lay, or go back and forth with it, the bristles will go all haywire, and maybe dig the hole out more than you want, not to mention ruining the brush.

[Bob Glenn]

Give it a few days or weeks and it should resolve itself.

[Stew Denton]

Chris,

I think the idea of scrubbing the dog holes with an old tooth brush and solvent has some promise.

However, I think paint thinner would be a better solvent than acetone. Paint thinner, not mineral spirits, mineral spirit will be slower to evaporate. Toluene has better solvency properties than either the paint thinner or acetone, but is considered pretty bad for you. If your bench is in a location where the toluene can dry and the fumes not be a problem, it will be a better solvent for BLO. I am not sure how well the cured BLO can be removed by solvent, but again, the toluene has the best solvency properties.

Sew

[Charles Guest]

How much material did you remove from the benchtop when flattening it? The linseed oil in the holes shouldn't cause what you're experiencing. At any rate, wait until it's cured to see what happens then.

[chris carter]

I didn't take off much at all; probably a 32nd as it was relatively flat (flat enough to work on). I was about to install a mortised bench stop I got from LV and figured I should take care of any flattening first so I could keep the recess as minimal as possible and reduce the need to adjust it down the road after a flattening.

I did try scrubbing the holes with mineral spirits and a toothbrush and then wiping with paper towels yesterday. But I'm now thinking that really I just need to take a woodworking vacation and let it cure and see what happens. If it's still like this in 2 weeks, then I'll tackle it then with some alternate plan of action.

[Jeff Ranck]

can you make your holdfasts rougher so they are grippier? Maybe attack the problem from a different angle.

[Jim Koepke]

Did any of the residual BLO get on the holdfast? This could be part of the problem.

One of my first thoughts was to fill the dog holes with a fine sand. Hold a can underneath to catch it when it comes out the bottom. Not sure this would add to the holding ability or not. You could try it on one hole as an experiment.

jtk

[Charles Guest]

Stop the holes with glazing putty and fill them with turpentine. Let it evaporate or leak out, whichever comes first. Then wait several days before trying to use the holdfast.

[chris carter]

Well, this is interesting. I have two rows of dog holes and they are different depths. The front row is 2” thick and it runs above one of the pipes from my twin-screw pipe clamp vice which doubles as a tail vice; it is basically only receives dogs. The other row about 6” off the back of the bench are spaced far apart and are where I use my holdfasts and only the occasional bench dog. This row is 4 ½” thick. The bench is made from construction lumber (SPF). I tried a holdfast in one of the 2” thick holes and it held fine. So what I’m thinking is that the holes that are 4.5” thick worked perfectly fine when there was ZERO oil, but now they are just out of tolerance because of the BLO. I knew that 4.5” was at the upper limit, but I wasn’t concerned because I could counter bore them if necessary. It seems it might become necessary now. It’s irreversible, so I will try and wait another week or as long as I can to see if the problem solves itself first before I try and drill the bottoms bigger. It doesn’t sound like it would be fun either – trying to drill a hole upsidedown in a smaller hole that already exists is not my idea of a good time. If it gets to that point I’ll be seeking advice on how to keep the drill (power/spade bit) steady when there’s no center to anchor it down.

In the meantime, I’ll cross my fingers that a couple weeks of curing will do the trick. It seems to me that with all the projects I’ve done, at SOME point I must have gotten a more than a few drops on a hole before and maybe it was just that I didn’t wind up needing that hole for a couple weeks and so never noticed an issue. That’s my thought anyway.

[William Fretwell]

I don't know if you have a heat seal air gun, it gets much hotter than a hair dryer. Direct it down the holes to speed up adsorbtion into the wood. You could try increasing the holdfast spring pressure and painting the holdfast with rubber contact cement and let it dry to increase friction.

[John Kananis]

Which holdfasts are you using? 4.5" is a lot of bench-hole. The holdfasts may have just been holding before this incident; what about taller stock though? I would consider counter-boring (just like you were contemplating).

[chris carter]

Which holdfasts are you using? 4.5" is a lot of bench-hole. The holdfasts may have just been holding before this incident; what about taller stock though? I would consider counter-boring (just like you were contemplating).

I'm using the Gramcery ones, lightly sanded with 100 grit. I think that may be what's happening. I think perhaps when the holes had no treatment at all, the 4.5 deep holes were never an issue; impossible to pull out by hand and typically took a good solid couple of whacks with a mallet to release them. I suspect I may need to drill out an inch from the bottom. But I don't NEED the holes for at least a few more days so I'm going to hold out as long as I can before I go down that path and see if some curing time will take care of things.