Re: Hardened lag screws

There can be more to using lag-screw that getting a wrench with a longer handle. The following discussion might help.

In most uses, lag-bolts make a one-way trip. Obviously yours are working well. You can do several things to reduce their grip.

Not all lag bolts are equal. You might try using those with the shiny plating rather than those with the rough dull gray coating. The bright plating is smoother and gets less grip into the wood, making them easier to remove.

Use shorter screws.

Drill larger pilot holes. 1/32 smaller than the outside diameter of the thread is plenty for our use in all but the softer woods. In other words, a 3/16" hole for a 1/4" lag-bolt isn't large enopugh. It would be better to use a 7/32" drill.

Drill the pilot hole to at least the same depth as the length of the screw.

There is always the problem of green wood drying and tightening around the screw for a tighter grip. The solution: don't leave the screws in the wood for long lengths of time. If you have to set the piece aside for a couple days, loosen the screws; and remember to tighten them again when you put the piece back on the lathe.

There is always a problem of oxidation of green wood that is in contact with the plating on screw. This will show up as the wood around the screw turning black. The oxidized wood will form a strong chemical bond with the screw, making it harder to remove. Dragging the screw threads across a block of beeswax several times, or rubbing them with some paste wax, before screwing them into the wood will help to solve this problem.

Harder lag-bolts without doing anything else could make the problem worse. Harder lag-bolts are not plated and you can have corrosion to contend with in green wood. This can have the effect of making them harder to remove. Should you go this route, make sure that they are waxed before screwing them into the wood.

I use the hard screws for no other reason than they can be re-used for years without rounding the hex head on the screw.

That's everything I know about using lag-bolts.

Russ Fairfield Post Falls, Idaho

I use 1/4" x 1" hex head lag screws through a 1/4" thick faceplate. I drive them with a cordless drill. I don't use a socket wrench at all. I break one screw about every 30-50 bowls. The threads gradually wear down from going through the faceplate. I never pre-drill. The screws are just normal cheap ones.

Derek

Why use lag screws at all? I use SPAX screws exclusively and have yet to have one break off in a piece. You can get the SPAX screws at Home Depot or Highland Hardware in Atlanta - they sell them in boxes of 50 or 500. These scews have phillips/square drive heads - I use a square drive in my drill and they work great - hold great and never break. The ones I use are #12 &

1 1/2" length. The faceplates I use are One Ways that have either 8 or 16 holes.

Additionally, I think you may be better served by mounting your bowl between centers before mounting the faceplate - that way you can true up the top/bottom and adjust the center points to ensure that the wood's grain is properly aligned. By proper alingment of the grain, I mean you should be seeing a distinct H pattern in bowls that have the base to the bark side and a bullseye pattern in bowls with the base to the pith side. By mounting between centers, you can acheive a distinctive pattern that makes the bowl that much more attractive.

These are just my opinions and should be taken in the spirit that they are offered.

Ray

Tim,

It sounds like you are turning gigantic bowls if you are using lag screws to fasten them to the faceplate. But you mention using #6 or #7 hardened lag screws. I have another suggestion. Rather than go to a different lag, try some comparably-sized sheet-metal screws. They are threaded all the way to the head, have a shallower pitch, generally, than lag screws, and, IME, seem to grip better, in that application, than a wood screw of the same size.

Try using some beeswax for a lube, too, rather than the wetter liquid soap.

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

mount the blank with a faceplate **** lag screws that break *** I generally use some kind of lubricant, >like a little bit of liquid soap. *** the head just twists off.

soap is the wrong thing to use as a lubricant. it's slippery going in, but it reacts with the wood and with the metal, and the products of that reaction are anything but slippery.

try paste wax.

I also use sheet metal screws exclusively. Hex head, #10, by whatever length my workpiece will allow up to 1-1/4" long. Never needed any longer, and never broken one after dozens of reuses. I like the hex heads because I can retorque if needed without removing from the lathe. Oh, I never predrill either, and drive them in and out with a drill/driver.

--

I use lag screws with a faceplate on heavy items (say 60 to 150 pounds) and use the tail stock also. I found that just using #10 or #12 screws doesn't work very well - they tend to shear off and then you have a heavy moving object to contend with, but that never happens with the lag screws. And, I've had very few break - I don't lubricate and I don't predrill - I hammer them in part way to get them started and drive in with a socket wrench. When one does break, I just leave it there - I'm not going to use that center core for anything anyway, just cut the center out with a slicer, or cut from the edge in until you are below the lag screw and then cut into the center -

snip

I've been using Spax screws for large vases lately and have been impressed with them so far. I also use the 1 1/2" through a 6" Oneway faceplate. I forget how many holes it has but it's quite a few, maybe 24. I turn green big leaf maple vases, end grain, in the 18" tall range and maybe 10" diameter and haven't had a failure yet other than one that I tightened too much and it stripped the wood. I use a cordless drill with a clutch to drive the screws with no predrilling and then check the tightness by hand before mounting on the lathe. The blanks are turned between centers to cylinder before the faceplate is mounted to them.

- Ray