Screw choice for END-GRAIN Bradford Pear?

Re: Screw choice for END-GRAIN Bradford Pear?

mikeee12345

No fun digging broken screws out of a wood piece, stainless steel screws would be a better choice to provide holding strength while turning on the lathe and not break when installing or removing the screws from the wood piece.

Rarely

Mark Mandell - Gone Round In New Jersey

use a face plate any more, but wet or dry I use #12s that will penetrate 1" or more into the wood. Deck screws are too thin, usually #8 and too weak to handle the stress from a turning. My FP's are 1/2" thick and are double countered so I'll use 1-1/4 to 1-3/4" flat-head screws waxed. Lastly, I prefer to use the drill with the clutch backed off rather than the impact driver; easier on the screws and they hold better because you're not twisting them beyond their maximum grip point. The impact will torque too much and actually fracture the wood fibers turning the screw into a drill bit so you get less holding power.

That said, I start everything between centers so that I keep the option to adjust the rotational center and better balance the grain. For end grain work I'll cut a tenon to fit the DT jaws in the scroll chuck, especially in wet wood.

Doing a bowl or a jar?

Pilot Holes for End Grain

Doc Green

To get the best holding power in end grain wood: 1. Always drill a pilot hole; 2. Do not over-tighten the screws. (As Mark said above.)

I ramble on at length about it here:

http://www.docgreenwoodturner.com/screwendgrain.html

Good luck. ~Doc

Re: Pilot Holes for End Grain

Keith Newton

I did drill pilot holes, and obviously must have over tightened the first. However all the others broke off while trying to remove them, and even after the heads broke off, there was plenty left to get a good grip with vice-grip pliers, but they broke again.

Sometimes the wood can really seize onto fasteners.

Excellent article Doc-as are all or yours

Re: Pilot Holes for End Grain

Lyle Jamieson

Its not the length of the screws that will give you support it is the number of screws. I use #12 pan head sheet metal screws 1 1/4 inch long. But 10 or 12 screws in each faceplate. I have never had one break. I always use an impact driver. I only pilot hole dry wood. Pilot holes in wet wood end grain risks stripping the threads.

How long did you leave the screws in before you tried to remove them??

Use #12 screws because the heads are for #3 Phillips. They don't strip the heads while screwing and last many times before the socket gets scarfed up.

Not very long

Keith Newton

How long did you leave the screws in before you tried to remove them? The screws were not in the wood over 15 minutes.

Just to make it clear, my problem wasn't that my screw to wood connection failed, it was just the opposite. I felt the screws must have been faulty, and failed / broke too easily.

I think it would be safe to say that all woods aren't the same, when it comes to screws into end-grain performance.

Re: Not very long

Lyle Jamieson

The wood variety has very little difference in using the faceplate method. I have done the same method you describe thousands of times in wet woods of all varieties with no failures.

Re: Excellent article Doc-as are all or yours

Bill Turpin in WNC mountains

AMEN!

Re: Screw choice for END-GRAIN Bradford Pear?

Barry Irby

I have used pan head sheet metal screw Lyle describes and had no failures.

I have also used Tapcon screws meant to driven into concrete with no failures. For these I countersunk the holes slightly so I can use either pan head or countersunk screws.

You are right about the quality control though.

Re: Screw choice for END-GRAIN Bradford Pear? *LINK*

walta

Every screw manufacture balances hardness vs. toughness in their product. Both are desirable properties but generally as hardness increases, toughness decreases.

Hardness is the ability to cut into concrete or steel without damaging the threads on the screw.

Toughness is the ability to bend without breaking.

I test the screws I use on face plates for toughness by clamping half in a machinists vise, hit the screw with a hammer if it will bend 45° without snapping you have the correct screw.

Understand the tough screw will most likely fail because the Philips head will strip. I look for square drive screws.

A hard screw is very dangerous, because they will snap without warning letting the wood fly.

The only thing stainless offers is rust resistance at the expense of both hardness and toughness.


Craft supplies

Re: Screw choice for END-GRAIN Bradford Pear?

Lyle Jamieson

agree there is a balance there. I do not like square drive with a impact driver. The bit sticks in the holes and is a pain. The # 12 screws use a #3 Phillips and they are much sturdier than the #2, that strip easily.

Re: Screw choice for END-GRAIN Bradford Pear?

Keith Newton

None of my screws failed in the middle, so your test bend wouldn't likely show if you just bent it in the middle. I think you should also grip the head, and try to bend at the thread end, where all of these failed.

As for hardness and toughness, I think the subject is a bit deeper than your statement. Just mild steel might bend easy, but probably break easily too. I agree that toughness is what we need, and what I was hoping to hear about what others are using.

Back in my early years, I thought I would just bump on up and use Lag Screws. I quickly found out that 1/4" lags will break where the thread starts if you just look at them wrong. Lags might be fine at 3/8" and above, but then going that large would probably lead to other problems like splitting along the grain due to more wedging if the pilot hole wasn't sized properly.

I agree with Lyle, in that I had looked for the larger screws, which were loosely resting in my 10" faceplate, rather than making it back into a little tray where I normally keep them. After starting with the #10 screws which had #2 phillips that failed, I replaced them with the #12 pans.

Re: Screw choice for END-GRAIN Bradford Pear?

Doug Ladendorf

There are two quality screw brands I like that can be found at Home Depot:

Tapcon http://m.homedepot.com/p/Tapcon-3-16-in-x-1-3-4-in-Philips-Climaseal-Steel-Flat-Head-Concrete-Anchors-75-Pack-24355/100136988

GRK Fasteners http://m.homedepot.com/p/GRK-Fasteners-8-x-1-1-4-in-R4-Multi-Purpose-Screw-110-per-Pack-96080/204837653

The bigger GRK can substitute for lag bolts. They are great.

'Nuther Vote for GRK...

Brad Vietje

GRK makes a wide variety of fasteners. I only use the #8 screws for small, lighter work, but for 150# Aspen lamp shade blanks, I use their 1/4" x 3-1/2" and up through the bad boys that are 5" long. These are amazingly strong; tough w/out being brittle. (I had to demolish a temporary construction stairway that was made from 2x6's and the #8 x 3" screws, and I can attest that you can beat the living hell out of these, and they will bend a long way before they break. I gave up trying to break them apart with a #14 sledge hammer, and resorted to cutting them with a Sawzall and a metal blade.)

GRK is hardened steel that are very tough (some are available in stainless, which is not as strong). They use a TORX head, for great "grip" w/out stripping. For sheet metal screws, do get some that are #3 Phillips, which are many times better than the standard #2 Phillips -- I think Lyle suggested that(?), and I will agree.

Safe spinning,

Brad Vietje

Newbury, VT

Re: Screw choice for END-GRAIN Bradford Pear? *LINK*

Jim Barbour

How about SPAX screws? HD and McFeeley's carry them, as I am sure others do as well. I've used them in side grain, but not in end grain.


http://www.spax.us/

Re: Screw choice for END-GRAIN Bradford Pear?

r thomas

Why not use a chuck? I use a chuck on hollow forms up to 14 in and around 80 lbs.