Author Topic: Use of Various Timber Screws for Green Stack Log Construction? (Read 1351 times)

kantuckid · « **on:** December 30, 2017, 05:29:50 PM »

I have previously (35 years ago) used 12" nails spaced along green pine logs in stack log construction after pre-drilling for settlement.
Now that many brands of various timber screws have come into common use, both hex and Torx head drive, my question is can these be logically used with green logs?
Or do the threads/friction, interfere/prevent the natural process of logs settling as they dry?
What say you experts

GAB · « **Reply #1 on:** December 30, 2017, 07:29:07 PM »

I have never built using logs and screws, however I would suggest that the head of the screw be counterbored into the log a minimum of the potential maximum shrinkage of the log(s) being used. Otherwise you could possibly end up with a lot of gaps between the logs.
Gerald

Don P · « **Reply #2 on:** December 30, 2017, 10:30:26 PM »

The various timber screws for log home construction have a smooth shank in the upper log and the rolled threads in the lower log. With the head countersunk to allow for some settlement the log should be able to slide down the smooth shank, if the screws are all set vertical. I prefer to use lag screws in prebored countersunk holes. There is more wiggle room in the upper log, I would prebore at 1/2" for a 3/8 lag. The counterbore was large enough to allow for a washer under the head of the lag and deep enough to allow for settlement. The lag has more pull down compared to the timber screws. On jobs where the supplier used timber screws we would bring along lags to use on troublesome logs. Any of those threaded fasteners does a better job than spikes at pulling things down tight.

kantuckid · « **Reply #3 on:** December 31, 2017, 11:51:41 AM »

GAB- With my home, I used 12" spikes which did work to pull down the logs OK. Cut off handle and a 6# sledge.
The technique I copied was used back then by kit homes. I used 3/8" dia spikes and a small auger bit to pre-drill slightly past the 12" depth for settling room for the spike. not about "head space", more about a hole to ease the spikes moving downward over time.
FWIW, I built a timberframe addition to my home in 2006. that involved removing a 10' or so section of log wall for the entryway. As I took apart that wall section, I could see that the spikes and pre-drilled holes did what they were supposed to do after the time from building in 1979-80 with winter cut, green logs. I don't recall having a need for pulling down a log or at least it got done using spikes.
The larger challenge was staying "corner's level" while using logs sawed on a circle mill and not perfect 6" thicknesses.
Don P-
I see that most all the log screw brands use a smooth shaft above a smaller threaded portion. A screw thread still seems to me a hindrance, head space or not, smooth shank or not?

The question becomes:
Does the log wall weight push the threads downward into the log below? With a countersunk hole above the upper log cannot exert any push on the head of the screw to cause it to penetrate further in my minds eye? Maybe the answer is a simple deeper pre-hole than screw length?

GAB · « **Reply #4 on:** December 31, 2017, 12:24:17 PM »

Kantuckid:
As I wrote earlier I have never built using logs and screws, but in my mind I can just envision the screws being held in the wood by the threads and as the wood dries and shrinks if the heads are not low enough to offset the shrinkage factor for the wood being used I can envision the screw heads acting like little jacks keeping the logs from remaining properly seated.
You mention kit homes - were the logs kiln dried. If they were then my concern is no longer a factor.
You also mention countersunk hole - I'm having a problem envisioning what you are saying. Did you mean a counterbored hole.
Countersunk hole has a tapered seat while a counterbored hole has square seat.
Gerald

kantuckid · « **Reply #5 on:** December 31, 2017, 12:58:44 PM »

I get what your saying but only if the screw doesn't move downward, penetrating the log below during shrinkage of the wall logs.
My home is not a kit. It came from an even aged stand of CCC SYP planted in my area during the depression. I peeled the logs on two sides by hand with a draw knife after sawing to 6" thick. My ceiling joists are in the round with a small flat sawn on one side.

I'm going to call some of the specialty screw companies next week and get their take on using them in green stack log walls. I'm a lifelong woodworker and a true wood freak but the screws came out ~ 1995 long after my build was done. I did use timber screws in my timberframe addition along with waxed, kiln dried, oak pegs-they were much easier to buy than turn myself!
OK, call it counterbored.
I saw a google you tube video of a kiln dried kit where-in they were counter boring screws into the top of the molded logs, The chuck of the drill was entering the counterbored area so it was much larger than the screw head, maybe ~ 1.5" or so? I'll not be doing that as it seems over kill to me?

Don P · « **Reply #6 on:** December 31, 2017, 08:15:37 PM »

Quote from: kantuckid on December 31, 2017, 11:51:41 AM

Does the log wall weight push the threads downward into the log below? With a countersunk hole above the upper log cannot exert any push on the head of the screw to cause it to penetrate further in my minds eye? Maybe the answer is a simple deeper pre-hole than screw length?

The screw is fastened to the log below and never goes deeper into that log. The log the screw head and shank are through is free to slide down the smooth shank as that log shrinks. The head needs to be an inch or so below the top surface of that log so that as it shrinks and drops the screw does not protrude above the top surface of the now shrunken log and hang up the log above it... that is what the counterboring business is about. Some folks put essentially valve springs between washers on the lag and run that all down into a deeper counterbore, still with headroom above the fastener. As the logs shrink the springs apply downward pressure to keep the logs snugly together.

One thing to remember is that if the fasteners of whatever type are not vertical but at various diverging angles, the log cannot slide down. That is desired in some methods of log construction where they pound in rebar in smaller sized holes all the way at angles to prevent settlement from shrinkage. They then chink the gaps. Doesn't rock my world but to each his own.

I've also built with allthread from underfloor to top of logs with a heavy washer top and bottom and supposedly the homeowner will keep those nuts snugged down. There can be springs under the washer on these setups too. Not sure I buy the spring thing but some folks swear it works.

kantuckid · « **Reply #7 on:** December 31, 2017, 08:59:54 PM »

Springs seem like a wrong minded approach to wood movement for my brain. I did look at a kit build onsite many years ago that used long all threads. I'm beginning to see the light with the screws from your dialog.
I have 50#'s or so of the 100 penny-3/8" spikes from years ago. Might use them up down low then switch to screws higher up for less climbing and beating.
Now moving to>>>>
Torx vs. hex head? I've used lots of the smaller sizes of coated torx scews from 1" up to 3" length-the gold ones. Also used the hex heads on my timber frame LR addition but none that were longer like 10"-12".
My son the civil engineer is now reading the other thread towards foundation stuff-he has three young kids to keep him busy. He says he'll only comment off the record as KY not one of his license states

and he doesn't want the "heavy hitter" suing him.

Don P · « **Reply #8 on:** January 01, 2018, 12:29:15 AM »

Understood, you need his brains not his stamp here. Bonhoff on shallow post foundations might help if he's studying. I also recognize that their job is, to paraphrase Walt Whitman, to revel in their light strong work. I use them as a jumping off point and often do them one better.
I prefer driving the 5/16 hex drives, "log hogs" are a little larger than olylogs and timber screws, a little bigger head, you can washer any of these, but those are more expensive. The "pull down" power is all about thread diameter so these pull down more without stripping out. Even there I like to have some 3/8 regular lags handy for ornery logs. Since they are about half the tensile strength steel of the small black screws they tend to break before stripping, they are around 45ksi steel where the timber screws run around 90ksi so although they pull down better they are more fragile.

Watch your lower logs that you are spiking and if you can't snug them down run a few screws as needed. I punch spikes below surface when using them for the same reasons as above, I don't want the heads possibly hanging things up later. If you have access to a Hilti or one of the demo hammers you can weld up a cup to fit over the spike to do most of the driving.

On a couple of houses we've used screws to suck the logs down and hold alignment while building but have also drilled 1" holes from bottom to top at corners and beside openings as we built and then tapped allthread down through the stack when done. A couple of the kit companies put a coupler on the top of the foundation J bolts and hook the allthread to that, positively tying the log walls to the foundation.

I had dinner last night with a family we built for a dozen years ago. I've sat around that table with 4 generations under my roof. Within a very short stones throw 3 other families were I'm sure gathered in the same way under my work. We passed others on the way. One very harsh day, my final exam will happen. Some have been through that storm, I hope. Build well

.

kantuckid · « **Reply #9 on:** January 01, 2018, 04:59:44 PM »

What is the best choice of length for a 6" log thickness , using a flatheaded screw or small hex thats buried into the log? The screw sellers say to make certain that all the threads enter the log below which to me means a 9 or 10" screw will do the trick.

Don P · « **Reply #10 on:** January 01, 2018, 06:41:13 PM »

This is the engineering services report with all the specs, depending on which one you use, the fastenmaster line has 2" threaded the loghogs have 3 and you are countersinking. I'd use a 8 or 9", no harm going longer other than to your wallet.;
http://www.icc-es.org/Reports/pdf_files/load_file.cfm?file_type=pdf&file_name=ESR-1078.pdf

kantuckid · « **Reply #11 on:** January 02, 2018, 09:46:06 AM »

Now the conversation turns toward Log Hog w-3" threads/larger shank/more $$$ vs. Oly Log w-2" threads/smaller shank/less$$$ vs. "Spax type" various Torx driven screws in similar price ranges??? I have used Spax screws in shorter sizes than 8-9". Pricey they are but also some Asian similar versions out there as seen on ebay.
I have zero knowledge of hex headed long screws in log or timber applications. I am a retired former pro wrencher so know hex heads-HA! Worn out hands as exhibit "A"!
I'm also a life long woodworker who has learned to love Torx driven screws and hate on SQ drive & Phillips screws.
Side story on screws-I bought some long SS SQ drive screws to use on Red Cedar (acidic wood) and found the longer ones are too soft even when pre-drilled! The shorter ones on Red cedar flooring were OK though

Obviously I'm after field experience here-boots & suspenders talk as to if the stronger screws are actually needed, what drives best, so on?

Edit note: In talking with a log home supply house just now,, I was told that the Oly Log screws were suitable for a non-earthquake prone location like mine.
Now I am comparing the Oly Log's with the similar TimberLok screws and the other style-Torx head/ Spax style screws?

Don P · « **Reply #12 on:** January 02, 2018, 08:39:57 PM »

Pull down, or withdrawal strength, is about wood density, diameter and penetration. The one has 2" penetration, the other 3" and also larger dia, you can see the difference in the spec sheet above. That is real and you'll feel and see it in the field, that is also why we would travel with cases of lags as well, bigger dia and more thread, that was coming out of my pocket but well worth it. You can do most fastening with the regular screws and have some loghogs and lags for tough spots. Now bear in mind we were assembling milled logs and one of our selling points was dead flat wall stacking and dollar bill tight everywhere.

If you go with off brand fasteners get a few samples of them and olys, chuck em in a vise and bend. Some of that stuff old car bumpers and railroad tracks. I prefer hex drives but either works fine.

Tell me about wrenchin

We've got the NOS deutz 2 cy diesel in and bolted to the pumps in the loader. Wires to the forward/reverse solonoids, filters and fluids and we should be ready to test fire it tomorrow. Off to degrease me and take a few asperin to get over the contortion aches

kantuckid · « **Reply #13 on:** January 03, 2018, 01:45:21 PM »

I am now wondering how strong of a 20v cordless impact driver it takes to run these in? I don't own one of those as my drill drivers do fine in wood shop stuff but thinking it would be a great modern tool addition to my pile of stuff.
The ones I'm looking at start around 1,300-1,400 inch pounds and go up from there in power and quantum leaps in price too!

Don P · « **Reply #14 on:** January 03, 2018, 04:48:49 PM »

Dunno, I've run a few with a DeWalt battery impact but when running them on a house we used my big, slow speed 1/2" drills. I just got a Kobalt (lowes house brand) 20v drill driver combo, it has a 5 year warranty on the tools and 3 on the battery.

Ran a whole new harness. Artie purrs, or putts, like the African Queen

starmac · « **Reply #15 on:** January 03, 2018, 05:10:40 PM »

My son started out a few years ago buying dewalt, so when he went with a 1/2 in impact he stayed with dewalt because of the same batteries.

I have done the same except I went with milwaukii. I have probably 10 different tools so that many batteries, I can keep charged. He now wishes he had gone with milwaukii, but it would be costly to change over.
Milwaukii has several different torque levels for their half inch impacts, mine is the highest at 700 ft pounds forward and 1100 ft pounds in reverse. I am in the trucking business and use it daily at times, and unless doing tire work where I need the one inch impact, it is a rare day I drag out the air hose anymore.
When I first got my mill, I kept the service truck parked close and would use the air to blow off the mill occasionally, my wife bought me the milwaukii cordless blower, and it is one of the handiest tools a guy can have around the mill, no more cranking the air compressor.
I use it to blow off the lumber too, which I didn't do when I had to crank the compressor.

kantuckid · « **Reply #16 on:** January 03, 2018, 05:22:09 PM »

Historically I like Milwaukee and own a saw, router and drill-all pro level, USA. I bought each of my 3 sons a Milwaukee cordless drill set a couple years back and I think only one is still alive now and they are DIY only use. Turned me off from the brand!
I am buying an Impact driver not an impact wrench in this case. I already own a couple of cordless drill drivers but they wont do real long screws, like above 3-4" or so.
The whole battery thing is a PITA with cordless tools, even my Libertarian brain wishes the guvment would get them on a similar path.
Has anyone tried the generic batteries?

btulloh · « **Reply #17 on:** January 03, 2018, 06:14:52 PM »

I tried some generic batteries for my 18v dewalt stuff. Not bad so far. I got a couple 18v 3ah batteries for $45.00 and they are what they say they are. Time well tell. The fit was a little different, but acceptable. Overall it was a good purchase. So far. I'm in transition to makita Li-on stuff, but I still have lots of life left in Dewalt tools and I'm trying not to spend another fortune on batteries. (The makita stuff is good as long as you stay at the high end of the line. True of all the tools now, really. I wish I had looked at the Milwaukee Fuel line and the new Dewalt stuff before I switched. The makitas are good, but they don't fit my hand right like the Dewalt tools.)

I've driven a handful of 8,10,12 inch timber screws with various cordless tools. The 1/4" impact driver will do ok, but I wouldn't want to drive more than a couple with it. Not enough power really. The 3/8 impact tool was better, but still not up to building a log wall. 1/2" drills are ok, but still not good for doing a bunch and all the torque comes back at you. I see the big Milwaukee rt angle corded drill used by people in the biz and it looks like a good tool for the job.

Don P · « **Reply #18 on:** January 03, 2018, 07:20:14 PM »

I've got the Milwaukee rt angle Hole Hawg as a backup but prefer to use the Makita clutched rt angle drill. DeWalt makes one as well, I had the B&D Timberwolf prior to the DeWalt buyout which is the same drill DeWalt is offering now in yellow. One of those is a better all around drill, the clutch can save you a broken wrist when you get to bigger drilling jobs on the house like holesaws and it is more comfortable to use than the Milwaukee, but either has the torque.

MbfVA · « **Reply #19 on:** January 03, 2018, 10:11:47 PM »

I think I've got some age on some of you guys:

Break my wrist… Make my day

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Author Topic: Use of Various Timber Screws for Green Stack Log Construction? (Read 1351 times)

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