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I have several quotes for 1/2" x 16" lag screws (+ 1 washer for each).
Portland - $1.35 each - Grade 1 steel
Instock - $2.12 each - Grade 2 steel - $2.95 each - Grade 2 steel.
A few quick questions:
1. Is Grade 1 strong enough for 11" logs - Swedish cope - Saddle notched.
2. The Portland Bolt rep ensures me that Instock and Fastenal must be selling me a Grade 1 (even though they state Grade 2).  He states that every imported lag screw is only a grade one?  Any truth to his claim?

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Perma Chink Systems, Inc. carries a line of fasteners called Log Boss. They do not require washers, they are self tapping, and are coated with Teflon for ease of use, as well as to prevent discoloration of the wood. The cost is $244.35 per pail of 250 for the 16". I don't know what differentiates a grade 1 from grade 2. We promote our fasteners based on their ease of use, shear strength, and pull-out, not grade. Those specifics are on the attached sheet. I know that our fastners are manufactured by TruFast in Ohio, so are not imported.

Is the Portland Bolt rep telling you the truth? I don't know, since selling fastners is not my job. I am in Customer Service and Technical Support. I just know that many of the manufacturers use our fasteners for a reason. You can read more about them on our website, if you'd like.

Good Luck!

Merry Anne
Technically a grade 2 carries almost twice the tensile (stretching) strength of a grade one mostly due to tempering the metal. Is that needed in a log home to hold logs together I can't answer. The tempering also helps to resist twisting the lag screw when driven it. Once again how important that is I have to leave up to the experienced home builders. The tempering adds cost to the manufacturing thats why the difference. It's not cheap but if it were me I would go for the grade 2 with coating to make the installation easier.

I tried to download a chart but it failed. You can lookthem up on the internet or ask for the tensil strength in PSI for the same diameter screw from the suppliers. It's easier if you specify you want the SAE rating. I think it will be about 33,000 vs 57,000 psi in tensile but once again there is the twist factor, which isn't rated, might be the most important factor.

Imported bolts carry the same grade markings as the US if they are SAE rated. Some use metric in kilograms. Grade 1 and 2 will look the same on the head, so you can't tell by looking.

I would agree with the Log Boss suggestion. There is also the Log Hog. It is basiclly the same thing as the Log Boss. They can both be driven useing a 1/2" drill without predrilling. I have also recently found a lag calld Spax Lags. I love them. They have all the qualities of the Log Hog but bigger and can be driven without predrilling. They also have incredible holding power. If you use lags, you will have to predrill and also drive with a electric impact gun. VERY noisy. Also if you decide to go with the lags, do yourself a favor and buy a big can of WD40. Spray the lags befor driving them. It will make it easier for them to drive and cut down on the friction. I've broken alot of lags befor I figgured this little secret out.

Michael Collins
One more thing. Do not use a fastener that leaves thread in the log being fastened down. In fact you should have at least 2" - 3" of space for the log to slide on a smooth shank. Drive all your fasteners straight to allow for setteling.

Michael Collins

Trust the Portland Bolt Rep. The grade one is also known as a machine bolt. Yes, the lag bolt and carrage bolt will be the same. The machine bolt will not have any marking on the top of the head. Your next step up will be your grade 5 or harden bolt. This bolt will have three lines on the top the head. From there you go to a grade eight bolt. These will have five or six lines on top of the head. From there you go to your speciality bolts. All inport bolts must comply to the same standars and specifications.

If you use lag bolts and drive them in using an impact gun, be careful about letting the gun hammer on the head trying to drive it in deeper. I have seen cases where the gun has chipped off minute particals if steel and inbedded them into the surronding wood. Apply a water base finish and you could have a wall full of rust stains. Forget about the WD-40, won't do your logs any good if you miss, use soap.

Hope this helps.

Jim Bilyeu
Thank you everyone, good advice.
I have been using WD-40 for years with no problems. Another good product to keep with you for situations like this is Pam cooking spray (or something similar), its cheap, can be found easily and gets the job done.
Also the particals you speak of are true. The WD40 will stop this from happening. WD40 will eventually evaporate, not doing ANY damage whatsoever. Soap is messy and hard to handel.

Michael Collins
I am the General Manager at Portland Bolt and wanted to clarify some issues with regard to imported lag screws. Fastenal, Instock, and Portland Bolt are all selling the same basic imported 1/2 x 16 lag screw. They are mass produced in factories in Asia and have no grade markings on the head. SAE J429 grades 1 and 2 do not require any grade markings other than the manufacturer's identifier, whereas higher strength bolts (grades 5 and 8) require markings indicating their grade.

Here is a Fastener Identification Marking Chart.

Since imported lags are unmarked and mill test reports identifying their chemistry and mechanical properties (strength) are not available, we consider imported lags to be "ungraded". In other words, the only thing we can tell customers is that they are made out of steel. A fastener sales rep can tell you anything, but without certified mill test reports for the lag screws in question, there is no way to determine what grade they conform to.

Although we can't compete against the prices of imported lag screws, Portland Bolt manufactures lag screws in situations where customers require mill test reports identifying the specific chemistry and strength of the steel. Typically we manufacture to ASTM specification rather than SAE grades. SAE (Society of Automotive Engineers) is a specifying organization that covers fasteners that are typically used in automotive, equipment, machinery, and OEM applications. ASTM (American Society for Testing and Materials) is a specifying committee that covers fasteners for construction applications.....such as log home construction. Most of the lag screws that we manufacture meet the requirements of ASTM A307 grade A, which is essentially a "standard" grade of faster similar in chemistry and strength to that of an SAE grade 1 or 2. However, custom lag screws can be produced in a variety of ASTM (or SAE) grades.
Hello James,

A grade is what is given to bolts to identify shear and tensile strength, and a lag bolt is a cousin to regular bolts and follow the same grading. Your most common bolts are grade 2, 5, and 8. The lower grade 2 is softer than a stronger grade 8, but the grade 8 is more ridgid. Because of the potential lateral movement of wood, engineers require a softer grade 2 or 5 for more deflection or bending. Log and Timber screws are oversized wood screws. They are heat treated to case harden the screw to give it strength, but yet has deflection capability without snapping. That is why you can use a smaller diameter log screw than a lag because of its strength. One value you do loose in a smaller diameter would be withdrawal. My company Log & Timber Connections carries the ASSY Log & Timber Screw that ranges from 1/4 to 1/2 diameter and up to 39" in length. Check out my blog at Always willing to answer any questions!

Best Regards,

Hello Will,

I just finished looking at your site. I am a builder/dealer. Can I get sampels of your log screws? I'm going to be starting a home in about 3 weeks and would like to try them. Contact me at

Michael Collins
Hello Michael,

Sorry for the late reply. I failed to follow this discussion. I'll get some samples to you this week!

Will Leverett


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