Frequently Asked Questions

General FAQs

Does the use of lag screws with split rings affect installation?

Split rings are designed to be installed with standard machine bolts and nuts, but they can also be used with lag screws.  One thing to take into consideration is how the use of lag screws affects installation.  When installing lag screws, you need to drill a pilot hole to prevent the head from breaking (Lag Screw Pilot Hole Diameters).  This causes an issue when installing split rings because the size of the pilot hole for lag screws is different than the hole drilled for bolts. 

For example, The use of a  4” grooving tool requires a 13/16” pilot hole, but the pilot hole for a ¾” lag screw is ½”.

Section 12.1.4.2 of the American Wood Council’s National Design Specification for Wood Construction reads as follows:

“Where lag screws are used in place of bolts, the hole for the unthreaded shank shall be the same diameter as the shank.  The diameter of the hole for the threaded portion of the lag screw shall be approximately 70% of the shank diameter”

For example, if you have a ¾” x 12” lag screw with standard 6” thread length, you would drill a 12” deep pilot hole ½” in diameter then re-drill the top 6” of the hole 3/4” for the shank of the screw.  However, the pilot bit on the grooving/dapping tools is 13/16” in diameter.  Therefore, you will need to check with your engineer to determine if the top portion of the pilot hole can be drilled large enough to accommodate the 13/16” pilot bit or if you will need a custom pilot bit made that will fit into the ¾” diameter hole.

Can I use pitch diameter bolts with split ring timber connectors?

Often bolts 10” and longer are made with reduced bodies and full size threads. These are bolts where the unthreaded shank is equal to the pitch dimeter of the threads and the threaded portion is equal to the nominal diameter. This is allowable per ASME B18.2.1 dimensional tolerances and ASTM A307 Grade A hex bolts. However, The American Wood Council does not allow this when used in conjunction with split rings. In section 13.1.3.3 of the 2015 National Design Specification for Wood Construction, it says, “Bolts used with … split ring connectors … shall have an unreduced nominal or shank (body) diameter in accordance with ANSI/ASME Standard B18.2.1.” If you are going to use reduced body bolts, you will want to confirm with the project engineer that this is allowable.

Can roll threaded bolts with a reduced body diameter be used with split ring timber connectors?

No. According to Section 12.1.3.3 of the American Wood Council’s National Design Specification for Wood Construction, a bolt with a full body diameter must be used with split rings.

12.1.3.3 Bolts used with split ring and shear plate connectors shall conform to 11.1.3. The bolt shall have an unreduced nominal or shank (body) diameter in accordance with ANSI/ASME Standard B18.2.1 (Reference 7).

Are more sizes available?

They are not.  As an engineered product, split rings only come in the 2-1/2” and 4” variety.

What are the relevant dimensions for split rings, other than the diameter?

The 2-1/2” are approximately .17” thick and .74” high, while the 4” split rings are .21” thick and 1.10” high.

Are other coatings (zinc, dacromet, etc.) available?

Not off the shelf.  Portland Bolt stocks both plain finish and hot dip galvanized, if your project requires a different finish, let us know and we can work with you to get the finish your project requires.

Are stainless steel split rings available?

In very limited quantities, and at a much higher price and longer lead time than galvanized or plain.

Do I have to use a Grooving Tool?

Yes. As split rings have a slight curve to them, without the proper tool, your split rings will not fit properly and you risk damaging them during installation.

Is a drill bit sold with the grooving tool?

A drill bit is not included with grooving tool, a pilot is though.

Are Split Rings domestically manufactured or imported?

Both are available.  For the vast majority of projects import parts should be fine, if your project does require domestic hardware, be sure to let us know and we will be happy to help.  No matter the country of origin of your split rings, there will be no difference in quality, the only difference will be that domestic split rings are much more expensive.  If you are not sure if your project requires domestic hardware, please refer to this article on our main website.