This post is in response to Harvywallbanger’s question about the insert, or “sleeve” in the end of the GCIII rail that is used to bolt the pocket castings to the end of each rail. While the bulk of this thread has been about the problems with the rail nuts, HWB’s point is a valid one considering that GC IIIs, especially those in commercial use, are plagued with the same problem HWB is referring to.
PROBLEM
The daily ball pounding and vibration the pocket castings are subjected to and the very low torque it takes to inadvertently loosen or even remove this insert, combined with the relatively soft poplar wood Brunswick used to mill the sub-rail make this an ongoing problem. Attempts to use epoxies, bondo, wood putty, etc. to reseat the original insert are usually short lived. Mechanical fixes such as driving in screws or ring shank nails next to the insert are sloppy, unprofessional, also short lived and aggravate the already compromised hole in the poplar sub-rail.
ONE SOLUTION
If the original hole in the sub-rail has not been compromised by extreme wallowing, splitting or splintering, a relatively easy on-site fix can be achieved using Stafast replacement insert SK381630HD (steel insert 3/8-16 x 30mm HX Drive). This is a fantastic part, machined out of steel, with massive external threads that really bite into the wood and a hex head driven end. Compared to the cheaply cast original inserts, or even the hardware store machined brass inserts with a wimpy slot for the driven end, these inserts are amazing. Plus, because of the large diameter of the external wood threads, they are ideal for this repair. You will need a good variable speed cordless drill, a 5/8 inch FORSTNER bit, a 10mm hex driver fitted to a 3/8 inch ratchet with a 6 inch extension, and a tube of 5 minute epoxy. We usually replace all of the pocket casting inserts at the same time, charging appropriately for this service.
IMPORTANT! In the following step, DO NOT attempt to use a 5/8 inch spiral bit as it will bite into the existing hole and drill all the way through the top of the rail in an instant! Spade (flat) bits are equally problem prone as they will not cleanly chase the existing hole without chattering and the point of the bit will penetrate through the top laminate.
First, prepare the existing hole by carefully chasing at the same angle with the 5/8 forstner bit. The new, enlarged hole will have to be slightly deeper (30mm total depth) to accommodate the longer length of the Stafast insert. If you are unsure of your drilling skills, it is safest to fix a depth stop around the shank of the bit and make some test holes in a scrap of wood. A cut piece of pipe or tubing or a ½ inch drive socket works good for a depth stop. Keep in mind that this is a one chance process and the consequence of mis-drilling is an unsightly hole in the top of your rail. Once the holes have been prepared, thoroughly blow them out with compressed air or a soda straw so the new inserts will seat properly.
To install the new inserts, first clean them in denatured alcohol or acetone. This is necessary because the SK381630HD is a machined part rather than the cheaply cast original inserts and has a machining coolant residue on it. Next, carefully align the new insert with the hole (this is the purpose of the 6 inch extension on the ratchet) and thread it in until it bottoms out. Do not force it past the bottom of the hole or it will split out the sub rail and cause a bulge in the laminate on the top of the rail.
Now, back the insert all the way out of the rail and apply a thin coat of epoxy to the newly cut thread in the wood. Using epoxy keeps the insert from threading out and reinforces the wood threads. I like using the super glue for this but it is risky if you cannot quickly reinstall the insert without stopping. With super glue, I use a 3/8 inch impact wrench to final set the inserts. The epoxy is safer to use but does not penetrate the wood threads as deeply and there is greater risk of fouling the internal threads of the insert. In either case, check the internal threads and chase them with a 3/8-16 tap if needed.
Now you can align and firmly tighten the pocket castings to the rail ends. Do not blue torque them or you will risk pulling out the new insert. If need be, you can always tighten them up again after the table is fully assembled with a 9/16 inch wobbler socket and extension. During assembly, use domed washers or thick fender washers that over lap all three edges of the pocket casting without falling into the void. Standard 3/8 inch washers have too small of an outside diameter to be used here. Also, many bolts are not threaded all the way to the head, leaving an unthreaded “shoulder.” Make sure the shoulders of the bolts you are using aren’t running into the insert.
Final Note: When the existing holes have been compromised by extreme wallowing, splitting or splintering and they are already too big for the stafast inserts, there are other solutions that can be used. Hope this helps, KR
