Welcome! Forums Project Series Workbench Jaw liners keep splitting

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    While trying to fit jaw liners to my Eclipse vice following Paul’s latest workbench build video I have had two of the small 1 inch side pieces split and one end of the rear jaw liner split where it attaches to the 1 inch side piece. I am using mahogany and drilling pilot holes larger than I usually do in attempt to prevent the splitting, but not having much luck. If you attached these, what kind of wood did you use? Did you have any trouble with it splitting, or tips to prevent splitting?

    The first time I split the side piece I had it oriented so that the grain ran vertically (with end grain on the top). The second time I had the grain running parallel to the benchtop. Both split. It just seems like the 1 inch side pieces are too short to accept screws (since it puts them too close to the end grain). This also means that the rear jaw liner has 4 screws close to the end grain.

    • This topic was modified 1 year, 4 months ago by sailforfun15.

    Some reasons that come to mind:
    – the predrill size too small — you said larger than usual holes used but then I cant imagine how it can split unless:
    – no countersink
    – over tightening — its wood, can’t take too much torque, use a manual screw driver.
    – wood too dry

    For the side pieces these are clearance holes, so larger than usual pilot hole sizes. Holes that snug fit the screw shank should work well. I used some scrap oak (1″x3/4″ x ~4″), grain along the long dimension, no pilot hole in the apron, clearance hole of 5/32 in the oak pieces for #8 GRK screws and no splitting. I don’t think it would split with even smaller (say 1/8″) holes.

    Nice profile photo, by the way 🙂


    Keith Walton

    did you countersink?Screw heads are like a wedge some times if not.


    Thanks for the suggestions. I eventually figured out that the small side pieces should have clearance holes. I had already countersunk them. I think my wood is dry–I’m using mahogany off-cuts I’ve had in my shop for 9 years or so. Though I am in Houston, where low humidity is around 50%. The other issue I’m having is that I am adding this to a Sjoberg bench, not Paul’s workbench design with the wide aprons. The bottom most screws for the inner liner extend below the apron of my bench. You can see how much the vise extends below the bottom of the bench in this photo with the bench upside down. As a result, the bottom screws on the inner jaw liner can only bite into the short end pieces. My last attempt split one of these.

    So… watching Paul’s older vise installation videos I saw that he used only one screw on each side of the inner jaw that goes all the way through both the inner jaw liner and the side piece. I am going to recut the inner liner and side pieces and then create clearance holes through both then drive a single screw through and into the apron.

    This has been one of those things where I never expected something that seemed so simple to cause so many problems. My installation is now over a week long, but most of that was because I had to repair the poorly designed workbench top to leg connection and flatten the top of the bench. I was tempted to put the top on my Shopbot CNC for flattening, but in the end I think I was better off with my jointer and jack planes.

    I will be sure to post a followup with photos in case anyone else runs into this snag.


    I’m happy to report success. Using a single clearance hole through both the rear face and the small side pieces I was able to get everything into place with no splitting. I used thin one inch screws to put the front liner on using pilot holes before screwing it in place. To position everything it really helped to double stick all 4 pieces together. Despite (or perhaps because of) the difficulty I had, I feel quite good about getting this done and I’m happy with the results.

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