Replies

1. 
   MBerger | Jul 27, 2007 12:17am | #1

   Hi Ken.

   I'll talk to the editor of this article tomorrow morning and get back to you with an answer but my initial thought is that the hex end of the carraige bolt should be countersunk into a square hole on the underside of the cleat and adjustable fence that prevents it from spinning when tighten the lock nuts.

   I could be off base so I'll doublecheck and get back to you.

   Matt Berger
   Fine Woodworking

2. 
   JohnWW | Jul 28, 2007 12:06am | #2

   Trying to get the small square shoulders of the carriage bolt heads to resist the considerable torque created by the lock nuts is asking for trouble. The MDF, especially when counterbored to bury the bolt head, is too soft to withstand the force of the bolt trying to turn.  In general I try to avoid using carriage bolts since they can spin in their holes too easily.

   The easiest fix at this point would be to skip the lock nut and replace it with two conventional nuts that can be locked against each other. 

   Another fix would be to replace the carriage bolts with hex head bolts with the bolt heads set into hex shaped openings chiseled into the back of the MDF, but the counterbores you made for the carriage bolts may already be too large to allow this.

   John White, Shop Manager, Fine Woodworking Magazine

    

   
   

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   Edited 7/27/2007 5:07 pm ET by JohnWW

1. 
   kenITR | Jul 28, 2007 12:48am | #3

   Thank you.Ken