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How to Drill Accurate Holes for Deck Post Bolts

Bob Jackson
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by Bob Jackson

I show how to drill accurate holes in a 6×6 deck post to install 1/2 inch bolts in the Simpson Strong-Tie PBS66HDG Standoff Post Base. This project is continued from How to Install a 6×6 Wood Deck Post. Also see the project introduction which explains the sagging wood deck problem.

How to Drill Accurate Holes for Deck Post Bolts

I didn’t think I could freehand drill a 1/2 inch hole through the 6×6 inch deck post to install bolts in the Simpson Strong-Tie Standoff Post Base, so I’d fastened the post with Simpson Strong-Tie SD #10 x 1-1/2 structural wood screws as temporary solution.

Wolfcraft Drill Guide

My solution was to buy a Wolfcraft Drill Guide Attachment from Amazon. For an under $40 tool it did really well. I used the combination square to check the drill guide was set at 90 degree and set a 3/8 inch spade wood bit in the chuck to drill a pilot hole:

Wolfcraft Drill Guide Attachment Model 452504 for Bolt Holes in Deck Post Simpson Strong-Tie Standoff Post Base PBS66HDG
Wolfcraft Drill Guide Attachment Model 452504 for Bolt Holes in Deck Post Simpson Strong-Tie Standoff Post Base PBS66HDG

The Wolfcraft drill guide has a raised base that fits over the Simpson Strong-Tie standoff post base. I recommend using wood spade bit to drill the pilot hole because a twist bit will pull too aggressively into the wood and bind. By contrast the spade bit doesn’t pull itself into the wood and gives you more control. I drilled a the smaller 3/8 inch pilot hole in case the hole alignment was a bit off so I could make corrections when drilling the 1/2 inch hole. The Wolfcraft drill guide stroke was a little short and didn’t the drill bit didn’t make it all the way through the deck post. After drilling this hole, I moved to the opposite side and completed the hole. Tip: The drill guide stop (blue knob by my left thumb) on the guide bar can be removed for a longer stroke:

Install 6x6 Deck Post - Drill Bolt Holes with Wolfcraft Drill Guide
Install 6×6 Deck Post – Drill Bolt Holes with Wolfcraft Drill Guide

Success! An accurate hole drilled through the post to the other side of the Simpson Strong-Tie standoff post base!

Simpson Strong-Tie Standoff Post Base - Drill Pilot Holes in Deck Post for Bolts
Simpson Strong-Tie Standoff Post Base – Drill Pilot Holes in Deck Post for Bolts

After drilling the 3/8 inch pilot holes through the deck post, I enlarged the holes with a twist bit by drilling from opposite sides of the post. Not sure why I didn’t think to use my 12 inch long twist bit here:

Through Holes for Bolts Drilled in 6x6 Deck Post
Through Holes for Bolts Drilled in 6×6 Deck Post

Pipe cleaners were used to swab a generous amount of Copper-Green Brown Wood Preservative (10% copper naphthenate) inside the drill holes as required by the deck building code:

Treat Deck Post Bolt Holes with Copper Naphthenate Wood Preservative
Treat Deck Post Bolt Holes with Copper Naphthenate Wood Preservative

I used about 1.5 gallons of Copper-Green Brown while rebuilding the deck.

Bolt the 6×6 Deck Post to the Simpson Strong-Tie Standoff Post Base

The deck post must be fastened with 1/2 inch bolts with washers and nuts to comply with the Georgia Amendments Prescriptive Deck Details based on the 2012 International Residential Code. The first galvanized bolt is being tightened:

Fasten 6x6 Deck Post to Simpson Strong-Tie Standoff Post Base with 8 inch Bolts
Fasten 6×6 Deck Post to Simpson Strong-Tie Standoff Post Base with 8 inch Bolts

The two 1/2 inch by 8 inch long galvanized bolts with washers installed. Recall the bottom end of the post is a bit darker than the redwood stain toner because I had brushed on a coat of the Copper-Green Brown wood preservative before mounting the post. I’ll leave the SD #10 screws in the bracket because removing the screws would leave holes:

6x6 Deck Post Fastened with Bolts to Simpson Strong-Tie Standoff Post Base PBS66HDG
6×6 Deck Post Fastened with Bolts to Simpson Strong-Tie Standoff Post Base PBS66HDG

I installed a 2nd nut on the bolts to serve as a lock nut. The 2nd nut is optional but will prevent the nuts from loosening as the pressure treated post dries:

6x6 Deck Post Bolted to Simpson Strong-Tie Standoff Post Base PBS66HDG
6×6 Deck Post Bolted to Simpson Strong-Tie Standoff Post Base PBS66HDG

Side view of the bolted deck post:

Simpson Strong-Tie Standoff Post Base PBS66HDG with Bolts
Simpson Strong-Tie Standoff Post Base PBS66HDG with Bolts

In the next updates, I’ll install the lateral support 2×6 knee braces, rebuild the deck rail and replace the improper installed deck boards.

Most people will want to install the beam-post knee braces next. I choose to rebuild the deck railing first because it was unsafe after removing several 4×4 guard posts.

This project is continued in How to Build a Code Compliant Deck Railing.

Thanks for reading,

Bob Jackson

how to install a 6x6 deck postsagging wood deck repairSimpson Strong-Tie PBS66HDG Standoff Post BaseWolfcraft Drill Guide Attachment
Bob Jackson
Bob Jackson
Technology product manager by day and a prolific handyman in the evenings and over the weekends. Bob was the founder of the original Handyman How To website and that tradition continues on this site with excellent new handyman content into the future.
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