Sorry Tom
One more dumb question (I’m new to saddle hunting this year )
If you use 6 inch bolts are you only drilling 2 inches into the tree?
The Treehopper hand drill and cordless bit drills a hole roughly 2 5/8".
My old Woodpecker hand drill drills about 2". Side note: This 5/8" difference is why people believe the Woodpecker drilled faster. It didn't drill faster, it's just that the Treehopper drilled 5/8" deeper which takes more time/revolutions.
Here's a comparison of a 6" bolt to a high quality EZClimb step.
The screw-in actually has slightly less insertion into the tree than the bolt and the external comparison is roughly the same.
One thing that I will stress is that you do not want the threads protruding from the hole. The thread section of a bolt has the weakest shear strength and if threads are exposed, then you aren't utilizing the full strength of the bolt.
A properly sized hole gives support 360 degrees to the bolt throughout the threaded section. I'm not a big guy...I was climbing at about 200 pounds (total body weight, clothes, gear, etc) and I've never had a 6"x3/8" grade 8 bolt bend or break.
And keep in mind that there are variables involved. Thickness of bark is one very important detail. Angle of the hole is another detail. the greater the angle, the further out on the bolt that your weight will be distributed which causes greater leverage on the bolt.