|Forum topic by Jeff_in_LSMO||posted 03-12-2014 03:37 PM||643 views||0 times favorited||2 replies|
03-12-2014 03:37 PM
I have a hybrid table saw that I am happy with; however, I have never been able to fully align the table to the blade. It has been close, very close, but the table was bolt bound and I could never get it dead square. Then I recalled my days precision aligning electric motors, and a trick that we would employ.
Technically, only about three threads of any machined bolt are truly engaged when properly tensioned… or so I was taught in engineering school. If we were bolt bound we would prefer to open the holes in the feet; however, this wasn’t always possible, and in those instances we would turn down the shank or the unengaged threads to give us just a little more room.
For some reason I had forgotten this until last night. Not wanting to open the holes in my base, I pulled out the bolts, locked them into a vise, and used my Dremel to grind down the threads next to the bolt head. I did not grind into the shank, I took off just enough thread to give me a few more thousandths of movement. Put the bolts back in, and within minutes everything was dead square. Finally, after three years.
I just wanted to share this trick, because it can be very useful. If you are uncomfortable removing material from the bolt you can always find manufactured undercut bolts for precision alignments. They are expensive, but a safer route. See WORDS OF WARNING below.
WORDS OF WARNING: there is always a limit to how much material you can remove before you affect the strength of a bolt. I strongly recommend against using this technique on any safety item (especially in your car), unless you know what you are doing. Do not leave nicks or gouges, they can lead to failure. The preferred method for doing this is on a machining lathe where you can precisely control the amount of material removed. Do not use this technique on load bearing members unless you have performed the calc and you know exactly how much material you can remove safely.