|Forum topic by camps764||posted 10-26-2013 12:05 PM||1497 views||1 time favorited||11 replies|
10-26-2013 12:05 PM
I recently bought a used Powermatic 50 jointer. All three knives were shot. After reading online, I tried to sharpen the knives in place – no luck. So I built a small sharpening jig that I found on LJ’s. The jig is sweet, and would work really well, but the last owner, (maybe the owner before that) tried to regrind two of the knives and ruined them.
I ordered a new set – no big deal.
After reading the zillion and a half articles online about setting and replacing jointer knives I’m a little intimidated on the process. This is definitely a case of information overload. Some say they need to be exactly the same height as the outfeed table. Some recommend a few thousands proud of the outfeed table. Some reference the distance between the bevel and the cutter head. All agree that precision is absolutely critical to a functioning machine.
Here’s how I understand/plan to approach it:
1. I set the infeed table to the zero position – and made sure I got any sag out using a nice straight edge. I now have less then .0015 clearance at any point on the straight edge across the length of the tables – per the manufacturer’s instructions
2. Find top dead center on the cutter head using a dial indicator on a magnetic stand. The Garage Woodworks guy (thanks!) has a video showing this. According the video I put the magnetic base on the infeed table and locate top dead center on the portion of the cutter head that does not have a knife slot. Top dead center is the highest point in the arc of the cutter head.
3. Mark Top Dead Center on the fence as a reference point.
Here’s where I get fuzzy on the process.
4. Insert new blade so that it rests on the jack screws and tighten the gib screws very lightly.
5. Place the magnetic blade lifters (small jigs I made using magnets and pieces of flat steel) on the outfeed table. Position the cutter head so the blade is on the Top Dead Center mark on the fence and move the magnetic jig to the blade so that it lifts it up, even with the outfeed table.
6. Tighten down gib screws.
Move on to the next one.
So, my question for the wise masses on LJ’s: Does this sound like a reasonable process? Is it accurate enough? Am I missing something? Is there something that would simplify the process?
Thanks in advance folks!