I've refurbished/used/flipped both The PM15 and Jet JWP 15HO.
I'd choose the PM if price is near same.
Both will mill wood the same.
The differences are relatively minor, here are the ones I remember:
- Jet weighs less, due partial cabinet.
- Jet feed roller tables are single roller, PM has 3 rollers. Both use same easily damaged stamped metal roller frame.
- Some of the Jet 15" models had extendable 2" casters inside the stamped leg corners. The are wobbly, but OK for short move in shop on perfect smooth floors; but if tool is moved often you want a mobile base. Had to remove them as they were cheap stamped metal rusted beyond repair.
- The Jet 4 leg post's and top heavy cast iron make it hard to scoot around the floor, so you want a mobile base if need to move it. Will want to use a base plate on mobile base and attach the legs to base, or the the metal on metal combination can vibrate with heavy cut milling. This is simply due less mass down low.
- Some of the PM15 models had internal (2) fixed single direction castors, and (2) swivel inside the cabinet. They are practically useless due small ~1.5" size, and have to lock them down one corner at a time with bolt against the wheel from outside. They rust easily if exposed to moisture. Don't plan on using them unless your floor is as smooth as baby's butt. Nice idea, poor execution.
- PM15 uses a name brand US motor (Baldor) made in Taiwan, while the Jet uses a top rated Taiwan motor mfg. The look same, perform same and use the same motor bearings.
- PM15 uses longer belts, and is slightly more difficult to adjust for perfect tension to avoid belt slap on start up. I prefer to set the belt tension on loose side, as excess tension accelerates wear on the outer side cutter head hearing.
- The are both a PITA to color match. PM only sells the 2000+ metallic mustard spray paint, and Jet only sells the off white spray paint. If the PM machine is old school mustard, or gold; no of shelf paint matches. Same for the early Blue-Green-Grey from Jet.
There was a lot of commonality between spare parts, but they appeared to be mfg by different factories. The tell signs for me were the minor difference in slow/fast feed speeds; which also means different gear ratios and chain lengths on feed rollers. The gear box used same gasket, bearings, and seals. Both machines are clones of the Delta 15" planer, likely using same licensed drawings in the beginning. Which is why the castings, gear boxes, cutter head, and all expensive stuff to change is same.
Did not own these machines at same time, so subtle differences may exist I didn't notice as they didn't need fix up. There can be a difference tooth TPI in the helical drive gear on the end of cutter head, hiding in the gear box.
With inflation these 15" four post planers are very expensive now. Used prices are wildly variable. The PM was not that much expensive than PM when new. So don't get sucked into paying a high PM premium. Straight blade machine of those vintage have sold recently in my area and were less than $1000. Three years ago, I paid no more than $300 for rusted mess needed refurbished. Now folks want $500-$600 for same junk.
On both machines pay attention the bronze feed roller bushings, and oil leaks from gear box. These planers are hard to kill, and will run even when poorly maintained, or with worn out bushings. Have had to replace the bronze bushings on every machine I have touched, due excess wear and lack of regular oiling.
Another possible problem is the feed change lever. It is very easy to bend, and it becomes hard to change. A bent shaft will damage the oil ring seal, and/or damage the cast iron; needing a new gear box cover. Used a grizzly cover on PM15, so it was reparable, but not cheap with matching paint.
These planers are relatively quiet, unless milling wood. If you hear any growling, and gear box is full of oil; likely need new cutter head outer bearing (belt side). The outer cutter head bearing needs replacing every 10-15 years IME. You should use new bearings if you add a segmented cutter head, so this is not a concern unless you want to delay segmented head installation.
Best Luck.
