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Planer blades sharp? PM 225

Started by tacks Y, March 04, 2021, 08:29:49 AM

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tacks Y

What degree are planer blades when new and resharpened? I have a new to me 60s PM225 now with grinder and hone. It seems to pull the grain more than other planers I have had. I did grind and now it is about a 42.3 degree and thinking to much? The grinder is one from a gold machine not the old green so thinking wheel is set different? I did joint blades and it helped some along with slower feed rate. Any advice?

Don P

Typically 30°, you can run steeper in softwood but it lifts more grain. If it is tearing too much at 30 you can sharpen the face back a little to make more of a scraping angle but it eats more power and can cause trouble sharpening later if you want to go back.

tacks Y

Quote from: Don P on March 04, 2021, 08:34:15 PM
Typically 30°, you can run steeper in softwood but it lifts more grain. If it is tearing too much at 30 you can sharpen the face back a little to make more of a scraping angle but it eats more power and can cause trouble sharpening later if you want to go back.
Problem is with the sharpener on the planer I see no way to get to 30 degrees. I more worn wheel may get me some but not that much??

Tom King

Interesting question about whether the gold grinder is different than the green ones.  I forget exactly how they're mounted, but wondering if you can drill, and tap some new mounting holes.

tacks Y

No chance to change mount, the wheel is mounted in the casting and dove tails to planer.

I had jointed the blades to see if that made a difference, seemed better but no longer felt sharp. So my idea was to rotate the index ring a little to change grind.  Seems better now but hard to tell as I slowed down the feed and taking lighter cuts.It is sharp now with no jointing. Maybe a new spiral head in the future? This is a direct drive but if I change heads will go belts with motor on rear under table. I had a 16" PM and changed motor location, not sure why factory was not smart enough to mount there in the first place. 

clay3

It sounds like you are sharpening the knives with the grinder. First  step is to joint the knives till all are jointed evenly, then use the grinder to remove excessive joint. The grinder does not sharpen the knife, it only removes the heel of the excessive joint. the jointer does the sharpening. Maybe this explains why you cannot get the angle you are looking for from the grinder.

tacks Y

Quote from: clay3 on March 05, 2021, 12:55:26 PM
It sounds like you are sharpening the knives with the grinder. First  step is to joint the knives till all are jointed evenly, then use the grinder to remove excessive joint. The grinder does not sharpen the knife, it only removes the heel of the excessive joint. the jointer does the sharpening. Maybe this explains why you cannot get the angle you are looking for from the grinder.
That is how I started joint then grind per manual. Left a small jointed area, less than .030" which they say is max. Just enough to see. Blades don't feel sharp after jointing. I have read some manuals say do this way others say grind then joint. Are you running this set up?

clay3

I always joint then grind, and normally every other sharpening a very light pass with the jointer is all. I don't have a manual the previous owner explained this to me, I do have the quiet cut but I don't see that would be any different. 

Tom King

I was talking about moving the whole rig a little farther back on the top of the planer, but like I said, I don't remember how it's mounted.  Wondering if the indexing of the head was different on gold, and green machines.

tacks Y

When I started this I had a new wheel that came with it 4 1/2" so on it went. That makes for a longer cut, the old one was around 4" after moving the index a touch I like it better and the smaller wheel is back on.  Will be running today to see how it goes. I have had some hickory, maple and cherry tear, my old planer did also some. A first on the cherry but it had an odd grain. Will see today, my PM jointer w/sprial head does great.

woodworker9

Your problem is 42.3°.  It should be 25° or 30° max.  The grinder bar for a Gold machine is in a different place than on the pea green and emerald green machine era's.  As you surmised, that is throwing off your angle.  Altering your indexing may help some, but probably won't make up that much of a difference.  Scrapers are ground at 45°.
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tacks Y

Thanks 9, Just not sure where to find the right grinder. It has the pea green bar, but came with a gold grinder. Thinking of tearing down the motor (direct drive ) and changing main bearings. So I will have time to monkey with the grinder, may just make a new one. I have wheels on bars from a Northfield, the dove tail where the motor mounts may take some thinking.

 I priced new knives and they are around 40 degrees also.

tacks Y

Quote from: woodworker9 on March 29, 2021, 12:18:28 AM
Your problem is 42.3°.  It should be 25° or 30° max.  The grinder bar for a Gold machine is in a different place than on the pea green and emerald green machine era's.  As you surmised, that is throwing off your angle.  Altering your indexing may help some, but probably won't make up that much of a difference.  Scrapers are ground at 45°.


After looking at pictures of the pea green grinders, the wheel appears to be in the same location. I need some one to lay the grinder on the dove tail on a bench or table and measure how far the wheel is up off a table.

clay3

My wheel is roughly worn and measures 3 11/16 dia. laying on the tablesaw , a 9/64 allen wrench will slide under it really snug. I have two grinders, not sure which one this is 180 or 225, both are green I'll look for the other one and measure it  too.

tacks Y

Quote from: clay3 on March 30, 2021, 02:10:12 PM
My wheel is roughly worn and measures 3 11/16 dia. laying on the tablesaw , a 9/64 allen wrench will slide under it really snug. I have two grinders, not sure which one this is 180 or 225, both are green I'll look for the other one and measure it  too.


THANKS, That is what I wanted to know. My wheel is at 3 3/4 dia and a 7/64 allen just fits. So the wheel is on the same plane. Mine if measuring off the dove tail to the center of the wheel is 3 15/16. Thinking this is short for a 225 maybe from a smaller planer because going from the jointer to grinder I have to run down a ways.

clay3

If  you can look at my gallery I put pictures of both grinders side by side, the 225 is much larger. The 225 has a 4 1/2'' wheel and flat on a table is about 3/32'' below the table. From dovetail to wheel center is 4 3/8'' (smaller) and 4 5/8'' (larger). The jointers are the same but the stone on the 225 sticks out 
3/8'' further than the 180. 

tacks Y

Quote from: clay3 on March 31, 2021, 11:53:35 AM
If  you can look at my gallery I put pictures of both grinders side by side, the 225 is much larger. The 225 has a 4 1/2'' wheel and flat on a table is about 3/32'' below the table. From dovetail to wheel center is 4 3/8'' (smaller) and 4 5/8'' (larger). The jointers are the same but the stone on the 225 sticks out
3/8'' further than the 180.


Thanks, This is the information I was looking for. Maybe next move is making a grinder and match your 225 specs.

kantuckid

FWIW, there a guy in Bonita Springs, FL easily found under Reardon's Machinery who has been a PM rebuilder for many years. I found him to be helpful and a great source for PM information. 
Kan=Kansas;tuck=Kentucky;kid=what I'm not

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