Converting to a Spiral Cutterhead

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Forum topic by Randy T posted 06-04-2018 12:56 AM 856 views 0 times favorited 11 replies Add to Favorites Watch
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Randy T

38 posts in 607 days

06-04-2018 12:56 AM


I have a 20” General Planer with just the standard 3 straight blades. I am considering changing out to a spiral head.

My question is not around how much better the spiral head is, but how difficult a job is it to switch the heads?
Have any of you changed that cutterheads on larger planers like the one I have?
If so, how big a job is it?


-- Randy & Corinne, R&C Creations, British Columbia,

11 replies so far

View cabmaker's profile


1745 posts in 3411 days

#1 posted 06-04-2018 09:28 PM

last time i priced a spiral head for a twenty inch,,,,,it was 2,200.00

but that was for a us made delta with a near 6 inch diameter cutting head

View Peteybadboy's profile


1463 posts in 2551 days

#2 posted 06-04-2018 09:39 PM

I have changed the 3 blade out for the byrd shelix. You need real good instructions, and understanding of how to dismantle your machine. I would say not real hard, but you (or I needed) confidence. You tube and a mechanical friend helped me. Still we missed a screw and it cost me.

-- Petey

View msinc's profile


567 posts in 1105 days

#3 posted 06-05-2018 01:11 AM

Yeah, you gotta have some mechanical ability. Between that and youtube it can definitely be done. Even with plenty of mechanical ability and youtube you will still want to take your time and somehow label the parts you took off the machine. What I have seen happen repeatedly, and not just with a spiral cutter head but with many different operations on machines, the person doing the wrenching gets into some kind of a jam and forgets how something went back together. That’s generally when I get the call. Even if they would have just laid everything out one part at a time as it comes off on a big sheet of paper or cardboard so you can see what goes next would have probably solved it. Don’t rush and mark everything or set it in order…most of your problems are solved with that.

View BMichs75's profile


102 posts in 2260 days

#4 posted 06-05-2018 01:30 AM

I just recently (2ish months ago) changed the 3 blade cutter head in my PM 180 out with an 18in Byrd Shelix. Between youtube and and exploded diagram of the machine I got the job done. I definitely recommend having a large gear puller for pulling gears or housings off of gears. The job took me about 2 weekday evenings to complete and an extra day to get all the parts setup correctly again. I love the results. My planer cuts cleaner and much more quiet. Good luck

-- Brandon

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Randy T

38 posts in 607 days

#5 posted 06-05-2018 10:55 PM

Thanks guys.
If I decide to bite the bullet and go ahead with it, I will make sure to take your advise to heart. Especially about marking and laying out the parts. I think that have someone to help will also be something that I would have as well.
Thanks again.

-- Randy & Corinne, R&C Creations, British Columbia,

View TheFridge's profile


10859 posts in 2088 days

#6 posted 06-06-2018 12:04 AM

I use clear plastic cups or bags to keeps nuts and bolts with the parts. Just remember as your taking it apart to take pics of how things came apart. Most of the stuff is a no brainer but for the complicated assemblies it helps.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View darthford's profile


612 posts in 2526 days

#7 posted 06-06-2018 06:32 PM

I swapped a Byrd into a Grizzly 15” a few years ago, this required a hydraulic press. Instructions said tap out the shaft with a hammer that was no go. It went BANG when it let loose in the press. The rest of the swap was easy.

View Holbren's profile


23 posts in 1606 days

#8 posted 06-06-2018 10:57 PM

These instructions should work assuming you have a 4 post 20” machine.

View Randy T's profile

Randy T

38 posts in 607 days

#9 posted 06-06-2018 11:12 PM

Thanks for the suggestions, and the instructions. I have saved those in case I decide to go ahead with the switchover.
It is a money thing at this time.

-- Randy & Corinne, R&C Creations, British Columbia,

View CaptainKlutz's profile


2208 posts in 2096 days

#10 posted 06-07-2018 07:59 PM

The PM 4 post 20” planer are almost identical to common clone 15” versions (even using some of same parts). for another reference: Fine Woodworking web site has 2 part article on 15 inch conversion.

One note of caution for when you proceed: Have a helper handy.

Did a complete rebuild on 15” planer recently. The stock steel cutter head on 15” weighs 45+ lbs alone. Adding cast iron gear box full of gears attached to one end of cutter head via pressed on bearings makes for a heavy chunk of iron. Disassembly is easy as you have advantage provided by gravity. Reassembly is harder. One person can lift the head/gear-box assembly, but manipulation of 70+ lbs of rotating iron chunks attached by bearings into the machine is much easier with two people.

You might want to think about what else needs serviced while you have the cutter head and gear box assembly removed? Suggest need minimum of (1) oil seal, (2) bearings, and gasket to go along with any cutter head replacement on older machine.

There are typically 7 bearings and 2 oil seals in the planer gear box assembly, plus 1 bearing on end of cutter shaft. You can replace all of the bearings for less $10 each using high quality bearings. My total cost was <$90 for locally sourced USA made bearings, Taiwan made oil seals, and OEM gasket on total cutter head rebuild. If I was spending time to replace a $2000+ cutter head on a well used planer; would consider changing bearings, at minimum would change 2 cutter head shaft bearings as they turn high RPM. Gear box bearings do not see as much wear inside box full of oil turning in-feed/out-feed rollers slower, so they should be ok unless the planer has seen massive usage. Plan on replacing the cutter head oil seal to ensure no leaks with new head unless machine is near new (<$5 cost). The gear box gasket is supposed to be reusable rubber type, but if machine is more than 5-10 years old then suggest you order a new one before you start so you are not waiting for parts.

Based on what I read in WWW, appears most of us servicing 4 post planer heads end up doing disassembly one afternoon, then order parts needed, and then reassembly several days later. It is what I did.
IMHO – If you are mechanically inclined with proper tools and needed parts ready, can remove/rebuild/install cutter head in about 1/2 day. (assuming bearing replacement process goes smoothly) It is not complicated job; just involves bunch of steps, proper management of pieces removed (bags/trays with labels), and some patience.

Best luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View Randy T's profile

Randy T

38 posts in 607 days

#11 posted 06-08-2018 02:10 AM

Captain Klutz:
Wow, what a detailed response. Thanks.
I will be sure to have another set of hands available when it comes time to do the install.

-- Randy & Corinne, R&C Creations, British Columbia,

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