December 31, 2015

15" Planer Cutterhead Upgrade - Challenges

The bed project has been largely on hold for the last year as other priorities have continued to pop up. One of the things that has really slowed progress on just about every project has been dealing with tearout from the planer. While this challenge is what initially pushed me down the slippery slope into using hand tools it also means that much of my limited shop time is spent hand planing, scraping, and sanding out areas where the grain tore out from the planer. On top of that my planer knives were getting dull and needed to be swapped out and that is another few hours of shop time wasted. Those factors, along with Grizzly's Christmas sale on the Byrd Shelix spiral carbide heads, were enough to push me to finally pull the trigger on the upgrade. Based on recommendations from the WoodNet community I checked in with Holbren and they confirmed the Shelix head should fit my generic Taiwanese planer (a clone of the Grizzly G1021 or Delta DC-380 shown below) and they agreed to match Grizzly's price so I placed the order with them.

I received the cutterheard and and eventually headed out to the shop to start the install following the instructions provided by Byrd. Disassembly went smoothly at first and the head and gearbox came out of the planer without much issue. Then things went down hill. I removed the bolts holding the gear box together but it did not separate nicely as the instructions implied. I bought this planer used and the gear selector that is supposed to allow you to change speeds was "stuck" the entire time I owned it. I never saw a need to change speeds anyway so this didn't bother me but the fact that the rod (#131 below) was seized in the cover casting made it difficult to pull apart and resulted in it breaking at the point where it is bolted to the yoke (#129) as the gear case was forced apart. A bit of creative work with a 3-jaw puller removed gear #120 allowing access to the helical gear #112. The helical gear was also stuck on shaft and was a challenge to remove. After removing bolt #113 we ended up pounding the cutter head shaft out of the gear and through the bearing in the rear case.

At this point it seemed like we were out of the woods right up until I checked the fit of the helical gear to the mating feature on the new cutterhead and found the spline on the head wasn't even close to fitting the slot in the gear. Ugh.

I got in touch with contacts from both Holbren and Byrd and they confirmed that it wasn't as simple as receiving the wrong version head (they commented they are all the same) but that this planer seems to be different than everything they've come across in the past so they asked if I could take some measurements for comparison.

The slot in the helical gear measured out at about ~0.325" while the spline on the cutterhead measured ~0.400" exactly as spec'd by Byrd. This confirmed that the head was good but my planer was in fact different than 99% of the similar models out there.

After providing these measurements Garry from Byrd suggested that the easiest path forward would be to mill out the slot in the helical gear to match the cutterhead or if that wasn't something I could get done easily he offered to send me one of the standard gears with the hope that the only difference was the slot width. The offer was much appreciated but since I had to replace the gear shift handle anyway I ended up ordering a replacement gear through grizzly along with the other parts. If that doesn't fit then I'll have to fall back to milling out the slot in the original gear.

While I was reviewing the parts diagram (above) to find the right replacement parts I also noticed that my gearbox was clearly setup differently and after some head scratching it appears it only has gears to support a single speed and that the gear change handle was likely "seized" on purpose by bending the handle shaft to prevent someone from trying to shift into the non-existent 2nd speed. I've heard of planers like this with "single speed" gear boxes but I'd be surprised if this sort of hack was the typical production approach to dealing with the gear selector handle. At this point I'm guessing I will likely end up taking a similar approach once I get it put back together but I'll have to play around with the gearbox once I get the replacement parts to see if any better options are pop out. It was also interesting to note that my planer is missing the entire chain tensioner assembly (#106 etc. in the diagram below) nor the mounting features in the casting to support it.

Once I get parts and get this oddball back up and running I'll report back on how things worked out. Hopefully this info is useful to someone else out there that might have an odd-ball 15" 4 post planer like this one with a single speed gearbox, no chain tensioner, and non-standard cutterhead drive spline. It turns out these clones are not all the same after all...


  1. Hi Chris, I have a Grizzly G1021 that is the same as your machine. I was putting a Byrd cutterhead in as well. Since it was apart, i ordered the gears to make it a 2 speed and that has gone well. I do have the same issue with no tensioner or mounting holes to add it, did you end up doing anything to rig some sort of tensioner. My drive chain hangs low enough to actually touch the bottom sprocket when assembled. It did not seem to cause an issue when it was running before I noticed this, but now that I see it it is bothering me and I may remove on or two links in the chain to snug it up.


    1. Brian,

      I never did anything to address the lack of a tensioner. I posted this ordeal on the WoodNet forums (,All_Forums,&Words=&Searchpage=0&Limit=25&Main=7181886&Search=true&where=&Name=80243&daterange=&newerval=&newertype=&olderval=&oldertype=&bodyprev=#Post7181886) and a few others commented that their planers were also missing a tensioner and none of us had ever experienced issues because of that. When I mentioned the slack to a few engineers at work the general consensus was that when the planer was running the tension on the chain would tighten things up such that it would prevent any interference. Sure enough when I manually turned the drive pulley with the cover off you could see the chain tighten up.

      Glad to hear that you didn't have any issues adding in the gears for 2-speed operation. I think I will get by with the single speed but it is good to know that option should actually work later on if needed.

      Best of luck with the new cutterhead. I have been fairly pleased so far.


  2. I have a Delta DC 380 I'm restoring, 2 speed gear box. My chain is too loose how hard to shorten it???

  3. I have a Delta DC 380 I'm restoring, 2 speed gear box. My chain is too loose how hard to shorten it???

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