Monday, February 18, 2013

New Plane of Reality (III)

Well, today I was able to talk to a guy named Norbert in Kaslo, B.C. who runs tersaknives.com. He's Swiss and definitely knows his stuff. I told him what I had done and as I feared, the cutterhead will have to come out. It was a bit of a mix of good and bad news actually. Removing the gib plates from the head means that they would need to be sent back to the factory (ie., SCM) or to Tersa in Switzerland, to be put back on and be properly rebalanced. However, he said I had taken a reasonable step given the rust on the cutterhead and the sticky operation of the floating wedges. He said that anytime you buy a used machine that has been sitting for a while, like the one I bought, then it is wise to at least budget for a new Tersa head. The Tersa head needs to function flawlessly, and if there is any question about whether those floating bars will smoothly slide up and lock the knives in place, it is wiser to err on the side of caution and install a new head. Imagine the damage if one of the bars didn't lock the knife properly and then you fed wood into it - that could cause all sorts of expensive carnage. So, it looks like I'll may be getting a new Tersa cutterhead, and it will possibly be one of the newer types that does not have the bolt-on gib plates.

I spent a few hours today working on the machine, trying to remove the cutterhead. The head rides in a pair of NSK 6208DU bearings, which are 80mmx40mmx18mm. These bearings are fixed laterally in the carrier by a pair of large spring clips. Finding a tool to remove these large spring clips took two trips, out to four different stores, and eventually I picked up a pair of long neck bent-tip needlenose pliers that did the job. Finding quality industrial tools in my area is problematic and I hate not having the right tool for the job. Removing those clips allowed me to move the head laterally side to side, however I now need to remove the pulley on the end of the arbor and I am unsure whether the Allen head screw which holds the pulley on comes off clockwise or anti-clockwise. I'm suspecting clockwise, however I'll check with SCM first before heaving on it.

I will also talk to a few other technician about the head and see if there might be other opinions on the matter. I have learned from Edward Papa at Simantech, Inc. that SCM does not make the Tersa head-  it was actually another Italian company called MBM. MBM makes all of the Tersa 'Monoblock' style heads for the Italian machines, just as Martin makes the Tersa heads from the German machinery market. So, I've sent MBM an email to see what they say, and will talk to SCM USA tomorrow. In another day or two I should have a good idea as to which course of action to take.

Meanwhile, I've moved my planer over to sit next to the Hitachi resaw, and I think it will work well in this location:


The home of the green monsters, the new Fenway Park perhaps.

Another view:


I should be able to tuck them in a little tighter, which will entail moving the down-pipe for dust collection back a foot or two. I've also shifted the bandsaw to the side about a foot and brought it forward slightly.

All for now - thanks for visiting! On to post 4

6 comments:

  1. Have you looked into a byrd shelix cutterhead as a made in the USA option?
    an advantage when working with high figured woods, birdseye, curly etc.

    ReplyDelete
    Replies
    1. Thanks for your comment Joe.

      That thought has crossed my mind, and I do have a Shelix head on my shaper, however I find Tersa heads to give a very nice finish and see no particular reason to change to Shelix, though it might be a cheaper way to go than Tersa. I am trying to weigh all the options. My inclination is to go with something made by/for SCM as I can be sure it will fit without any issues and work properly. Thanks for the food for thought!

      ~C

      Delete
  2. I looked at teh Bryd site and they do list a cutterhead for your machine (24") 3500.00. i have a 15 jet planer that I spent quite a while sharpening the original blades for. By hand on a makita wheel with thier planer blade jig. Put them in the plane rwhen done and started to plane some curly maple boards, by the time I had done about 50 feet their was some "lines' left on the boards from the blades already having some small chips or divits in them. also I had to wet the boards with alcohol to keep the tearout to a minimum. Thats it I got on the phone and purchased the byrd head and extra cutters. Now i do not think about grain direction (well sometimes I try to) I just put in theboard and walk around to th eother side to take it out. and it is 100 times quiter... what a difference. money well spent. Bolted right in and byrd even supplied new bearings pressed on the head.

    ReplyDelete
  3. Joe,

    thanks for sharing your experience, much appreciated.

    ~C

    ReplyDelete
  4. Joe, you can not compare a 3" head with a 5" head. The finish is worlds apart. A 5" tersa head with fresh knives will handles some of the gnarliest grain. It's all about the sharpness and the approach of the cutter. If I was doing long runs of commercial lumber I might consider helical such as they use in 5 head moulders mostly because you can cheaply repair a nick. But for fine surfacing in a small production shop tersa is hard to beat for finish, cost effectiveness and efficiency.

    Chris, I do not think your head is ruined. The fixed potion of the gib you removed should just go back in it's original seat. I would guess that the head is cnc turned and slotted. As long as all the parts go back in their respective spots and not mixed up amongst themselves. It would seem that fixed portion was installed then the whole head turned again to flush the ends. The knives will not jump out of the head, otherwise there would always be a slight risk of it when starting up. If you remove the head I believe there is a big c-clip on the ends that will let you remove the wedging gib to clean it. Easier on a planer as the jointers bearing is squeezed in it's housing and needs to be tapped out. Usually having to replace the bearing to be sure it wasn't damaged in the process.
    If you have not removed the head yet I would try cleaner and a piece of shim stock or a guiter string to clean the area between the wedge and the head. You already have the fixed portion of the gib out to clean any way. But I have cleaned it in place with a brass brush or such. Also I use the edge of the knife to clean the way when I flip them by sliding them in an out a bit scraping off any pitch or such. Mine sat for a year, sounded like yours. I cleaned it up it functions as intended. It's the draw back to the system but they are not so fussy.

    ReplyDelete
    Replies
    1. Correy,

      thanks for the input. I agree with you in regards to the cut quality of Tersa.

      You'll see what route I took in the 4th post in this series, posted today.

      ~C

      Delete

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