Sunday, February 17, 2013

New Plane of Reality (II)

Getting the planer off the pallet required a little head-scratching as I lack a forklift. In the past when taking machines off of pallets I've made use of pivoting the center of mass around, using lots of blocks and supports, Johnson bar, etc., and gradually maneuvering the machine down to the ground. This time, I decided upon a different approach, realizing that the machine had lifting hook points and could be hung from an overhead beam, which measures something like 12"x14". I used the pallet jack to get the machine up as high as I could, attached a couple of 1-ton ratchet straps, and gradually lowered the pallet jack until the straps took the weight, keeping an eye on the beam above:

The beam didn't make even a creak. A few minutes later I had the machine off the pallet and onto the pallet jack with a couple of blocks:

A few maneuvers later, the intermediate blocks were out and the machine was directly on the pallet jack and I pushed the behemoth over to the position I had in mind.

Trouble is, the position I had in mind, nestled next to the jointer, wasn't looking quite as good as I had hoped. The height of the SCM planer is just a bit higher than the Martin planer, and that means that a board coming out of the machine could potentially run into the jointer's fence support arm, and that's a meeting I would most certainly want to avoid with 10 hp doing the pushing. So, I could raise the jointer up another inch to clear, but I would rather not actually, as i like the working height as it is. Considering the tilt of the floor in that location (it's an old mill building with wonky wooden floors), I am guessing that by the time I have the planer level I might need to bring the jointer height up more like 1.5" or even 2". So, that's not looking quite so promising at all. The width of the planer also makes space around the adjacent router table a little tighter than ideal.

I'm thinking I might move the planer over to a spot next to the bandsaw, which would still be just a couple of steps away from the jointer outfeed, plus I do have a 6" dust collection pipe there which is the size I need for the planer. I've already cut the dust pipe at the jointer and places a 45˚ lateral in the line, but it isn't riveted and taped yet so it would be no big deal to put a clean run of pipe back in place. Also, the location next to the bandsaw would mean a decrease in EMT metal wiring conduit of about 25', plus attendant couplings and so far, and the associated 100' of wire (25'  each for 4 wires).

I think I just convinced myself to move the planer over by the bandsaw - this blogging can help me organize my thoughts at times!

I set to work on the planer wiring and fairly quickly determined where it had been modified so a to operate on 460v. I simply had to remove one wire and re-connect another wire, as well as reset some dials on the overload protectors. I'm not entirely sure about the exact settings on those dials, so I'll call SCM early in the coming week to see what they say.

Wiring sorted, I vacuumed the interior of the machine. There was dust in there - not too much though. I'm guessing some of it simply migrated in from other parts of the shop where it was located, as a planer generally produces chips, not dust.

Then I decided to clean the planer's cutterhead. I thought it was mostly dirty with pitch residue, however a scrub with turpentine did little to change the appearance and I was realizing, to my chagrin, that it was actually surface rust on the cutterhead. I got out some rust-dissolving spray chemical and started to scrub the cutterhead with that, using a 3M abrasive cloth. After a moment I realized the work would be a lot safer if I removed the knives. I got out the wooden block and tapped on the wedge bars, but I found them a bit sticky and not as easy to move as on the Martin, which after all is brand new. I got the bars loose on one knife and pulled the knife out, but it was also kind of stuck in there and didn't slide out as easily as I might like. Of the three remaining knives, one was about the same as the first and the other two were a bit easier to remove. I decided that it would be a good idea to clean in and around those floating lock bars as it is critical to the functioning of the Tersa system that the bars move be able to slide into position absolutely smoothly. The bars however cannot be extracted due to their shape. I saw that the knife on the head was fixed to a bar which was held in place with about a dozen metric cap screws, and I thought if I removed the bars that I could then pull out the rest of the knife-locking mechanism. The Allen-head cap screws were in pretty tight, but I managed to remove them pretty easily using an impact driver. I worked my way around the head, and on the second-to-last bolt, I had the bolt head snap off. Damn! So that was one problem to deal with, though I'm reasonably confident I can fix it.

The drag (besides the one snapped bolt) was that the bar I had 'freed' still would not come out, nor would it allow the wedge bars to come out, though all the parts were loose. A bunch of work for nothing perhaps. Grrr.

I returned to my scrubbing with the rust-removing chemical, and the last face on the head I got to was the one with 'SCM' and 'TERSA' engraved on the face, and some other writing I couldn't make out clearly. After a few minutes of cleaning, sure enough the writing came into clear view. It was starkly clear. It told me that it was 'verboten' to remove the fixing screws! Shit.

Intentions... well, the road to hell is paved with good ones it seems. I thought I was being careful and meticulous and making reasonable moves in an effort to have the planer head in good function. Now I am worried I have done something I shouldn't have and that leads me to feel less than brilliant.

I'm trying to think of why it would be against the 'Tersa law' to remove those screws. The cap screws in the cutterhead were put in with some sort of thread locking compound and maybe the warning about removing them concerns possible breakage of the bolts, or perhaps the company was worried that the bolts would get reinstalled and not torqued properly, or that the thread-locker wouldn't be renewed. You certainly wouldn't want that part to come loose while the head was spinning or carnage would result. The bolts hold down a bar which serves as the mounting for the Tersa knife. I gather that this is an older form of Tersa as the newer ones, including the one on my Martin, do not have this bar at all - the head is machined in one piece and only the floating wedge bars are placed in the head afterward.

I'm thinking that if any debris gets under that bar and then it was fixed down again, the precise tolerance of the knife position might be affected. In fact, my suspicion is that the precise positioning of that knife support bar is the reason you should never remove the bolts. If the bar is fastened back down and is off by a few thousandths each way with each knife, then potentially the perfect cutting circle is ruined or the knives wont be properly tensioned by the floating wedge bars when the head is spun up. Either way, cut quality would be impaired. I'm hoping my conclusion here is erroneous and all will be okay, but that sinking feeling is definitely present.

The thing is, given the stickiness of the knife removal, and the rust, I wonder if the functioning of the head would have been correct even if I'd left it entirely alone?

Of course, these kind of things invariably happen, Murphy's Law and all, when it is late on Friday or early on Saturday and there is no opportunity to contact technical support personnel until Monday - and this coming Monday is a holiday in the US. I'll have to sit tight for a while and stew on things.

I'm thinking that the 'best case' outcome here is that I have to remove the cutterhead from the planer, remove a spring clip and washer on the end of the cutterhead, which will hopefully allow the wedge bars and blade-support bar to be removed, then I can meticulously clean everything and reassemble, torquing to spec. and threadlocking it out to a fare thee well. Then I put the head back in the machine, and see how it planes. If it doesn't plane as it should, then the cutterhead comes out again, and well, likely I would then be looking at the 'worst case' scenario: I have ruined the cutterhead and will have to obtain a new one, which is an expensive proposition. Neither best nor worst case scenario is especially appetizing.

Yesterday was a great day, today - not so much. I really hope I haven't learned an expensive lesson here. I don't mind the lesson, it's the expense. We'll see what comes out of this. I researched the matter on the web but could find nothing helpful, so Monday (or Tuesday) should provide clarity when I talk to SCM.

All for now, over and out. On to post 3


  1. Hello
    Woodworking maschines are as much interesting as woodworking itself. My experience says that many of used maschines are out of right settings. Almost all. The newer the used maschine, the more troubles. Hard to say is it only a user fault or not but I have been forced to correct a lot of factory mistakes as well. I suggest You to check all main things like table hight,pressure bar hights, roller hights etc, before You let it into operation. There is no point to have expensive and capable maschine which is out of control.
    Question is where to get these datas ? Better machines have some sort of checklist in passport, where You can find factory and actual tolerances. Probably SCM people do have them as well.
    In this part of world we are a bit sceptical about italians and the quality of maschines what they are producing. But I think this SCM model is a good maschine as it is their flagship. In the first picture where side is open I can see variator transmission for feedeng rollers. Is it so ?
    Or has it frequency converter for feeding speed control?
    Best regards

    1. Hi Priit,

      thanks for the suggestion - I plan to go through the machine fairly carefully, though for the most part it looks to be in excellent condition.

      I understand your skepticism about Italian machines and generally agree. For the price though, this machine was a good deal and should serve me well. If it doesn't, then I'll save up for a Martin.

      The planer has variable pneumatic pressure control for the infeed and outfeed rollers. It also has variable speed, 5~20meters/minute.



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