Thread: Carbatec 15” thicknesser question

Sounds like hocus pocus to me, maybe he was trying to steer you to the other one as it's more expensive?

i ordered a 681 a few weeks ago as well
I think there doing this because of stock, it seems a larger percentage of people prefer the in feed table to be stationary like the 681 as opposed to the 381 which moves the in feed table

km

I have the CTJ381, and I reckon the quality of the cuts should be the same. The 680 has the much cheaper price and fixed tables which is what many people want. I do however think (only an opinion) that raising and lowering the motor/cutterhead will eventually put more strain on the winding mechanism because it is heavier than the tables. Changing blades will also be more of a challenge. You should also be careful if you intend to move it around. It is a little top heavy.
Regards
Les

I too was apprehensive about the weight being at the top, but the sales guy assured me that that wasn't an issue. He just kept going about the quality of the cut not being as good. His analogy was that the 680 was like an 80 grade finish compared to a 250 grit finish on the 381, as well as less snipe on the 381.

I didn't see how any of that could be possible as once everything is locked up and in place the mechanisms are the same.

Maybe he has drum sanders confused with thickness planers!

I have the 680 and all that sounds like a load of codswallop to me!

I achieve a very good finish off the 680, good enough to only need hand sanding before finishing.

Sounds to me he is either trying to "upsell" or knows there won't be any stock and wants to sell something there is stock of.

You have already pointed out one of the strong points of the 680, fixed table, so easy to arrange in/outfeed support without needing to adjust them.

The built in mobile base is also very good and the whole thing is very stable as you move it, mine lives out of the way until I use it.

The difference between fixed infeed table V fixed top mounted cutter & motor was explained to me thus;
note this is not from my own experence only the words of a professional woodworker.
When both machines have nice new sharp blades they both cut exellent & identical.
However the differences appear after the blades get a little worn.
It all comes down to the small amount of slop or give that is always in the worm gear that controls the cutting height in both machines.
In a machine with an adjustable infeed table gravity & the force of the cutting action push against the worm gear taking out any slop & therefore any chance of movement during the cutting action.
However in a machine with a fixed infeed table the cutter head is the component that moves. Gravity & the weight of the cutter/ motor naturally pull down on the worm gear leaving the small amount of slop in the worm gear & therefore a small amount of movement 'possible' in the upward direction. It would be possible, with worn blades, for the cutter head to 'chatter' over the timber due to the small slop in the worm gears.
To sum it up into something that hopefully makes sence, a moving infeed table will always press hard down on the worm gear leaving no possible chance for any movement EVER. The only movement available to the slop in the worm gear is up & gravity plus the cutting action stop that completly because the cutting head is fixed & therefore can never move up.
But in a machine with a fixed infeed table once again any possible slop movement is once again up but this time the cutter is the part that moves & 'can' be pushed up dependant on the smount of slop.
Provied the blades are always sharp this chatter would probably never happen however how many of us always keep their blades it tip top condition? Keeping the locking mechanism firmly engaged when cutting would probably stop most of this possible chatter but in a machine with a moving infeed table that chatter just isn't possible ever.

Hope this makes some kind of sence.

So, explain to me how a heavy cast iron table which has been adjusted a certain distance away from the cutter head and then locked in place, can "push" against the cutting head?

Well i figure that theres always a little bit of slop in worm gears & theres a trully massive amount of energy pushed into the blades & cutters & the locking mechanism i beleive is only on 1 post so i guess that the potential is there.

To be honest i myself think that its 1 of those 'in theory' things that only has a chance of appearing in the real world after some good years of use.

Rattrap, the way you have explained it makes alot of sense in relation to the push and pull aspect. I hadn't thought about it that way.

However if the head is locked, its locked and shouldn't move. But then again shouldn't doesn't mean it wont.

There could be some very small torsional play in the top assembly as I don't think all 4 posts lock, but that would be very small as the posts are rather thick and the sleeves are a decent length.

If only myhtbusters did a special on wood working, they could get thier high speed camera onto it.

Originally Posted by Rattrap

Well i figure that theres always a little bit of slop in worm gears & theres a trully massive amount of energy pushed into the blades & cutters & the locking mechanism i beleive is only on 1 post so i guess that the potential is there.

To be honest i myself think that its 1 of those 'in theory' things that only has a chance of appearing in the real world after some good years of use.

The locking system is on 2 diagonally opposed posts. In practice I don't even lock the head until the final cut, and I have never seen any evidence of movement in the head, or any snipe, which is usually caused by things other than the head anyway.

Let me say as a very satisfied user of the 680 that I have never had cause to regret my purchase, if I had reservations I would express them.
If the thing got knocked off tomorrow (heaven forbid) I would go out and buy another exactly like it.

I have put 3m 100x100 cypress posts through it finishing up with a perfect finish ready for painting (veranda posts, bought rough sawn).
On a job like that you are very appreciative of a fixed table let me tell you, if the table moved you would know about it.
I have also done small stuff down to 6 or 8mm in radiata, meranti, blackwood, red gum, you name it.

Please don't miss understand me, i'm certainly not dissing the 681or any other fixed infeed units, mearly trying to present a possible explanation for the salesmans statement. I haven't ever read of this actually happening to anybody with the 681.

I think that km,s statement is more likely to be closer to the truth. lol

Originally Posted by kmthor

I think there doing this because of stock, it seems a larger percentage of people prefer the in feed table to be stationary like the 681 as opposed to the 381 which moves the in feed table

km

all industrial/professional thicknessers have fixed cutter heads with rise and fall table. I have a 381.

see Ratraps reply...nuff said.

I went for the CTJ-381 due to ease of workflow. You can put the timber that needs thicknessing on the top of the rollers, stuff that needs going through sits on the right and stuff that has been through goes on the left and vice versa. With two people one feeding the machine and another grabbing it from the back it is very easy to process a large amount of timber.

Also very handy to put a sheet of mdf on the top and you have another surface for putting stuff.