Thread: Self Setting Knives for Chinese Jointers & Thicknessers

I haven't used them but they seem like they might be allright, and should work as they say, my caution would be that if your infeed and/or outfeed tables are misaligned with your cutter head things might not be so good...
Pete

I've emailed the company and got a reply. They are considering whether they can make a set for the ML-392 since its not available in the USA. They seem to make the knife holder for each specific machine. Apparently it's the 250mm length that is non standard for them.

I sure hope they can do it. Apart from the initial cost, the knives are dirt cheap and double edged so that both edges can be used before getting new ones. I think its $25 for a set of double edged knives (2 change cycles). Not to mention hours less of P.I.T.A fiddling!

BTW, its a valid point about the table/cutter block alignment. However I found it pretty easy to get the tables perfectly co-planar and aligned with the cutter block. The ML-392 has adjustments for fore and aft levels on both the infeed and outfeed tables (through a concentric bolt in each table) and side to side levels through the levelling bolts. I'm warming a bit more to this machine given its ability to be set up with precision.

You can pick up a pair of magnetic blade setting guides from Carba-Tec for under $100. Bought a set for work and they are excellent.

Originally Posted by elanjacobs

You can pick up a pair of magnetic blade setting guides from Carba-Tec for under $100. Bought a set for work and they are excellent.

I have a set of those guides and like a couple of others on this forum I found they were less useful than using bar magnets straddled across the outfeed and infeed tables (which have been aligned)

The problem with them is that each of the jigs give different readings and if there is a slight imperfection on the cutter block body, the readings will be further out of whack.

I am using a digital height gauge to firstly align the tables to the cutter block and each other, and then measure for consistency of knife height using the outfeed table as a reference point. I have used the bar magnets as described elsewhere as a starting point to gain consistent alignment.

Even when I have achieved perfect alignment in the fitst instance ( to within 1/1000th of an inch), tightening the bolts moves things a bit, even when being careful with the tightening procedure and sequence. I have managed to manoevre the blades over the last few thou into place and checking it with the gauge.

The results before doing this were close and if I took it slowly, the jointed timber would come out smooth. However it was not perfect if I cranked up the pace a bit compared to when the jointer was new. The whole process is time consuming and fiddly, and I am hoping that there may be an easier way to do this accurately and in a couple of minutes, as is the claim for the self-set system.

Originally Posted by TP1

I have a set of those guides and like a couple of others on this forum I found they were less useful than using bar magnets straddled across the outfeed and infeed tables (which have been aligned)

Well it was worth a try The blades in our jointer and thicknesser are spring loaded though, so that might be helping as well

I have a set of those magnetic blade setting jig thingo's as well, I found them to be a bit useless, fiddly and just not good enuff.

It takes me about half an hour to set my blades in a process that sounds similliar to TP1, basically I bring infeed up level with outfeed, checking with a straight edge, new blades in and nip up bolts, the cutter block has screws under the blades, I slowly turn these to bring the blades up to 2 squares that I sit across the gap (infeed to outfeed), I watch for the squares first little bit of movement, tighten everything up and good to go...

Felder do a quick knife replace system that does only take minutes to change..

Pete

The Carbatec alignment jigs set your blades relative to the cutterhead, which MAY not be exactly aligned to your outfeed table.

There is another design of jig with magnets on two arms - I forget the name - it sits flat on your outfeed table, and two magnets on the ends of the arms are supposed to lift the blade up to contact them. This at least aligns the blade to the outfeed table, but I've never been convinced that the magnets would be strong enough to lift the blade up at top dead centre, or hold it in position accurately as the bolts were tightened.

Like several others I just use the straightedge method, adjusting each side of the blade until it carries the straightedge forward the same amount (I use 3mm) as the blade is rotated. This aligns the blades to the outfeed table, and doesn't take long when you get used to it. I can do a 3 blade cutterhead (JET JPT-310) in about 20 mins.

The Felder Tersa cutterhead is great (no blade setting required) - provided someone else is paying for your disposable blades ! This thread caught my eye because I assumed someone had copied the Tersa design, but the design that TP1 has found is actually completely different.

Originally Posted by Mr Brush

The Carbatec alignment jigs set your blades relative to the cutterhead, which MAY not be exactly aligned to your outfeed table.

There is another design of jig with magnets on two arms - I forget the name - it sits flat on your outfeed table, and two magnets on the ends of the arms are supposed to lift the blade up to contact them. This at least aligns the blade to the outfeed table, but I've never been convinced that the magnets would be strong enough to lift the blade up at top dead centre, or hold it in position accurately as the bolts were tightened.

Like several others I just use the straightedge method, adjusting each side of the blade until it carries the straightedge forward the same amount (I use 3mm) as the blade is rotated. This aligns the blades to the outfeed table, and doesn't take long when you get used to it. I can do a 3 blade cutterhead (JET JPT-310) in about 20 mins.

The Felder Tersa cutterhead is great (no blade setting required) - provided someone else is paying for your disposable blades ! This thread caught my eye because I assumed someone had copied the Tersa design, but the design that TP1 has found is actually completely different.

The design reminds me of the way Makita position the blades in their power hand planer, they have a bracket that fixes to the blade (with the use of a simple jig) which is then set into a groove in the cutter block and then clamped up.

Originally Posted by elanjacobs

Well it was worth a try The blades in our jointer and thicknesser are spring loaded though, so that might be helping as well

I'm willing to give it another go if I have not been doing it right. Firstly, My jointer/thicknesser also has springs (which both jigs can only just hold down.)

I am confident about getting both tables perfectly parallel to the cutter block but it is getting both individual jigs at exactly the same height which is the problem. I zero them and wind them out as described in the instructions, but as we know, the slightest error on one or both sides causes real problems. It would be better for me if the jigs were fixed in position to the correct height for this particular machine.

Having said that, I noticed that the Axminster equivalent model to the ML-392, does supply a fixed jig with their machines. Doesn't help me though!

I have a jet 8" jointer that has springs under the blades, it has a fixed height blade setting jig, I find this to be a bit PITA for setting, for me I like the feel of being able to bring the blades up and sight the first sign of correct height, but with the spring system I find that if I nip the blades up then the springs don't have enuff push to overcome the nip and then I try and lift them, and then that's too far, so I push them down, bearing in mind I have a sharp edge I don't want to damage, which is now too low, and round and round we go, I then try with less nip, which is better as far as movement of blades and getting them upto and contacting the jig (correct height) but then tighten up screws and this tends to increase blade height, so too high again, also, this system doesn't take into account any table cutterblock misalignment, on the jet I only have rise and fall hieght adjusment. I might get this cutter block machined to fit some screws oneday maybe who knows......

In my 300mm wide machine adjusting screws under the blades works best for me, I can nip up blades, with 2 long handled allen keys in each screw, 2 squares (in my case) or
(2 pieces of machined flat steel, brass, al...(key steel)) sitting at each end of blade and across the gap, I rotate cutter block back and forth (within the tables gap) as I bring blades up, this gives me a visual indication (movement of squares) of the blade reaching the correct height, if one side reaches height before the other I stop on that side, back off screw and if too high knock blade down using a piece of soft end grain wood, as I know the blade is held with nip it will only go down as far as I backed off the screw, keep bringing other one up until touch, continue until both squares are just moving, I prefer the slightest amount of movement as with final tightening it will add a bit to the hieght.
This method doesn't require cutterblock to be aligned with tables.
It is important to start of with tables at same height tho otherwise it's all for naught, time spent here is worth it. It took me a while to get the system happening, simple things like 2 long tee handled allan keys, one in each so I don't have to swap from one screw to the other screw, I aim to remove those sorts of frustrations as much as possible.
Replacing 3 blades takes about 1/2 an hour, start to finish.

Hope all this is helping TP
Pete

Originally Posted by TP1

I'm willing to give it another go if I have not been doing it right. Firstly, My jointer/thicknesser also has springs (which both jigs can only just hold down.)

The jigs i bought are the orange CMT Utensili ones (eBay not carbatec) and they came with a set of shims to set the height. Maybe also have stronger magnets.

You could try taking the springs out and just letting the magnets hold the blade up (I'm assuming the carbatec ones have a magnet on the slidey-setting-thing)

If that doesnt work then ....

Originally Posted by elanjacobs

The jigs i bought are the orange CMT Utensili ones (eBay not carbatec)

Do you have a link to one on eBay or a picture of yours that you can upload?

Originally Posted by DJ's Timber

Do you have a link to one on eBay or a picture of yours that you can upload?

Link here: PLANER BLADE MAGNETIC SETTING DEVICE/JIG - eBay (item 140325958691 end time Mar-06-10 03:57:22 PST)

I've managed to get the knives reasonably well aligned. I first adjusted the tables to be perfectly co-planar, level with each other and parallel to the cutter-block.

I used a digital height vernier throughout the process which was also used to set the height of the knives. I didn't have a suitable dial gauge and I assumed that this would be OK.

I first lightly fastened the knives and manipulated the setting at each bolt point - as was demonstrated in Bob Vaughn's video (link below).This process took a while and I then checked the accuracy using the "move-the- stick" method and it is also showed that the knives were correctly installed. The thing I did differently this time was not to try to get it perfect when I first set the height. Tightening the bolts moves the knives so a bit of anticipation and manipulation was the only way that my skill set was able to get it done.

I have now passed several boards through the machine for jointing and thicknessing and all seems well. Upon close inspection, there are still some machine marks visible when you look closely- ever so slightly more than I remember when the machine was new. My mind may just be playing tricks because it all looks fine but in any event, setting jointer knives is not my favourite pastime.

In case anyone hasn't seen the link to the video I mentioned here it is:
Jointer Knife Setting with Bob Vaughan