What is a proper jointing technique?

[tibi]

Hello,

I purchased Felder Hammer A2-26 jointer/thicknesser in November 2023. I am overly happy with the machine, but I have some issues that I think have to do with my technique, not with the machine itself.

I would like to illustrate it with an example. I am now jointing oak boards for the tabletop for an adjustable office desk. When I was doing everything by hand, I just planed off the high spots and done. Now when I start to join a board, it self-creates any reference plane it deems fit and follows it along the whole process. It then takes much more material than I would, if I did it manually because the machine has no discretion.
Here is a recent example.

I have 50 mm thick, 150 - 200 mm wide oak boards, which are 1,5m long and have a bow in the middle.
I orient the board bow side down. I apply pressure only on the outfeed table (just safely behind the knife) as I was taught on youtube. I also experimented with applying pressure on the infeed table and on both infeed and outfeed table and by the sound of cutting it makes a difference.

When I am finished, the board is 30 mm thick on the front edge (which went to the jointer first) and 45 mm thick on the furthest edge. I would like it to be even, so I minimize the wasted material. Also jointing one face takes me around 20-30 minutes, which is ridiculous (with a 2 mm cutter setting). I would probably have done it faster by hand. What I might be doing wrong to even out material consumption and also how can I joint boards faster? In the manual, there is a warning that partially feeding material into the machine without making full front-to-back passes is prohibited.

Thank you for any suggestions.

 

[MikeK]

Depending on how much bow the board has, you might have to remove a lot of material from both sides before you have a flat board. I worked with some 35mm thick oak slabs that were better suited for a boat hull instead of a set of shelves and noticed the same issue you described. While the thickness was mostly uniform along the slab before I started, the difference became more pronounced after five or six passes through the planer. I attributed this to the end of the board being pushed up slightly by the cutter block as it passed over it because I was not applying any pressure and the weight of the board was insufficient to keep it in firm contact with the cutter head. Also, the combined length of the infeed and outfeed tables on my SCM FS30G P/T is 1.2 meters. Once the leading edge of the bowed material reaches the end of the outfeed table, it will drop off (no table extensions yet) and the slab is no longer supported by the top of the table.

When I started like you described, I stopped pushing the board through when the cutter block was no longer touching the board. I then lifted the board, flipped it around and fed the other end over the cutter block until it stopped removing any material. I repeated this until the knives were removing material and the board was mostly flat on that side, which also meant the slab was in contact with the surface of the outfeed table. The last pass over the cutter block was with the board orientated to minimize any tear out, which is rarely a problem with the Tersa knives. This was the only way I could maintain a uniform thickness at the ends of the board while planing it down.

Concerning the amount of material removed, I think removing 2mm at a time is a bit aggressive. I never take more than 1mm at a pass on the planer and creep up on the finished side or edge. Most of the time, the amount of material to be removed for the final pass is less than 1mm, so I would not like to be removing any extra material.

I never kept track of the time spent working on the P/T, but I know I didn't spend more than 20 minutes to run four 1.5-meter long cherry slabs through the planer and thicknesser to flatten two sides and one edge (I used the tracksaw to trim the second edge). I'm guessing, but the 2mm setting might be slowing you down much more than two passes at a 1mm setting.

 

[Yojevol]

I think you have misinterpreted the way to present a bowed board to the planer. The bow should point upwards such that ends are supported on the infeed table. Push the workpiece over the cutter but don't apply any downward pressure, just let gravity do the work. This will remove material from the leading and trailing ends. Take sufficient cuts until the bow is removed. This method will remove the minimum material to get it straight.
If the board is twisted you need to apply a downward pressure on one corner to keep it stable until flats are achieved on both ends. Another tip for a twisted board is to glue a temporary block to support a raised corner such that the cut is taken equally from diagonally opposite corners. If the twist is severe the board can be ripped into 2 and glue back together again after planing. This will halve the amount of wood wasted to achieve flatness.
Brian

 

[toolsntat]

What are the measurements at both sides of the ends?
Cheers, Andy

 

[Jacob]

Assuming a normal regular sort of bow and/or twist; bow (convex) side down works very well if you keep pressure on the board in the middle only, during the whole pass over a planer.
Ideally the result is that the last pass removes roughly equally amounts from the opposite ends, opposite sides too if twisted.
If you start with pressure at one end you remove more from that end than the other one. It's obvious really if you think about it.
PS or do it concave side down as @Yojevol describes above. I generally prefer convex side down and do it as a matter of course.

 

[niall Y]

The longer the board, and the larger the bow - the thinner the finished thickness will be. So keeping it as short as possible will help.

When surfacing the bowed board, reversing it at regular intervals should help even out the amount of stock planed from either end. You don't have to completely surface each board before switching to the thicknessing part of the process. That there are enough flat areas to bear on the bed is good enough. That final clean up of the surfaced side can be done when thicknessing

A careful examination of each board might show that the excessive bow in a single board is going to reduce the overall thickness of all the boards unless you replace it with a less bowed board. For this reason having just enough stock for the whole job is a false economy.

If you have particularly bowed and twisted boards, they can be fed through the thicknesser whilst supported on a known flat board with wedges and battens holding it in position.

 

[Hornbeam]

If the board is twisted. you will tend to take all the material off the low point on the trailing edge, whereas what you want is to take it fairly evenly from the low points on both ends (which are diagonally opposite)) If it is a really bad twist you can turn the board round but keep it concave side down an. d look at grain direction
Also be aware that as you have found you can end up with a board flat on on side but with very large thickness variation. Check you thickness so you dont end up trying to take too much when you progress on to thicknessing

 

[Cabinetman]

As said above- good advice. Hands in the right place at the right time can make a difference, I use both hands on the main length of the board with the forward hand fairly close to the leading edge, as the wood starts to be cut and it goes under the Bridge guard my leading hand keeps its downward pressure with the bit of the palm nearest the wrist, at the same time the fingers reach over the guard and start to press down on the wood as it emerges from under the guard, as more wood emerges from under the guard the rest of my hand goes over the guard. Then the forward and downwards pressure is spread over both hands on both tables, a similar thing happens as my rear hand approaches the guard. Now wouldn’t a video have been easier!
How to do this safely with a Pork Chop guard is anyone’s guess.
Ian

 

[Peter Sefton]

The issue could be down to a wide range of reasons, it may be the set up of the machine, your technique or a combination of both. If you used to be able to use your machine get get consistent cut on the front and back end of your board then I would say your blades are getting blunt or may just have one chip out of them, making the board ride up the out feed table.

The videos I made a few years ago cover these topics in detail using Felder machines as well as older other brands models with either traditional HSS blades, quick change M42 cutters and TC silent power spiral blocks, all have different characteristics.

The DVDs are also available as digital downloads.

https://woodworkersworkshop.co.uk/peter-sefton-ultimate-jointer-collection-set-of-2-dvds/

Hope you get the problem resolved, it should be so much quicker than ever planing by hand!

Cheers

Peter

 

[tibi]

Thank you all very much for your insights.

Finally, I found two issues. The first and the most obvious one was that the knives were already blunt (maybe after 6-8 hours of use in clean solid wood). As Felder has two-sided knives, I have just rotated them for a fresh edge (they have a self-setting cutter block). The second issue was that the knives were below the outfeed table level - they were set up this way from the factory. The ruler did not move at all when I rotated the cutter block manually. I have set them slightly above the outfeed table and now I can get the first face level in 5 - 6 passes with a 1 mm setting. It used to be 20 - 30 passes before or more. Maybe because knives were blunt and the wood was jumping above the cutter block instead of being cut.

During my jointing, the feedback from the machine was much better, so I was able to use all your advice to my best ability. I got mostly 40 mm out of 50 mm board for 1,5m length.

Thank you again.

 

[tibi]

I think you have misinterpreted the way to present a bowed board to the planer. The bow should point upwards such that ends are supported on the infeed table. Push the workpiece over the cutter but don't apply any downward pressure, just let gravity do the work. This will remove material from the leading and trailing ends. Take sufficient cuts until the bow is removed. This method will remove the minimum material to get it straight.
If the board is twisted you need to apply a downward pressure on one corner to keep it stable until flats are achieved on both ends. Another tip for a twisted board is to glue a temporary block to support a raised corner such that the cut is taken equally from diagonally opposite corners. If the twist is severe the board can be ripped into 2 and glue back together again after planing. This will halve the amount of wood wasted to achieve flatness.
Brian

This is how I originally did it. Bow was pointing upwards, so the concave side was done. Cutting - Gap - Cutting.

 

[Jacob]

Convex side down also works because the middle of an evenly bent/twisted board should be near parallel with the best face you can get. Pressure in the middle means that you extend this flat area with each pass and remove least possible material.
Not cutting -cutting- not cutting.
Concave side down is similar but pressure at each end can make it rock about a bit and is slightly less easy to control and more hit and miss.

 

[Inspector]

This is how I originally did it. Bow was pointing upwards, so the concave side was done. Cutting - Gap - Cutting.

I was taught by my Danish trained father to set the middle of the board down over the cutter head. Then cut the trailing end. Rotate and repeat. When close to flat, do the entire board. Basically Gap>>>Cutting. Rotate, Gap>>>Cutting. And finish Cutting>>>>>>>. I do the same if it is a 400mm or a 2 metre heavily bowed board. The main reason for doing it like this is, with severely bowed boards the tip isn't diving into the the cutter head before the tip touches the outfield table. While I can and have used Jabob's method I prefer the way my father taught me. In the end I doesn't really matter as long as you get a flat/straight board. There is always more than one way to get something done.

Pete

 

[Doug71]

Sometimes when dealing with bowed boards you can get one side nice and flat using the surfacer (jointer) only to find when you put it through the thicknesser it comes out bent again.

I think when surfacing it's best to keep flipping the board, alternating between taking a bit off the ends of the concave side and some out of the middle of the convex side until one side is as flat as you need. This helps keep the stress equal in the timber, plus it speeds up the thicknessing process, it always seems like time wasted if you are putting long boards through the thicknesser and it's only catching the last 100mm at each end.

 

[Fitzroy]

Lots of good advice above. Only addition from me is to think about what outcome you want and then work towards it. What I mean is with a bowed board I will often mark the line on the side that I want/hope to achieve. If I find I’m approaching the line on the front end too fast I flip the board and put the other end over the planer instead. Only when nearly flat, or at my lines, do I start with outfeed table pressure.

With badly twisted boards I’ll often take of the high corners by hand so at least it is not rocking over the planer.

 

[HOJ]

I will just add, I quite often use a string line to gauge how much I can reasonably expect to get from a board if its bowed over its given length, but there are occasions you just know it isn't going to, and go and look for another board.