Shopsmith Forums

A few months back there was a thread about a guy who was getting tapers on his jointer. In this thread there was an interesting discussion about whether jointer knives should be set dead even with the out feed table or slightly above and if so by how much Tonight I was perusing Nick Engler's site and came across a short explanation of why you should set your jointer knives slightly above the out feed table. http://www.workshopcompanion.com/KnowHo ... ck_pop.htm

On the same website, Nick points out that a jointer doesn't ensure parallel edges, which was also debated. http://www.workshopcompanion.com/KnowHo ... Lumber.htm

algale wrote:A few months back there was a thread about a guy who was getting tapers on his jointer. In this thread there was an interesting discussion about whether jointer knives should be set dead even with the out feed table or slightly above and if so by how much Tonight I was perusing Nick Engler's site and came across a short explanation of why you should set your jointer knives slightly above the out feed table. http://www.workshopcompanion.com/KnowHow/Techniques/Jointing_Planing/2_Jointing_KnowHow/Springback_pop.htm

On the same website, Nick points out that a jointer doesn't ensure parallel edges, which was also debated. http://www.workshopcompanion.com/KnowHow/Techniques/Jointing_Planing/5_Truing_Lumber/5_Truing_Lumber.htm

Key point to be understood, is the difference between 'Jointing' and 'Planing'. Each requires a different tool. A jointer for jointing, and a planer for planing.

A jointer can only produce a square edge(the junction of two flat faces) or a single flat face. Granted one of that face pair is normally referred to as an 'edge' when much narrower than the wider 'face'. The jointer only makes cuts relative to the face being cut(the bed is the reference) or an adjacent face(the fence is the reference).

A (thickness) planer on the other hand only makes cuts parallel(if properly set up) to the opposite face.

Thank You for raising the infeed/outfeed issue again. However the 1-3 mil springback compensation is probably out of the attainable range for most of us. I find it interesting that Drew in one Sawdust 'interlude(or whatever)' recommended running a workpiece through the planer a second time to remove such small amounts. The thinking was that the second time. the springback was minimal due to the extremely light cut.

IMHO all this concern about 1-3 mil is not relevant to most of 'us' since it only becomes true with very sharp blades and very precise blade height adjustment!!! Depending upon the abrasive etc. properties of the work pieces, the blade quickly wears down that much.

If you disagree with 1-3 mil, what do you have your planer set for?

That was me that started that thread. The bottom line for me was to raise the knives SLIGHTLY higher than the outfeed table to eliminate the tapering problem I was experiencing. I NEVER expected the jointer to make the jointed surface parallel to the opposite surface.

If you read the last paragraph of those instructions closely on Nick's site you'll see where he describes how to achieve parallel edges while jointing. Properly set up, your jointer shouldn't cut tapers. Or, perhaps technique is an issue.

The idea that jointers don't ensure parallel edges is because the edges aren't parallel to start with. Rough cut lumber has irregular edges, so expecting to joint two such edges and getting parallel edges is impossible. But, jointing one edge, then ripping the opposite edge, and then jointing that second edge should give you parallel edges. Note that Nick says your saw needs to be set up properly to get parallel edges after jointing one edge and then ripping the other. The same goes for your jointer.

pennview wrote:If you read the last paragraph of those instructions closely on Nick's site you'll see where he describes how to achieve parallel edges while jointing. Properly set up, your jointer shouldn't cut tapers. Or, perhaps technique is an issue.

The idea that jointers don't ensure parallel edges is because the edges aren't parallel to start with. Rough cut lumber has irregular edges, so expecting to joint two such edges and getting parallel edges is impossible. But, jointing one edge, then ripping the opposite edge, and then jointing that second edge should give you parallel edges. Note that Nick says your saw needs to be set up properly to get parallel edges after jointing one edge and then ripping the other. The same goes for your jointer.

Knowing a few of these tips is what makes the difference between a woodworker and someone who owns a garage full of woodworking equipment.

When the woodworker finally develops a long list of these tips that he knows, understands and uses, it just might be that he is becoming a craftsman.

pennview wrote: Rough cut lumber has irregular edges, so expecting to joint two such edges and getting parallel edges is impossible.

Agree! I would also add, however, that even if the board has previously been milled S4S you will still get taper if the previously milled board has developed even a slight twist, cup, or bow.

In the process of taking that twist, cup or bow out of one face (or edge), the jointer must take off more material in some places and less in others. The resulting straightened/flattened face (or edge) thus cannot be parallel to the opposing face (or edge) along all points even if the jointer is properly set up and proper technique is used. The uneven distance between opposing faces (edges) will, depending on where the twist or cup was in the board, result in taper or even a double taper. The amount of the taper will depend on the amount of the twist, cup, or bow. That's why, utlimately, you need the planer to ensure parallel faces (after the first face is jointed) or the table saw to get parallel edges (after an edge is jointed).

pennview wrote: But, jointing one edge, then ripping the opposite edge, and then jointing that second edge should give you parallel edges. Note that Nick says your saw needs to be set up properly to get parallel edges after jointing one edge and then ripping the other. The same goes for your jointer.

Agree.

dusty wrote:If you disagree with 1-3 mil, what do you have your planer set for?

I be a bit corn fused! The 1-3 mil was knife set above the outfeed table on the jointer.

I do not have an exact method for jointer blade setting, but probably end up with them slightly high, but my experience is that that wears down rather quickly anyway.

My point was that the majority here do not have the ability to set the blades so precisely.

As far as the planer blades, The object there is to get them set as nearly to identical as possible 9 places(3 each on all three blades).

JPG40504 wrote:I be a bit corn fused! The 1-3 mil was knife set above the outfeed table on the jointer.

I do not have an exact method for jointer blade setting, but probably end up with them slightly high, but my experience is that that wears down rather quickly anyway.

My point was that the majority here do not have the ability to set the blades so precisely.

As far as the planer blades, The object there is to get them set as nearly to identical as possible 9 places(3 each on all three blades).

I don't think you will find a real big difference between the two methods. I used the manual method before I got all the micrometers and dial indicators and I don't see a big difference.

I set left end and right end only. I then bring the center depth adjustment screw snugly up against the blade. So, in reality, I check with a dial gauge in only 6 locations.

If the blades are not set right, a picky user will know it. Now that may only be true if that picky user has used one that is set correctly. There is a world of difference in cut quality. Furthermore, when blades are getting dull, you can hear the difference.

This may not be true if a user is truly casual. I use mine several times nearly every week. If I used it say once a week or less my senses may not be so keen.

I have spent another three or four hours in the shop playing with the jointer today and made not one bit of sawdust. Furthermore, I enjoyed every minute of that time and despite the fact that I have been using the same jointer for over twenty years, I learned a lot.

What I know about using and maintaining the jointer is a culmination of information gathered over the years and apparently that process has not yet ceased.

I was doing this because of questions that arose in my mind about statements made in this and other threads regarding the jointer. Today it mostly involved comments about needing special equipment to perform a good jointer setup.

I believe it can be done with a block of wood, an allen wrench and a six inch steel rule.

But before I stick my nose out too far, I would like to get some feedback from the Shopsmith jointer users here on the forum.

Two questions that I need answered and I would appreciate input from several people - a consensus if you will.

1. With the infeed and outfeed tables set at exactly the same height (in the same plane), what is the width of the opening between the two tables? Mine is just a tiny, tiny bit less than 1 1/2 inches. Two pieces of 3/4" MDF, sandwiched together, will not fit in the opening without a bit of pressure.

2. When the cutter head is positioned so that a cutter blade is at the "top of rotation", how far is the sharp edge of the cutter from the edge of the in feed table? Mine is just a skosh less than 3/4". In other words the cutter head is centered directly below that opening.

If these observations are universally true, then the installation of sharp blades can be completed using nothing more than the tools previously mentioned and the blades will be within .002" to 004" inches of the same height.

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Block of MDF to level infeed and outfeed tables.

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One cutter head at top of rotation.

A short video of the low tech blade height check procedure that I have used. No dial gauge required. Ruler is expected to move about 3/16" with each blade contact.

http://www.youtube.com/watch?v=ybHUddm89Ho&context=C29e7eADOEgsToPDskIvlq4LT1gQUHMF3btQem_T