Tuesday, March 18, 2014

V5.11 - But what about the fence?

We’re still talking about our friend, the jointer. So far, we’ve talked about what the jointer is used for. Then we checked the tables for flatness and being level with each other. Then we talked about setting the knives. I can see two things we left out: Setting the fence and how to level the tables.

Let’s deal with the fence first. A good, flat, properly adjusted jointer fence is a critical feature of a decent jointer. Now, if I were you, the first question that arises is: ‘what does he mean by “good” fence and a “decent” jointer?

That's a couple of good questions, I’m glad you asked.

In my opinion a ‘good’ jointer fence is one that is made of cast iron. I have seen some very low-cost jointers with fences that were made of extruded aluminum. Yes, these were on 4-inch or 6-inch hobby-style jointers but the fence is such a critical piece that even on those kinds of jointers, an aluminum fence can kill your accuracy.

A ‘decent’ jointer is one that I can set up properly and expect it to stay adjusted and not have to fuss with it each time I want to use it. An aluminum fence is usually not that way. The heat and the cold and the movement can all affect the way an aluminum fence acts. Cast iron fences are much more stable and they tend to stay adjusted.

OK, so we have ‘good’ and ‘decent’ defined- here’s what to look for on ANY jointer fence. 1) You want it to be flat. Flatness is always checked by using a machined straight edge and a set of feeler gauges. You check across the width, then lengthwise, then ‘X’ it. Usually a .005 to .010 ‘out of flat’ is within specifications. I’ve seen many aluminum fences be out .020 to .030. That is not ‘good’. A fence that is not flat can cause all kinds of problems and you’ll never get a good jointed edge when using one. For instance, let’s say that you are edge jointing a 1 x 4. You set the fence up, you make sure it is square with the infeed table, but you forget to check to see if it is square with the outfeed table. (truthfully, the only reasons it would not be is because the fence is not flat OR the tables are not aligned properly.) You start your joint and when you get done, you discover that the edge is twisted. So, you have to junk that piece of wood. Another one of those not ‘good’s I was telling you about. 2) The second item on our ‘good’ fence is Repeatability. In other words, when you adjust it properly at 90 degrees, and then move it to 45 degrees, you can return it to 90 degrees and it will BE 90 degrees. Cast iron fences are good about this- aluminum fences… not so much.

Send your questions or comments to:
Toolsmartz@bellsouth.net and we’ll see what we can do to help you. 


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