Jointer Length Question

[Brian Tax]

I have heard that the maximum board length to joint is twice the length of the jointer table. Is that twice the length of the total table or just the in feed or out feed side? It seems like it makes sense for it to be twice the in feed length because when you start, half your board would be off the table. So if your total table length is 5' and the in feed table is 2.5' then you could joint a 5' board. If it was twice the total length then you could joint a 10' board, that seems awful long to me.

Thanks, Brian

[Pat Germain]

Don't know where you heard that, Brian. I doubt you'll find any woodworker who agrees with it. Most woodworkers like the jointer beds to be as long as possible which helps greatly when jointing longer stock. As long as a piece of stock is long enough to safely move across the cutting heads, it can be jointed.

Perhaps you misunderstood what you were hearing about jointers and bed length. I know I've certainly misunderstood things I've heard about woodworking. The good people here on SMC set me straight. :)

[Brian Tax]

For clarification, I want to know what is the longest board you should joint on a jointer based on the jointer bed length.

[David Romano]

I have heard that you only want to joint boards that are twice the length of the jointer table...
Thanks, Brian

I assume that you mean up to twice the length of the jointer table. I'm not real clear on the recommendation either, but I can tell you you that the infeed length is more important. My parallelogram jointer has a longer infeed table and the total length of both tables is 76".

David

[John Lucas]

Brian,
I too don't know what that meant but I would guess it is based on the balance you have on a board. If you have a 3' infeed, you could put a 6' (minus a few inches) on the infeed and it wouldn't tipple off the jointer. That might be a pure way of loooking at it but not one that you will be able to have all the time. You need to have a long enough infeed area so that you can hold the board to firmly on that area. With extension rollers, I have certainly jointed longer boards.

[Tim Thomas]

Brian, the general rules of thumb that I have picked regarding board length and jointer usage are:

(1) don't attempt to joint a board that is shorter than 12 inches long
(2) you will get the best results from your jointer if you joint boards that are no more than twice the length of the outfeed table.

The first "rule" makes a lot of sense, because it would be very difficult to safely move a board any shorter than 12 inches over a jointer and I would think this is something that you would never want to "disobey". The second "rule" though is really more of a guideline or recommendation on getting good results from your tool. Certainly the longer the outfeed table is on your jointer, the easier it is to perfectly joint long pieces of stock. But that doesn't mean that it simply cannot be done, or that it can't be done safely. I have used roller stands on either side of my six inch jointer (which has infeed and outfeed tables that are about 26 inches long each) to support longer stock. I've run a few boards that were about 6'6" long using that setup, which is stock about 3 times the length of my outfeed table, with pretty good results.

I read some jointer tips in a recent issue of one of my woodworking magazines that helped me quite a bit. (I think it might have been American Woodworker, but I'm not sure...) In the article they recommended focusing on the outfeed table more than the infeed, and transitioning from pushing the stock over the cutters on the infeed side to pulling the stock from the outfeed side. It's hard to describe but it makes sense once you try it and I got better results that way. You start out on the infeed side and push the first few inches of the board over the cutter head, but then transition to putting good downward pressure on the stock on the outfeed side and pulling the remainder of the board across the cutterhead. Keeping the stock flat on the outfeed side of the jointer is critical to getting good results.

Anyway, this is probably a lot more than you wanted to know, but it's Friday and I'm a little bored at work. Come on 4 o'clock!!!

[glenn bradley]

For clarification, I want to know what is the longest board you should joint on a jointer based on the jointer bed length.

It sounds like you are asking how long with only the jointer bed for support; no longer than you can control. On my 6" jointer, that was about 4 feet. On my 8" I have done 6 feet for fun without any trouble (out feed roller). Generally I am jointing shorter pieces as they have been cut to approximate size. I rarely joint a board and then cut it into smaller pieces. I consider this the reverse of what you would want to do.

[Brian Tax]

Sorry, my thoughts got ahead of my writing. That is what I meant, for good results and using the jointer only, what is the longest board you should joint.

Thanks for the info.

[Chris Friesen]

It is easiest to joint lumber if it is at most as long as the shortest of the infeed and outfeed tables. Think of it like this...if you are edge-jointing a board that is crooked, you would normally put it concave side up so that it rides on the two ends of the board. If the board is short enough, it remains fully supported for the entire pass and just the two ends are clipped off. Material is removed evenly from each end, and the board remains as wide as possible. It's almost foolproof.

If the board is longer, then the end "drops off" the table and the jointer ends up removing material unevenly. It's certainly possible to joint lumber that is longer than the full length of the jointer, but it requires more careful technique.

[Pat Germain]

There's no hard and fast rule about maximum length of stock and jointers. As suggested, as long as you can safely control the stock, you can joint it. If you set up infeed and outfeed support, you can go to 8' or more. Jointing 8' lengths is required to build a Christopher Schwarz workbench, for example. Granted, this is going to be easier on a bigger jointer. But you could certainly do it on a 6" jointer if you take your time and do a good setup.

[Joe Jensen]

It is not just a safety thing. Once a board is longer than the infeed bed, you need more than one pass to flatten it. If you visualize a non flat board that is 20" long on a bed at least 20" long. The board will be supported by at least 2 points, and if the cut is deep enough, all twist will come out. Now picture a board longer than the bed. One end of the board will be supported by the low point of the board, but the other side of the bed will be supporting the board somewhere in the middle. You will have to do more than one pass to flatten this board. I can't remember the exact number of passes, but it's a reasonable number (like 3-4 passes) if the board is 2X the length of the infeed bed. The number of passes goes up quickly as the board gets longer. Do a thought experiment. Imagine a 12 foot long board with a big warp. Even if you could hold it onto a 26" long bed, the "flat" reference point would only be 26" long. It will take a ton of passes, and I'm not sure you can even make a 12 foot long board flat with a 26" bed.

[Brian Tax]

Very good points, Thanks, Brian

[Eddie Darby]

You can do an end run around the problem of jointing very long boards by using a combination of various machines to do the job.

For instance .... If a board is very concave, then a Ripping Shoe jig on a table saw will allow you to rip a relatively straight line, which then can be refined/finished on the jointer. Doing this helps to establish a baseline and keeps the wood 'equal to' or 'above' the jointer table surfaces.

What a board that is more than twice as long as your outfeed table does is force you to think!:eek: ....Oh and work harder!:D

[Peter Quinn]

I'm with a few others here. Theoretical maximum I was taught is twice the length of the OUTFEED table. You transfer your focus to the outfeed as soon as possible for a reason. That is your landing pad and reference surface for your newly flattened board.

If you are trying to edge joint a 10' banana bow down on a 6' jointer with a 59" long bed its going to take a lot of passes to get close to straight. For edge jointing long boards some times I'll take a few passes on each end to take the high points off the ends before running the whole length, sometimes I'll snap a chalk line and cut off the high points on the BS. Sometimes I'll put my downward pressure on the middle of the board and run it bow up till its mostly straight. You can also straight line with a jig on a BS or TS or skill saw, then clean it up on the jointer.

Now for face jointing most of these methods run out of steam quick, and that theoretical limit starts to come closer to an actual limit. I flatten lots of 96" long boards 5-6" wide 8/4 for passage door styles on an 8" jointer with a 76" table, more than half of which is infeed. When face jointing longer boards stock selection gets critical and good technique is important. Its funny how quick you can turn a piece of 8/4 into 4/4 trying to take out a bad bow over 96"!:D:D On a short bed jointer trying to face joint long bowed stock you never really get flat, you just keep reducing the the bow and approaching flat. I.m sorry but a small 6" hobby tool just can't simulate the results of a 12" industrial machine with a 96" bed,and believe me I've tried.

[Frank Drew]

I don't think there's any reason to try to come up with any rules on this -- you do what you can do (and what you're comfortable with), and sometimes you might be jointing stock that's longer and heavier than you'd like for the length of your jointer, but what are you going to do, cut that 9' bed post in half just to make it easier to joint? If you can get them adjusted precisely, both infeed and outfeed supports can make a difficult task more doable, but still there might be times when you'll be straining a gut to run some stock accurately across your equipment.

Easy is nice when you can get it, but nobody promised us a rose garden :D.

[Jeff Duncan]

I've done many 8'+ lengths on my Jet 6" jointer and really didn't care too much what the theoretical maximum was. If you know how to use the machine, you'll know when your going to have a problem, like a board being too far out to work. This is worked around very easily by consrtucting a set of simple infeed/outfeed extension tables that can clamp onto your jointer tables. I made a set out of scrap mdf and a couple 3x3 posts. I installed levelers on the bottom of the posts to get the extensions level to the tables. A very simple solution that allows you to double or more the length of your tables. I used mine so much that I ended up leaving them on permanently. I found a depth setting that was good for most of my work and left the infeed table at that height. If you change cutting depths often it's more cumbersome as you'll have to adjust the infeed extension all the time also. But since it only takes several minutes to install you can just put them on when you need to.
good luck,
JeffD

[Cliff Rohrabacher]

I'll run boards as short as 6" across my jointer with no issues safety or otherwise. So long as I can get what I feel is adequate support on the outfeed then I'm golden.

I have jointed and planed long boards and beams (as a long as 10') with no additional table support or extensions.

The shortness issue comes into play when I'm planing. If the wood is already cut to length when it's being fed into the planer ( an unhappy thing) then it's helpful to have some tail support as it feeds in (slight lift on the end of the board as it starts to feed). I've considered an out feed support for the jointing but so far I seem not to need it.

If I make one it'll likely be little more than a spring loaded roller that takes some of the grunt work out of holding the board as it finishes it's pass.