Jointer bed length

[legenddc]

I'm curious, is there a rough rule of thumb for jointer bed length to how long of a piece you can typically flatten? I know everyone says avoid the benchtop ones but they have to work up to a certain length. I'm a long way off from getting one soon unless a great deal falls in my lap but want to be prepared ahead of time.

If a benchtop jointer has a 28" bed and a freestanding 6" jointer has a 48" bed or 72" bed what size materials can you work with?

[Chestnut]

I swear the rule of thumb I've read was the length of the beds plus a little bit. I can joint an 8 foot board on my PJ882 pretty easily which i believe is ~83", but a lot of that will come down to technique as well.

My understanding is the bench top jointers are not recommended because of their lack of rigidity not their overall short bed length. In order to joint longer boards more weight is put on the beds causing them to deflect and the overall process is then inaccurate. I believe @wtnhighlander made good use of a bench top jointer on some long material utilizing the machine in a very inventive way.

[legenddc]

I saw that where he had it upside down. I'm not looking to get a benchtop jointer was just trying to figure out the differences.

My dad has a 6" jointer with a 45" bed and once my community woodshop opens back up after the pandemic I'll have access to a 12"(?) one if I'm working on something really big.

[Tom King]

Length of board is not limited by the length of the jointer bed.  Longer bed just makes it easier.

[wtnhighlander]

2 hours ago, Tom King said:

Length of board is not limited by the length of the jointer bed.  Longer bed just makes it easier.

A LOT easier, when the boards are really big and heavy. I don't know about the deflection that @Chestnut mentioned, but if a board is twice as long as either the infeed or the outfeed table of my little benchtop jointer, balancing the board as it starts and finishes begins to get sketchy. I feel like that sketchiness goes up exponentially as the difference between the board and bed length increases. Not to mention that the fences on these little jointers are pretty flimsy and small. Honestly, I was more comfortable running mine upside-down along that big oak slab than running a 8' pine 2x4 across it right-side up.

[drzaius]

2 hours ago, Tom King said:

Length of board is not limited by the length of the jointer bed.  Longer bed just makes it easier.

True. And if it gets hard to handle the long stuff, bed extensions are easy to make & very effective

[derekcohen]

Unless one is building something very long or very tall, where a single stretcher section is required .... and I believe that this is extremely rare ... then a shorter jointer is more likely to be the appropriate machine.

Fact: wood moves, and twists and cups, especially through the drying process.

Flattening long sections will require the removal of more wood than flattening short sections. Solution: always cut the wood into the sections to use, and then flatten them. Do not attempt to flatten the full length of the rough cut stock.

A benchtop jointer would work well for someone building small pieces.

Regards from Perth

Derek  

[legenddc]

Thanks for the input everyone

[gee-dub]

If you think about it, obviously any stock that is not fully supported by the tables or outboard supports will most likely not mill correctly.  A jointer cutterhead does not change plane.  If your material does during the feed you will foul the cut.  Although I wouldn't want to, one could joint long material on a benchtop with adequate outboard supports.  I have a fairly long set of beds on mine and still use supports for anything that is not fully supported on the tables.

[wtnhighlander]

Excellent illustration, @gee-dub. The stock should be fully supported alng its entire length and in plane with the beds to achieve a proper cut. Single-point support, like rollers or the extension bars some benchtops have, just don't do the trick.

[derekcohen]

Gee-dub

I am curious whether you plan to use that length board, or will cut it up? If cut it up, why not do so before jointing?

Regards from Perth

Derek

 

[gee-dub]

15 hours ago, derekcohen said:

Gee-dub

I am curious whether you plan to use that length board, or will cut it up? If cut it up, why not do so before jointing?

Regards from Perth

Derek

 

I reduce the size of blanks before milling whenever possible for all the obvious reasons.  This is a blank for a long, thick, painted piece of trim in a saloon so, it is just a bit bigger than the final dimensions.

I totally get the reason for the question and for the sake of sharing I should probably not use phrases like "all the obvious reasons" if I am trying to add some value in a forum environment .

The "obvious reasons" for breaking down stock before milling may include:

• Shorter lengths and narrower widths minimize defects such as crook, bow, cup and twist.  A four foot board with a 1/4" bow can take a lot of milling to square up.  An 18" section of that board with only 3/32" of deviation takes less.
• Parts broken down and left to re-acclimate can be more stable once final milling is performed.
• I'm getting old and smaller parts are lighter 

Some reasons for milling large blanks that are not for large parts might include:

• Face and edge jointing to prepare a large blank for re-sawing planks or veneers.
• Economy of effort if you are making a large number of duplicate parts; a series of 6" lengths of a given dimensional blank.
• The end dimensions of the parts are too small for safe milling operations.  Examples might be shaped profiles that are ripped off to make trim, short, fat or just plain awkward shapes that are better cut off of a larger "handler" blank.

 

[Tom King]

When I have a long, heavy board to joint, I use my smallest jointer.  The way the wheels are on it put them closer to the center of gravity.  Not being able to get the extra rollers exactly the right height, I set the roller a little below the outfeed table height, and let the jointer slowly tip over until the board barely touches the roller.  I have a strong helper for this job though.  He helps steady the tail end until I can handle it.

This is sitting with the jointer tipped up.  This was a piece of old Heart Cypress, and heavier than it looks.  I needed 92" pieces out of it, so this is probably just slightly less than 8' long.

My first jointer was an old 3' long 6" Delta.  We jointed 16' long 2x12's on it using a similar method, but that jointer was so small that it didn't need wheels.  We just tipped it on the open stand legs.

 

 

 

[curlyoak]

I have a long 8" delta that is long enough for me to do what's needed. On the rare occasion I cant manage alone, I have a well trained neighbor that I like better than my roller. I find the roller must be properly aligned to avoid pulling or pushing the wood away from the fence. For me the neighbor is the better tool than the roller.

[drzaius]

3 hours ago, curlyoak said:

I have a long 8" delta that is long enough for me to do what's needed. On the rare occasion I cant manage alone, I have a well trained neighbor that I like better than my roller. I find the roller must be properly aligned to avoid pulling or pushing the wood away from the fence. For me the neighbor is the better tool than the roller.

Does your neighbor know you call him a tool behind his back? 

I agree about the roller stands. They're just too fussy to get lined up properly. I made bed extensions for my jointer & that works well.

[curlyoak]

I'm blessed with good neighbors. We replace an old fence on the line we share. In a convenient out of the way spot, we installed a gate. A sign of a good neighbor is a gate in the fence that separates us. And you both use the gate. And he really got the knack to hold and receive on the jointer.

[wtnhighlander]

1 hour ago, drzaius said:

 I made bed extensions for my jointer & that works well.

Happen to have any pics? I'd love to see how you set them up.

[drzaius]

12 hours ago, wtnhighlander said:

Happen to have any pics? I'd love to see how you set them up.

I don't & am at work now, but they are just a length of MDF with reinforcing ribs on the back. One end is secured to the end of the bed, the other end is supported by an adjustable roller stand (with the roller removed) so I can get it perfectly in line with the bed.