joiner flatness

[e.friedl]

I have an old joiner that I was given recently and I am rehabing it. I was stoning the surface of the tables and laid a straight edge on the tables. There are some areas where light is visible under the straight edge. In a machine tool I would have the surfaces ground flat (flat in the machinist sense). Does anyone know what are the flatness specs for joiner tables?
Ed Friedl

[nuhobby]

Hi, your project sounds interesting but I don't know the answer on the spec.

A year or two ago Nick posted here that new Shopsmith jointer tables are machined as a set (dovetailed together like they are during tool use), so mixing and matching infeed and outfeed parts between different jointer samples may increase their out-of-common-plane error.

Good Luck,

[Gene Howe]

If it's flat for 6" either side of the cutters, it should offer no problems in use.

[billmayo]

Hi, your project sounds interesting but I don't know the answer on the spec.

A year or two ago Nick posted here that new Shopsmith jointer tables are machined as a set (dovetailed together like they are during tool use), so mixing and matching infeed and outfeed parts between different jointer samples may increase their out-of-common-plane error.

Good Luck,

Very true, both tables are always machined together and should always be kept as a unit. However, I have accumulated individual tables where the other table was broken. Since I used to build racing engines, I have been able to machine/cut/sand the mating surfaces between the two tables to get both tables level with each other. This is a very slow process and I would not recommend it to anyone. If you have a good friend in a machine shop, the machine that does engine heads and blocks will do the joiner tables together. I did a set of mismatched tables a few years ago for $50 which removes any warpage or uneven surfaces on both tables. The machine shop I used failed last year and so far, I have not found a replacement shop.

[e.friedl]

Thank you for the info, but perhaps I've been unclear. The surface of either of the tables is not machinist flat. Using an engineer's straight edge you can see light under the edge. I haven't placed a feeler under the edge but the gap is in the range of one or two thousandths. That is what I'm asking about. I do appreciate the point about keeping the tables paired up. And if I have them ground I will definitely have them done as a set.
Thanks again
Ed Friedl
Champaign Il
GO ILLINI

[robinson46176]

The surface of either of the tables is not machinist flat.

Neither is my hatchet...
A good friend of mine does custom millwork for historic structures for a living (and has for many years). A lot of his work goes into historic properties owned by the state of Indiana. He does very high quality work and makes top dollar from it. I wish everybody here could spend a few hours in his shop. Most "modern" woodworkers would be in shock, wondering how he could do even crude woodworking in that shop let alone fine detail work. Some would really appreciate his multi-head molding machines that use stuff like old oak table leaves for tables and riding lawnmower transmissions for part of the material feeders. A lot of his stuff runs in hand poured and fitted Babbitt bearings. Much of it uses wood fences and guides, some with a good bit of wear from many feet of lumber having been slid against it.
Absolutely NOTHING in his shop is "machinist flat"... Nothing...
It is however "adequately accurate" for quality woodworking.
We as woodworkers are unbeleivabily prone to blame any lack of skill we might have on our tools... If only the tool were more accurate. If only the tool had more power. If only the tool had more gizmo's and knobs. If only I could buy an arsenal of precision measuring devices... For many much of this comes from never having learned the basics. Many others are simply that retentive.
Hobby is defined as: An activity that one enjoys doing in one's spare time.
Sadly, today, many are so tightly wound that their hobby just becomes something else to worry about...
Pick up a board, make something...

[charlese]

Neither is my hatchet... ...

Absolutely NOTHING in his shop is "machinist flat"... Nothing...
It is however "adequately accurate" for quality woodworking.
We as woodworkers are unbelievably prone to blame any lack of skill we might have on our tools... If only the tool were more accurate. If only the tool had more power. If only the tool had more gizmo's and knobs. If only I could buy an arsenal of precision measuring devices... For many much of this comes from never having learned the basics. Many others are simply that retentive.
Hobby is defined as: An activity that one enjoys doing in one's spare time.
Sadly, today, many are so tightly wound that their hobby just becomes something else to worry about...
Pick up a board, make something...

Francis - those statements are exquisitely posted. Your thoughts fit into my head and soothe the aches that precise measurements cause.

Yes, Yes, Yes!!! When many of us, are accustomed to, (actually grew up with) automotive machine tolerances and the type of hype that goes along with space age accuracy, T.V. Computers, etc.. We have easily been convinced that these precision measurements should be transfered to a hobby, that historically was a trade, centuries before such accuracy was available.

Some of us actually have machinery as a hobby - That is not a bad thing in itself, as "improved" woodworking machinery can increase safety. Very accurate gauges and metal jigs can be helpful to a woodworker.

However, in our woodworking hobby, machinery by itself is not a goal, but a means to a goal of making items from wood that can be used or admired by friends, family, or clients. I can't believe my family and friends would be impressed for more than a minute by my woodworking machinery. Woodworking hand tools are another matter. They are and have been admired by those folks.

To me, basic understanding of wood itself, is the thing that's missing from our hobby. If we understood wood better, the need for extremely close tolerances, more knobs, more devices would not even be a factor of concern. With that knowledge, we could unwind a bit and better enjoy our hobby, with increased skills.

[keakap]

I guess I'm a lucky guy. Woodworking is not tightly defined, and in my world it includes the collection, caring for and use of fine tools, whether to assist in making things of wood or in simply staring at and admiring the devices themselves.

I've enjoyed having worked in areas that demanded extreme precision, so I'm sorta used to it and don't mind trying for it even in wood.
Within reasonable limits, I keep reminding myself.

But then I guess I could complete projects a lot quicker working in poor light and without a magnifying glass...

[etc92guy]

Couldn't agree with Francis more. "Adequately accurate".

I had my portable table saw ( a folding table with an inverted Skil saw attached ) at a job to cut a couple of cleats in modifying a cabinet to mount to a wall. The cleats had to be 14 3/4" long. Simple, easy cut. But I had left the mitre gauge at home in the table saw. I ended up using the fence. Cuts turned out okay. "Adequately accurate".

I wonder if we find this not acceptable due to all the manufactured furniture we have surrounded ourselves with for a few decades.

Perfect vs. "Adequately accurate". This could be quite a debate.

[JPG]

The critical need of the jointer is that the two table surfaces are parallel. This is why they are ground as a pair. Any slight deviations in a small local area is NOT a problem. These can be caused by normal wear. This parallelism needs to be in both horizontal directions(front to rear and side to side). Of lesser importance(but a desirable goal) is for the cutter shaft to be parallel to the top surface(this CAN be compensated for by adjusting the blade height).