Feedback on idea for a planer stand

[fitzhugh]

I adore my Shopsmith planer. However, I am not keen on a few things: the pricey knives (oh well, I'll just avoid nails), the need to lift it on and off, and the hassle of using any indeed and outfeed things.

Well, I tried supporting it by the underside of the table instead, just on blocks to test. It had no difficulty raising up the weight of the main body,cutter head, etc. I would not want to do that consistently out if concern it could wear things or stretch the chain, but it has me thinking it's quite possible to have the table stationary.

Since I really need to make a base for it anyhow, make a base with blocks that the table rests on, as above. Use gas springs, as in the power lift, to take the strain off the adjustment mechanism, and have the motor on a lower shelf or similar that is slung below using the threaded holes for the standard clamps. I might be able to just have the motor on a hinged board so it moves up and down that way, would have to test. Otherwise it would be hung from the holes but would have simple guides to keep it from torqueing when running.

This would let me make a rolling cart with fold up in/out feeds. I've got a couple of motors to choose from.

Any reason this is stupid that I'm missing?
Anybody try this and solve all the problems I'll run into for me?
Any suggestions?

I'll post a sketch tomorrow if nobody has a good reason it won't work.
Thanks all,
Fitzhugh

[BuckeyeDennis]

You might run into problems with jackscrew backlash. As designed, the weight of the table preloads the jackscrews in the same direction that the rollers will be pushing them.

If you suspend the planer from it's table, this will preload the jackscrews in the opposite direction. Then when you feed a workpiece, the rollers will try to lift the cutterhead assembly, reversing the jackscrew loading. So I expect that any play in the jackscrews will increase the amount of snipe you get. In the worst case, if the roller pressure is about the same as the weight of the cutterhead assembly, you could get inconsistent thicknessing of the entire board.

[JPG]

Add to that, the weight of the table is less than the weight of 'everything else' so the force required to 'increase' the thickness will be greater than the force required to 'raise' the table. Yes that is confusing(the weight/direction reverses with the suspension change).

[fitzhugh]

Ha, I admit I never came close to thinking about the backlash, and that is quite insightful.

OK, now it may be about to get silly, but humor me
Maybe JPG's answer contains a clue to a solution: what if I use gas springs strong enough to preload it back the right way? I'd have to fasten the table to the stand* so the whole thing doesn't just lift.

The other approach is to add fine adjustments to the *feed supports, using a standard 16 pitch thread to match. I'd just add it to roller stands and not an outfeed table. Might get old very quickly though, cranking one or two extra cranks.

*possibly using magic, I can't go look at what the options are the moment. I remember there are ribs but not much else. I suspect the ribs will be slightly V shaped and not ideal to clamp to. Too bad it isn't the cast iron table, I could just use some big magnets to hold it down

[BuckeyeDennis]

In principal, preloading the head assembly would solve the backlash problem. IIUC, lunchbox planers have the same issue, and the better ones have column locks to address it.

Matthias Wandell came up with a way to use spacer blocks on his cheap lunchbox planer. He just puts blocks of the desired thickness between the carriage and the table, and then clamps everything together with the elevation crank. This not only eliminates the backlash, it also takes frame flex out of the equation.

[JPG]

Question here is how much 'backlash' is there?

If significant I think we have stumbled upon a possible cause(or contributor) to snipe. i.e. backlash could possibly cause the table to 'rock'.

[fitzhugh]

A quick aside: I've used a newer makita lunchbox planer a bit recently. While it runs well, it sure makes me glad for the ss planer one piece table. The stamped fold down wings aren't even flat, each has a significant bow. I couldn't believe the tiny strips of steel that made up the knives, but they are very easy to change. Still, I like sharpening.

[greasemonkey2275]

A quick aside: I've used a newer makita lunchbox planer a bit recently. While it runs well, it sure makes me glad for the ss planer one piece table. The stamped fold down wings aren't even flat, each has a significant bow. I couldn't believe the tiny strips of steel that made up the knives, but they are very easy to change. Still, I like sharpening.

Depending on what model planer you have, you can check http://www.ereplacementparts.com/search ... aner+Parts for the wings. I bought brushes from this company for a Ridgid planer that I was given that didn't work; turned the planer for $250 since I already had a newer model of the same planer.

[fitzhugh]

Thanks - That's such a coincidence: I logged into my computer specifically to go order brushes from them, though for a porter cable router. Will be my first order from them. That and a couple bearings and loctite 680 from Amazon and it should be good to go. I had it all in shopping carts on the sites but got distracted. Thank you in any case.