Question on flatness out of lunchbox planer, derusting a #7, and just venting.

[Fred Bryant]

Well, this is probably the wrong forum, but there seems to be a wide variety of knowledge and hybrid woodworkers here such as myself.

I have been a power tool guy, more of a carpenter then a woodworker. I am moving in the hand tool direction, especially since I am lacking any sort of shop now, or in the near future. I have a brand new LN box with some planes in it that has been waiting for me. Now that I finally got a day off, I was going to learn to use them. I am a project type guy, so I am building a Moxon table as my first planeing project.

Got up this morning and it is a nice 17 degrees F. I shoveled the garage apron and pulled out my Unisaw to rough cut the stock. Well, I hit the switch and the saw blade made about 10 revolutions in as many seconds and then nothing. I checked for proper 240VAC and all was good. I tried again and the same. I let the thermo-overload cool until it reset and tried a third time. It started so I left it running until all the wood was ripped, although this is not a smart or recommend practice. When I did shut it down, it would not start again. I figured I will have to look into it after I talk to someone who knows more about motors than I do. Besides that, I wanted to get to building and trying out my new planes. If anyone has any motor ideas, they would be much appreciated.

So I flatten one face of each board with my new #7 and it worked out very well for a first attempt. This is especially considering that it was done sans bench and with the boards sitting on the Bobcat forks. There were a few attempts at sharpening before I got it workable, but all and all I was happy with myself.

I then pulled out the workmate, which lives outside, and throw my 12.5” portable planer on it ( delta 22-560 ). I have used this setup for a number of years without incident. I set up some infeed and outfeed rollers and went to town. In the middle of processing the first piece, the workmate top broke in half. This caused me to get the hell out of the way as the planer, the infeed roller, and the board came tumbling down. Well after the 30 minutes it took me to dislodge the board from the planer, I picked up the mess. The only obvious damage seemed to be a massive bend in the little sheet metal infeed table. I beat it as flat as possible and reinstalled it. I then rough processed all the stock.

I put everything up, came in the house where it was warm. I then hand cut all the top pieces to length with the intention of tweaking everything for the glue up with my new planes. These boards were to be glued up, face to face, to make a Roubo-ish top. I soon discovered that every board had a 40 thousands hollow down the center on each face. That resulted in over a 1/16” gap between the faces of the boards when the edges were tight.

I dug out the planer again, and sent a flat board through it. Surprise, it came out with a 40 thousands hollow in the center. I spent that next 8 hours fiddling with the planer, but could not find anything wrong. Finally I decide to change the planers knifes under the presumption that they might have gotten bent in the spill. After this, when I run a board through, it ends up with a 10 thousands hollow. What I do not know is if this is within the normal range, or do I still have an issue?

In the middle of this, it started snowing. This was fine, except I had gotten so distracted, or frustrated, with the planer, and how the day was going in general, that I left the plane sitting in the snow on the Bobcat forks. So, I need to know the best way to remove some rust spots and to prepare it for storage ( non-use ) for the next month or so.

I guess the good news is I will have another month or so to think about how to fix everything while I am working on the road again.

Thx's, Fred.

[Erik Manchester]

Fred,

Sounds to me like the lumber is cupped slightly and when planed the feed rollers flatten it, and after planing it springs back slightly when released from the feed roller pressure.

Have you jointed the boards prior to planing so that one surface is flat? This is a critical step to facilitate planing and cannot easily be avoided, though some plans exist for planing sleds to allow use of wedges to plane warped boards that are too wide for a typical jointer. In my case, I use hand planes as I do not have a powered jointer, which achieves the same result albeit much slower.

It isn't a blade alignment issue causing the problem.

Good luck when you get back to the shop.

[Jim Matthews]

I gotta see the Bobcat workbench.

That redefines portability.

[David Keller NC]

Fred - I think Erik probably may have it correct. My only comment on that specific problem is that you don't say what thickness or species your boards were. If they're 4/4 thick white or yellow pine, then it's possible that you didn't quite get one face of the boards truly flat with your #7, and the feed rollers on the planer did indeed push the board down as it went through.

But that's nearly impossible with 2" thick oak or maple - a lunchbox planer doesn't have enough feed pressure to alter the board's geometry as it goes through the planer.

The first thing I'd do is carefully check your hand-planing job with a good straight-edge. It's entirely possible to plane a cup or a bow into lumber with a handplane. If one face is indeed flat across its width and down its length, then my guess is that the bed of the planer has been warped by the extreme temperatures you mention. This is quite common with metal woodworking machines. For carpentry on a jobsite, it doesn't matter, but it can frustrate you when you're working to tolerances that are necessary for cabinetmaking.

About your Unisaw - it's hard to diagnose without being present, but it's possible that the very cold temperatures turned the grease in the sealed bearings to molasses. Under those circumstances, the amount of current required to start the motor spinning is huge, and if your extension cord or garage wiring is a long run, the large increase in inrush current may have resulted in a large enough voltage drop to prevent the saw from starting. Because this is a dynamic effect, you won't be able to measure this with a typical voltmeter. You would have to use a clamp-on ampmeter and test the current runnign through the circuit when the saw is first turned on.

The easier way to diagnose the problem is to put the Uni back into the garage, and use some sort of heater to bring the air temperature into the 40's or 50's for a couple of hours and try again. If the saw cranks right up, you've dodged a bullet - trying to start a motor against a large amount of force (the cold bearings) that results in a large voltage drop will potentially ruin the windings on the motor.

[Fred Bryant]

More information:

The material is 6"-6.5" wide by 10' long, 8/4 soft maple.
I am fairly sure I got one side flat across the width as I did test it with a straight edge. Since I only had a four foot straight edge, the length could have had a little bow, twist, or concavity. I did sight down after planing and worked until it was flat by eye.
Somewhere I have a picture of the Bobcat workbench, but it is nothing special: A 12" wide by 5" thick x 9' long cut piece of glue-lam with cleats screwed to the bottom that fit tightly between the forks. The need for a key prevents it from be borrowed on the jobsite, it is infinitely adjustable in height, and also can function as a great field weld positioner. I stuck a couple of big screws in it to capture both one end and one edge of the board being planed ( a cheap planing stop, I can not wait to get to the skill point for my bench build ).

I am very sure that the concavity was being put in by the planner. It seems to be much better now, and might be fine. I just I am not sure since I never measure the flatness it produced before as the work was rough enough that it was not an issue. It is amazing that one can adjust the thickness of a piece of wood, at least in the short term, by about 6 thousands by hand.


This morning, with a little sleep and distance, I realize that all is not lost. I can have more planeing practice taking the cup out of the top boards by hand. I just I am going to have to get a couple of more pieces of maple to make up for the lost width. Also go an email that I have a UPS box from BenchCrafted at the PO Box.


Well, I have to hit the road.

[David Keller NC]

Well, someone could prove me wrong, I guess, but there's no way that a lunchbox planer has enough pressure in its feed rollers to compress a 6" wide, 2" thick piece of soft maple. I'd guess that you've either a planer bed inconsistency caused by extreme temperature swings, or there was enough of a change in temp/humidity from when you planed the wood to when you measured it for the lumber to cup. One other possibility is that the lumber was in compression from the drying cycle, and when you planed off one face, it relaxed.

[Ryan Baker]

It seems more likely that there is a problem with the infeed table resulting from the planer fall and you having to beat the table back in to shape. I would look very carefully into the alignment of all the parts. Same with the cutterhead.

[Fred Bryant]

Updated: Solution.

A few emailed me off list and had the solution. I checked it and it worked, so I figure I will pass it on.

The planer cutter head consists of the rotating head and two disposable knifes, each with a hold-down clamp bar. The screws through the clamp bar holds the knifes down. The clamp bar is relieved to consentrate the clamp pressure on a raised lip on the clamp bar. This raised lipped holds the very edge of the knifes down firmly in contact with the head. Think chip breaker on a plane iron.

The problem is that when the planner jammed and took a big bite, it bent up the lip on the hold-down bar. The bent up lip was only a few thousands, but it allowed the knife to flex up, resulting in a deeper cut.

Hopefully this makes sense. Order two new clamp bars ( ~30$ ) and now the planer cut flat within 3 thousands.

Thx's, Fred.

[Adam Cruea]

Good to hear you go that fixed.

How bad is the rust on your #7? If it's just surface rust, you may be able to take a little pneumatic oil (it's what I use), let it soak in, and rub the rust off. For deep, deep pitted rust, you can use naval jelly.

Another option is, if you have a flat (true flat, like a granite block or floated glass), you can superglue some sandpaper (very fine would probably work) and sand it off. Steel wool could work too.

BTW, if you take wax or pneumatic oil and rub on the plane, it *should* keep rust at bay. Since I've never left a plane in the snow, though, I'm not sure if it will completely solve the issue. ;)

[george wilson]

Well,I wouldn't call it a GOOD day,but a gold star for the effort put into trying to work wood under the conditions!!:)

[lowell holmes]

This isn't April1 is it? :)

[Gary Hodgin]

Look at it this way. At least you didn't lose a finger or eye. I don't think I've ever had a quite so bad day in the shop, but there's been allot of days where everything goes bad. In fact, yesterday afternoon was one of those days.