Wadkin RB planer table alignment

[Guineafowl21]

The machine has a tendency to cut the leading edge of the stock more than the trailing. Using straight edges, I can see the tables are in an upright ‘V’ very slightly.

I have some shimstock (well, an old set of feeler gauges) - some advice would be useful on how to go about it. Pics on the way.

 

[wallace]

The tables are not co planer. Shim the outfeed table to the infeed table. You dont really move the outfeed much unless your doing rebates.

 

[Guineafowl21]

The tables are not co planer. Shim the outfeed table to the infeed table. You dont really move the outfeed much unless your doing rebates.

Yes, I just use the outfeed raise/lower to set the knife protrusion. Should I put the shims under the raise/lower slide and clamp the gib down on top?

 

[Trevanion]

A very small amount of "hump" won't make a massive difference but you can end up with bowed boards if it's severe enough. Typically, when you're losing the cut as you go along it means your knives aren't projecting enough and the piece is climbing up the outfeed table edge ever so slightly, I would check that first.

Having never used the RB I wouldn't know where to start with getting the tables back co-planar, but I can have a rough guess. I'd check if the amount of discrepancy with the tables is the same all the way through the infeed table's travel up and down, checking that it isn't fine in one area but miles out in another as this would indicate an unusual amount of wear in a particular part of the slide or table and would be a more serious problem that's harder to solve than just shimming it as that would just multiply the discrepancy.

If the amount of discrepancy is the same, I would do as Wallace says and shim the outfeed to suit the infeed if the problem isn't the knife projection.

 

[Guineafowl21]

Yes, the knives have crept inwards a bit. There’s some backlash in the adjusters so I’ve been experimenting with either starting with knives high and adjusting down, or starting low and adjusting up.

With the first method, the knives could be knocked back as they hit the wood, with the second, they can be flung outwards a little by the spinning motion.

I think the more significant effect is being knocked back by the wood, so best to start low and adjust up, I think.

 

[9fingers]

Yes, the knives have crept inwards a bit. There’s some backlash in the adjusters so I’ve been experimenting with either starting with knives high and adjusting down, or starting low and adjusting up.

With the first method, the knives could be knocked back as they hit the wood, with the second, they can be flung outwards a little by the spinning motion.

I think the more significant effect is being knocked back by the wood, so best to start low and adjust up, I think.

Quite agree. If there is any evidence whatsoever that the knives can move outwards in use that needs to be sorted out pronto. Could be exceedingly nasty.
Bob

 

[Guineafowl21]

Yes, the knives have crept inwards a bit. There’s some backlash in the adjusters so I’ve been experimenting with either starting with knives high and adjusting down, or starting low and adjusting up.

With the first method, the knives could be knocked back as they hit the wood, with the second, they can be flung outwards a little by the spinning motion.

I think the more significant effect is being knocked back by the wood, so best to start low and adjust up, I think.

Quite agree. If there is any evidence whatsoever that the knives can move outwards in use that needs to be sorted out pronto. Could be exceedingly nasty.
Bob

As far as I can see, it would only be as much as the backlash in the adjusters would allow (the knives are slotted). The RB has an unfeasibly heavy brass guard, which I always use, and keep polished, for no particular reason.

 

[Vann]

...There’s some backlash in the adjusters so I’ve been experimenting with either starting with knives high and adjusting down, or starting low and adjusting up.

With the first method, the knives could be knocked back as they hit the wood, with the second, they can be flung outwards a little by the spinning motion...

As neither of my RB planers are up and running yet I can't speak from experience. However:

I would treat this the same as a handplane iron - adjust in the outwards direction. With the two "clams" correctly torqued down the knives shouldn't be able to move as a result of the centrifugal force of spinning. If they can there's something wrong (not torqued correctly; distorted clams due to previous overtightening*; etc.).

A lot of cutterblocks of this design (including my first RB) don't have slotted knives, in which case knives moving outward due to centrifugal forces can result in serious injury and/or damage to the machine. The "clams" alone should be tight enough to hold the knives. The adjuster slots will probably hold the knives and prevent them being thrown across the workshop at speed - but I doubt they're designed to do that.

* distorted "clams" due to overtightening was the problem with my first RB - and the reason I bought a second (incomplete) machine for parts.

I believe the correct torque to be around 90-100ft lbs? Does anyone have any better info on that?

Cheers, Vann.

 

[wallace]

For adjusting the knives I over extend the knives and then wind the adjusters inwards to adjust the knives. Its a bit of a balancing act to have the clams tight but not tight enough to stop the adjustment.