Adjusting Bosch PHO 100 planer blades

I acquired an oldish Bosch PHO 100 planer and having cleaned it up I'm trying to adjust the blades. It seems very hit and miss on this machine.

The blades (755), see exploded diagram

formatting link
held by a flat slotted plate (51) that is held by 2 Allen screws. After adjusting, these 2 screws are covered by a further curved retaining plate (52) that is held by 3 more Allen screws, so there will be 5 altogether clamping on the first flat plate. The bladed have grooves in them that locate them in a fixed radial position against the flat plate. They can be slid out sideways from the plate once the curved cover is removed.

I suspect that I should not have loosened the flat plate at all, it possibly being a factory setting, but this machine was old and had muck sticking the blades so it wasn't apparent that they should slide out!!

The flat plate is slotted to allow the blade height and angle to be adjusted but there is no micrometer adjustment of any kind, you just have to loosen the screws a bit, try to move the blade slightly and re-tighten, then check the blade height and paralell-ness.

I'm attempting this by clamping the planer upside down with the cut depth set to zero, and laying a strip of wood over the blade. Rotating the blade cylinder assembly (850) will then moves the wood an amount proportional to the blade protrusion. The idea is to get near zero movement of the strip at each end of the blade (and for both blades), showing the blade is both parallel to the sole plate and hardly protruding at all.

The trouble with this planer is that the slightest loosening of the screws lets the blade move, hence it is a frustrating business to get it right. By the way, I am not fitting the curved plate (52) until I have completed the alignment checks satisfactorily.

Axminster sell an alignment gauge, but it won't help with stability of the adjustment

formatting link
I missing something here, or does anyone have any tips for making the task more predictable.

Phil

Reply to
Phil Addison
Loading thread data ...

Magnets. Those little tiny neodymium disc magnets. Stick a couple of them to the thing and it should hold everything steady while you get it clamped up.

Reply to
Skipweasel

Small dab of Araldite Rapid each end and leave for 30 minutes before inserting screws? If that works, it wouldn't do any harm to put a touch of locking liquid on the threads either.

Reply to
Andy Cap

In message , Phil Addison writes

I have an ancient Wolf planer which is supplied with a sharpening jig and a blade adjustment/depth of cut device. I can't see from the diagram if your blades are mounted in a similar fashion.

On the Wolf, the blades are secured to a *mount* which has a 90deg. flange: fitting tightly to a slot in the rotor. The whole assembly then clamped to the rotor with a further set of screws.

Having sharpened the blade, it is then loosely assembled in the *mount* and then adjusted for cut. The adjustment jig has a slot similar to the rotor and a 90deg. reference face which the blade edge should just touch. Clamp screws tight and reassemble to the rotor.

I suppose an *L* made up in hard plastic might do but perhaps a proper jig is available from Bosch?

regards

Reply to
Tim Lamb

I've just checked on my Bosch and the flat plate isn't level with the base plate when set to 0. At it's highest point, it's level with the central cylinder and about 25mil shy of the straight-edge. The 25mil is then the amount the blade extends out, once in place.

Reply to
Andy Cap

That sounds promising, where would you get those magnets?

Phil

Reply to
Phil Addison

That's pretty much what I described.

As is this one; I'm looking for tips to overcome that.

Phil

Reply to
Phil Addison

Google for "rare earth magnets" of "neodymium magnets"

There are loads of places selling every conceivable size and type.

I have some fridge magnets - heavy duty. One can hold several heavy envelopes :) Also have a couple of fridge magnet key hooks that can take a real lumpy bundle.

Reply to
Tim Watts

Getting the projection the same for both and true with the cylinder (though that is probably taken care of with the slot) is probably more important than making sure that zero on the markings is actually zero cut.

Certainly aim for zero = zero but I wouldn't loose any sleep over it. When using the plane just adjust it so it takes what you want it to take not what the numbers say.

Reply to
Dave Liquorice

Thanks Tim (and Skipweasel), I didn't realize they were so readily available, and cheap too, e.g. 10 for £5.50. I'll be ordering some off ebay.

Phil

Reply to
Phil Addison

Plenty on eBay.

Reply to
Skipweasel

You'll find dozens of (often frivolous) uses for 'em.

--=20 Skipweasel - never knowingly understood.

Reply to
Skipweasel

Thanks for the various advice. In the end I tightened the blade holder just enough to hold the tungsten carbide blade in position, then used the thin 2" wide blade of my 90 degree square to push the TC blade and the flat holder flush with the sole plate, and then tightened it up. At this stage the TC blade will still slide out sideways from the flat carrier. Screwing on the curved clamp plate with the 3 Allen screws bends the blade holder slightly to clamp the TC blade against the rotor. Taking the drive-belt cover off makes it easier to turn the rotor.

Testing again with the 2" flat blade verified that the cutter remained both parallel to the sole plate and at zero cut. With slight finger pressure on the blade of a 90 degree square you can feel the cutter just scraping it as you turn the rotor.

This was easy to do and overcame the hit and miss (well mainly miss) of the first method I described. And the planer now makes beautiful cuts after its makeover.

Phil

Reply to
Phil Addison

Brilliant Iwas trying all sorts to get it right but as you say the new blades kept moving so I'm going to try the magnets which I just know is going to work it will give me time to clamp them up while still in the correct position. That's a really good tip thanks'

Reply to
jeffrey burrows

It worked although the magnets were a bit of a bugger to control with my one and only hand on the ends of the flat plate. Once set I just nipped each of the two screws lightly getting progressively tighter until the flat plate ceased to have any movement with my finger pressure. All the while checking the blade height. I was using a 300 mm metal ruler as my straight edge and checked it was just below brushing this straight edge set across both planer surfaces at the blades zenith, on the steel cutting roller, between the both the zero datum surface on the actual planer and on the cut depth surface also set at zero, after each action. From my observations the flat plate sets the blade height. I set the longer curve on the top cover toward the blade. The top cover plate actually clamps and stops blade movement laterally (left and right). from what I can see. Anyway I'm back in business again with this great little hand planer Thanks again guys

Reply to
jeffrey burrows

replying to Phil Addison, GadgetKing wrote: I have a PHO 100 and had the same problem, however by loking at some other Bosch instructions the answer ios thus. The blade holder sits on a slightly raised ridge, you must align the back end of the blade clamp with the edge of the ridge. Note the ridge is about 1/1.5mm high and runs down at an angle. I chose the top end of the ridge. It seems to have worked.

Reply to
GadgetKing

replying to GadgetKing, rde42 wrote: I expect he's fixed it in the last eight years. CLUE: look at the date.

Reply to
rde42

Probably got it sorted in the eight years since he asked the question.

It really is a waste of time responding to posts from Home Owners Hub.

Reply to
F

I can understand why it happens. I have done it a few times myself. What has happened (in my case) is that while googling something, a question has come up and I have responded, without ever seeing the date. It only happens that way.

SteveW

Reply to
Steve Walker

Yes if you can be bothered the year is on the site but intuitive and normal it is not. Brian

Reply to
Brian Gaff

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.