Planer knife setting device NBG

[ivan]

There was some speculation about a certain knife setting jig recently, as it was on offer at what looked like an attractive price. I fell victim to temptation. Copied below are the comments I included when I sent it back

A planer requires the blades setting at the same height, and at the same time to that of the outfeed table, and to within a couple of thousandths of an inch. This device as new has a backlash of around 5 thou, which can only increase with use. It is also made of plastic so thin, that the magnetic attraction of the blade-holding magnet distorts the body preventing accurate readings. Further, there is no way of reliably attaching it in the same position relative to each knife. This makes an accurate reference to the outfeed table impossible to obtain, and the height of the three knives varies unacceptably. It is far less accurate than the no cost "drag a stick forward by 2mm" method. Thus, it is not fit for purpose, I have to reject it, and so I intend to return it to you for a complete refund of £25.90 which I am advised I am entitled to, under consumer protection legislation. I look forward to receiving my full refund from you within seven days.

I subsequenly spotted a 'real' Panhans pair in an old catalogue for about a hundred quid, so no surpise these Chinese jobbies are NBG!

 

[p111dom]

Very odd mine were fine and I have used them to set both my planer and thicknesser with great sucess. I understand what you are saying about backlash but once set I have locked mine in place meaning I can reset blades in the same position as before I removed them very quickly. As for no reference point the instruction do not say so but you can see from the pictures that the knife magnet is set nearer to one foot than the other. This nearer foot you just align with the start of the machined grooves in the cutter block within which the knifes are mounted. I guess it's the way you use them. (not that I'm saying you are using them incorrecly) I don't attach the magnets and then wind the blades up. I already had the knifes set using a combination of the drag stick method and a micrometer to a setting that worked. I just then set the jigs to the current blade height and locked them off. I now leave the blades loose when remounting, stick them to the jig which I never adjust and then lock the blades in situ. Very quick, very simple and no need to do trial and error with the drag stick method. It's not how they say to do it in the instructions but they always show adjustment with the cutter block removed which isn't always possible. I checked my setting blocks with a micrometer when I recieved them to see the difference between the pair and when they both read 0 the difference was within 3 thou, more than good enough for woodworking and the accuracy of the scale or any backlash is of no consequence if you don't adjust them. To be fair they certainly don't work as described which is grounds to send them back but never the less they do work.

 

[ivan]

My knives were set OK, so I tried for a reference setting for later use. (The jigs I'd seen before have a notch so they catch on the block exactly the same each time, but it's guesswork with these). As the knife holding magnet approached the knife you could see with the naked eye (let alone a dial gauge) the body distort under the magnetic attraction. The backlash makes it impossible to know exactly when the magnet is just touching the correctly fitted knife, so the reference position is accurate to only ~ +/- 5 thou and thus so is the setting referred to the outfeed table - hence my problem with them. Even a 5 thou error is huge by the 'drag a stick' setting method. On reflection, as they come from Taiwan, I guess they may be produced for the north american market, where a thicknesser is called a planer, and on which machine these problems would be less serious. However in the UK a planer has an outfeed table to which the knives must be set...Perhaps the vendor does not know about this distiction?

 

[OPJ]

I've been playing with a set of the ones from Rutlands recently and one of the most important things I've found is that you need to keep each jig dedicated to a specific end of the cutterblock as they're not 'calibrated' the same on the vertical scale. There was between 1~1.5mm difference between the two that I have used.

I tried following the instructions but they don't make an awful lot of sense. I can see how you're supposed to lower them so they're flush with the cutterblock first and then raise them by 1.1mm, for example.

I used my existing setting jig that came with the machine to set the knives and then carefully set the jigs to this. I find it works fine and saves me the hassle of having to press down against the springs with one hand and try to tighten the bolts with the other at the same time. £40 still seems quite dear though.