Olly Writes

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Planer Knife-Setting Jigs

A couple of years ago, Rutlands introduced a new knife-setting jig to their range for setting the blades accurately on surface planing and thicknessing machines (I guess you might also be able to use it on some spindle tooling as well). Since its first appearance in their catalogue, I hadn’t been able to find a single review or even a few brief comments from someone who might have bought one… They’re currently on special offer for this week and so, I decided to take a punt!

My new knife-setting jig.

From what I could tell, Rutlands are also the prime UK stockist for this product (as they are now with several other items, imported direct from the US). Of course, this isn’t the only planer knife-setting jig in their range and another model has been around for a while. Several other UK companies offer the same pair of jigs under their own brand name and, if you are interested in those, I would instead direct you towards Axminster’s site, where this very same set is available for less than half of what Rutlands and others are asking! It’s also worth mentioning that Axminster also now stock a deluxe jig – the main difference here being that this one references off the outfeed table, rather than the cutter block. That jig looks ideal for setting blades perfectly to your outfeed table on a standalone surface planer (jointer). But, you don’t want that on a combined planer/thicknesser, unless your tables are set perfectly parallel to the thicknessing bed below… Otherwise, you may well find that timber coming out of your thicknesser is tapered in thickness across its width!!

Attention: DO NOT buy these jigs!!

Back to the ‘original‘ pair of knife-setting jigs…

With thanks to Nick Gibbs of British Woodworking magazine, I borrowed a set of these jigs two-years ago. Nick couldn’t get on with them at the time and, no matter how much I tried, I just couldn’t get the same jigs to produce the same results on all three knives. For me, these jigs are too small and lightweight to hold their own against the force of the springs supporting a blade in the cutter block. There’s a little bit of flex in the mechanism as well – it is only a small amount but, it’s enough to ensure that one knife can be set slightly shallow or proud of the next. Again, in my opinion, this is due to the lack of stature on this model. If they would bigger and heavier, perhaps the results would improve…

In short: I DO NOT recommend these jigs. Although, search through the UK woodworking forums and you’ll find many positive comments from satisfied users… Perhaps there’s a quality control issue, somewhere down the manufacturing line? Have the recent batches improved over ones which were being produced several years ago?

Now, on to my latest purchase

At 4in/102mm long, it’s got the size and strength to give reassurance before you’ve even set the thing on the cutter block. What Rutlands don’t mention on their website is that, the instructions [which are legible, much to my surprise!] advise you to have two of these jigs on cutter blocks up to 20in/500mm in length. Anything greater than that should have three jigs. Well, the block on my machine is only 250mm/10in long and, at almost half that length, I’ve found the jig worked well, when placed centrally over each knife. You might also get away with just one on a 300mm/12in machine but, for anything greater, I would certainly advise the purchase of a second jig.

There’s no fine adjustment on this model, which means you do need to reference off of one knife to initially set the jig – and, of course, you also need a method for setting that first knife accurately in the first place! Nothing is supplied to help you, here. If your machine came with a ‘basic‘ setting jig (as my AW106PT did), I would advise you to use that, one last time. Otherwise, you may be able to use feeler gauges, positioned carefully on a “flat” area of your cutter block.

First of all, put a thick pair of gloves on!!! 😯

Place the jig centrally over one of the knife, ensuring that the middle bar is central over the highest point of the blade. By then releasing the knurled knobs at each end, this middle bar (with two magnets sunk in to its face) will drop down and stick to the knife. Re-tighten the knobs to lock this setting and, there you go – now you can carefully remove the jig and use it to set your others kinve(s) to the exact same height! 🙂

Also, mark each side 'Left' and 'Right'!

Again; carefully lower the jig on to the cutter block so its sits centrally over the next blade and the magnetic feet either side will hold it securely in place. There’s no flex, here, as found on the other models. It does feel solid and reliable. One thing I will say is that, before setting this jig in place, it is a good idea to nip the blades up (lightly) in their rough position. If you leave them exposed too much, the force of the springs below will be so great that you’ll be fighting to get both fit of the jig positioned correctly on the cutter block. If you initially set the knives slightly lower than they need to be, you can then release the bolts carefully; allowing each knife to rise up in to place in contact with the magnetic setting bar.

Never forget your GLOVES!!!

Although this jig is almost half the width of my cutter block, I was pleased to find that it didn’t really obscure access to the five blade securing bolts with a 7mm spanner. You can place these jigs directly over a bolt and there’s still enough room to tighten it up properly. I haven’t experimented with securing the three central bolts and then moving the jig to either side to finish locking each blade in place; simply because I’ve found it to be accurate enough when it’s sat smack-bang in the middle.

So, it looks as though I have found a jig that has enough of that repeatable-accuracy that I’m always striving for. If anything changes in the immediate future, I will let you know. For now though, it looks like a have a real time-saver without the bother of having to double-check your results afterwards. Another thing I noticed with the pair of jigs is that the parts contacting the knife seemed to scratch very easily, which could lead to inaccuracies, later on in life (ie. you’re cutting a groove or channel form the blade, each time you use them, which would gradually see the knives sitting higher and higher…). That’s not something I’ve yet noticed with my new jig; the scratching certainly isn’t as deep. But, then again, I know that the set of knives I was using are overdue a trip to the saw doctor’s anyway…!

You can just see the scratches.

Thanks for reading..

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2 responses to “Planer Knife-Setting Jigs

  1. correawoodworks 08/08/2010 at 22:57

    I am going to be replacing the knives in my 15″ jet planer in the next few days. I use a small dial caliper to set each knife within .001″ of one another. I have a few other stands which hold dial indicators to set the height of the cutter head in relation to the bed. it also can be used to set the pressure rollers, bed rollers and chip breaker. Since using the dial indicator method I have had extremely good results, especially on the jointer. Your three magnet jig seems to be a large improvement to the smaller single post fixtures you show. I will put up a short post showing my method in the next few days.

    -Sam

  2. Mark Begbie 12/08/2012 at 22:01

    I bought the pair of jigs you mention in the article, before I read it. My first, major, disappointment was that they are plastic. As you noted, they have quite a lot of flex.

    After the first attempt the knives were all over the place!! A bit of head scratching later and I took the knife lifting springs out. With that done the gauges worked well, and the springs are in a tin. Getting great results from planer and thicknesser functions.

    The Rutlands jig seems really expensive. Anyone import the full size planer pals?

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