Helical vs. Spiral Cutterhead for my MiniMax FS35 JOINTER-PLANER? BRAND?

[BentonTool]

Helical vs. Spiral Cutterhead for my MiniMax FS35 JOINTER-PLANER? BRAND?

Brothers,

I am just starting to investigate the purchase of an upgrade to my MiniMax FS35 JOINTER-PLANER.

Any recommendations on Helical vs. Spiral cutterhead?

Any brand recommendations???

WGM TOOLWORKS Cutter head:

OTHER BRANDS???

 

[Mike]

Both of the images show helical cutter heads, and some companies tend to use the two terms interchangeably. The spiral cutter head looks similar to a helical cutter head, but the edges of the carbide cutters are parallel with the shaft. The carbide cutters on a helical head are angled, as in these two images. Here are two images from Grizzly showing each:

Spiral Cutter



Helical Cutter



Another source for the FS35 is Sheartak, but I don't have any information on their quality. From the image on the Sheartak site, the cutter block appears to be a helical, but they call it a spiral.

 

[vaj]

I don't run an insert cutter head but might the type and size of insert fitted be a consideration in selecting an insert cutter head?

There seem to be lots of low cost aftermarket suppliers of inserts on Amazon etc. (no idea what the quality is like) Might it make sense to choose a head which uses a generically available insert? This to avoid ending up locked up into using a single manufacturer's insert type - not at least unless there was some benefit to doing so?

This may not be an issue in practice - but could there be also be considerations to do with the surface finish and wear resistance delivered by different makers/inserts/carbide qualities/insert layouts?

Don't let this hijack the thread, but it'd be interesting to hear of pros/cons and experience. How long does an insert edge last for versus a sharp HSS knife?

I went the route of gearing up with a One Way gauge (fitted with a better quality dial gauge) etc to be able to make quick and trouble free knife changes on a stock Hammer head in about 2 hours - using their higher quality M42 knives.

My only real concern is the possibility that with the emphasis on insert heads that this knife type might stop being freely available.

They re-sharpen well using a DIY jig and waterstones - and last well while delivering an excellent finish.

The machine IS rather noisy, especially with a high airflow dust system.

While supposedly 'drop in' the Hammer knives/system (not sure where the variation comes from) is not in my view accurate enough to be used that way - but it's not a big deal because their quick change system does deliver a very finely controlled and convenient means of knife height adjustment which permits very accurate setting using the dial gauge...

 

[RogerS]

I cannot think of one single advantage of using the old knives over the cutter heads with inserts like the Silent Power on the Hammer.

And many downsides of using knives.

 

[BentonTool]

Silent Power on the Hammer.

Thank you, I never heard of this brand. Will investigate...

Addendum:
It appears that they only make cutterheads for their own products at the moment:

"Silent-Power® cutterblock​

exclusively for Planer-Thicknessers of our brands FELDER, FORMAT4 and Hammer"

 

[vaj]

Silent Power is a trade name used by Felder/Hammer on various of their in house cutting tools and heads Benton.

Some detail on the advantages of insert heads would be helpful Roger.

I'm on stock knives and have never looked closely at insert heads because the machine was bought a few years before insert cutter heads arrived - one major advantage is that it does an excellent job while keeping €1K + in my pocket.

The big downside with straight knives is surely the frustrating trial and error hassle most experience in setting them up - especially the older sprung type. Sorting out a trouble free install routine gets past that..

 

[Jonathan]

I have no personal experience with Helical or Spiral, but have observed folks looking into the options and end up with Tersa.

 

[BentonTool]

Albeit early in the process, I am leaning towards the TERSA® system.
It looks like changing all those little carbide inserts is a real time-consuming PIA!

 

[Mike]

I have no personal experience with Helical or Spiral, but have observed folks looking into the options and end up with Tersa.

When I bought my new P/T (J/P for others), I considered the helical/spiral cutter block. However, I could not find any professional shop within 50 KM of me that used these types of cutters on their production machines. I wanted professional opinions on which was best, but without exception, all used the Tersa cutter heads. Speed, simplicity, and repeatability were the reasons for avoiding the helical or spiral cutters in favor of Tersa for production machines.

The SCM Minimax FS30 series machines were available immediately with the Tersa block, but if I insisted on the Xylent (spiral) cutter, the lead time was at least six months because it was not a common request for European customers. I can change the three Tersa knives in my FS30 in less than a minute. The SCM salesman made sure I understood that once ordered with a specific cutter block configuration, it would not be possible to convert later to a different configuration. The machine would have to be sent back to the factory for the conversion. However, he added that I would not be disappointed with the Tersa knives...and he was correct.

@BentonTool, I forgot to mention the Esta Disposable Blades as a possible option for your machine. The Esta blade kit uses replaceable knives that fit in a holder for older cutter blocks. Similar to the Tersa, the Esta knifes can be flipped over and will self align. The outfeed table is aligned with the knives one time and after that no additional adjustments are needed.

The new website is more difficult to navigate, so it might be worthwhile to contact the vendor directly with your machine specifications. From what I remember with the old site, the blade holders and knives were ordered separately, but after the initial purchase only replacement knives were ordered.

 

[RogerS]

Albeit early in the process, I am leaning towards the TERSA® system.
It looks like changing all those little carbide inserts is a real time-consuming PIA!

But you don't. You have four sides to use and so it's loosen twist re-torque.

I can see the advantage of a Tersa block. I had something very similar on my Sedgwick...the name escapes me.

Re either Tersa or inserts...vs normal knives. Ding a knife and you have to send it off or spend time resharpening. With the other two it's a quick swap out and replace. And aligning normal knives is a PITA.

 

[vaj]

A quick look just now brought up this video for Tersa knives: https://tersaknives.com/pages/tersa-videos

They seem to use centrifugal force to lock.

Do they if changed that fast truly go back in at the correct height? (bearing mind that given truly flat tables around 0.002in above the outfeed table seems to be about right)

 

[Mike]

A quick look just now brought up this video for Tersa knives: https://tersaknives.com/pages/tersa-videos

They seem to use centrifugal force to lock.

Do they if changed that fast truly go back in at the correct height? (bearing mind that given truly flat tables around 0.002in above the outfeed table seems to be about right)

Yes, they do truly go back to the correct height that fast. The method to set the knives after changing them is to turn the machine on. Simples.

 

[Mike]

But you don't. You have four sides to use and so it's loosen twist re-torque.

This assumes the Torx bolt holding the cutter to the head cooperates and doesn't snap off. This is a big concern with production shops as it can put a machine out of business until it is repaired.

I can see the advantage of a Tersa block. I had something very similar on my Sedgwick...the name escapes me.

Was it the Esta-Bruck/Barke set?

 

[Doug]

I’ve been using the Felder spiral block now for over 12 years & put quite simply I would not want to go back to blades, Tersa or otherwise. The carbide tips are just so much better than anything I used before giving a far superior finish.

 

[RogerS]

This assumes the Torx bolt holding the cutter to the head cooperates and doesn't snap off. This is a big concern with production shops as it can put a machine out of business until it is repaired.



Was it the Esta-Bruck/Barke set?

Thank you. Yes it was …I couldn’t remember the name.

 

[Eric the Viking]

I saw a helical block demonstrated at one of Peter Sefton's* open days some years back (I think it was a Jet or Hammer machine). Two things were very obvious - noise reduction, and the quality of finish (It's a paring cut rather than a head-on chisel "thump"). It _ought_ to reduce the power demand (except for the startup surge, which probably wouldn't be any different), and the idea of simply rotating the cutter in case of a chip seems brilliant. I can't see that you'd gain a similar finish from a spiral block, although you would be able to change a nicked blade fast, and there's no re-alignment needed after the factory (presumably).

I've been processing hardwoods recently with conventional knives in a 2-knife block. Setting the knives is a PITA. OK, I can hone them fairly fast, but they dull quickly too. I"m wasting hours, whereas if I had a helical head any interruption would be minutes.

Regarding snapping machine screws, I actually had to resort to a 'pipe extension' on an Allen key yesterday (and the bench vice), to swap a bearing on a brand new Ovolo cutter from a well-known British supplier of router bits. I was amazed at the necessary force (I shocked it free in the end). If it worries you, get a torque wrench and use it!

Anyway, I'm watching this discussion with some envy...

E.

*For those across the Pond, Peter owns https://woodworkersworkshop.co.uk/. He also used to teach, but I think no longer does.

 

[Spectric]

Thank you. Yes it was …I couldn’t remember the name.

A great system, not cheap although the knives are cheaper than the OEM ones but it is really a fix for a problem that you could avoid by buying a machine with something like the Tersa knives.

 

[RogerS]

A great system, not cheap although the knives are cheaper than the OEM ones but it is really a fix for a problem that you could avoid by buying a machine with something like the Tersa knives.

Have to cinfess that although I'd heard of Tersa knives I'd never bothered to look into them. So I had a quick Google the other day with little luck other than to think that they were just like the Barke system.

 

[vaj]

Trying to draw together what has been said and to add a little.

The difficulty with this sort of discussion is that few of us have experience across all of the available alternatives, also that requirements, abilities expectations and machines can vary widely. We tend to end up stuck with what we bought and making the best of that...

Insert heads seem to deliver a low noise advantage which could be very important in some situations. They also avoid the difficulty of setting knives in a cutter head but there's still the requirement to ensure that the outfeed table is accurately set at the correct height across its full width relative to them..

Presuming highly accurate and truly sharp inserts they also avoid the problem of coming up with a reliable knife sharpening arrangement. Some commercial sharpening outfits from my own experience seem to do a pretty crude job - using coarse grits and the like.

Care it seems is needed to avoid stuck/broken screws etc. in insert heads.

It's seems unlikely that an insert head delivers much benefit in terms of quality of finish versus a properly set and truly sharp 3 knife head.

Insert life could be a factor. Original sets can be expensive. It'd be interesting to hear of directly comparable longevity and cost of use experience versus conventional knives.

My experience with M42 Felder knives is that they last well - especially when DIY sharpened to a fine grit in a jig using waterstones.

Given a PT that's accurately set up in other respects and the right set up equipment my experience is also that fitting and precisely adjusting fresh conventional knives is a relatively rapid and trouble free task. (as before about 2 hrs) I've had both conventional sprung and the Felder/Hammer types.

I'm a bit wary (see below) of the Tersa drop in claims if very precise knife height setting is required for fine work - they may well have succeeded but it's a tall order to come up with a drop in knife changing system which will consistently deliver precisely interchangeable/identical knives and place them all simultaneously at the correct height to within less than a thou.

I run about 0.002in knife height (the outfeed table has been reworked to make it dead flat) - some machines may need more to avoid catching. The Felder/Hammer system while excellent in most respects and despite claims that it permitted drop in knife changes when bought definitely does not in the case of my machine...

 

[Mike]

It's seems unlikely that an insert head delivers much benefit in terms of quality of finish versus a properly set and truly sharp 3 knife head.

Hopefully @derekcohen will add his experience with the helical/spiral cutter blocks. He uses wood with complex grain that would challenge traditional straight knives.

I'm a bit wary (see below) of the Tersa drop in claims if very precise knife height setting is required for fine work - they may well have succeeded but it's a tall order to come up with a drop in knife changing system which will consistently deliver precisely interchangeable/identical knives and place them all simultaneously at the correct height to within less than a thou.

I run about 0.002in knife height (the outfeed table has been reworked to make it dead flat) - some machines may need more to avoid catching. The Felder/Hammer system while excellent in most respects and despite claims that it permitted drop in knife changes when bought definitely does not in the case of my machine...

There are lots of YouTube videos showing how the Tersa knives are removed and inserted. Based on my research and first hand observations, the Tersa knife cutter block is the industry standard in Germany, and likely the rest of Europe. If the knives were not accurate for fine work, the industry would not be using them.

The Tersa knives do not drop in to the cutter block the way the conventional straight knives do. The double-edged Tersa knives are inserted into specially machined slots from the one end of the cutter block and slide in parallel to the block's axis of rotation. When the machine is started, the centripetal force of the rotating cutter head seats the knives against the internal grooves in the cutter block. The knives cannot be pulled out of the cutter block.

When the Tersa knife is removed, it must be knocked loose from the seating surface and then slid out through the end of the cutter block. Again, this process is well documented in YouTube videos. To save some time verifying this, here is a video showing how easy and fast it is to remove and install the Tersa knives in a three-knife cutter block.

 

[vaj]

I've seen the videos Mike and know that Derek uses an insert head. I haven't heard his thinking explained in detail.

Most of what I have done is with local hardwoods where with sharp knives tear out typically has not been a problem. Interesting to hear that insert heads reduce tear out in difficult woods. The chances are that carbide inserts hold up better in abrasive woods too.

It's not possible to argue with experience in the case of Tersa knives - if they work they work. My caution (only that) followed from having encountered a drop in claim elsewhere and found that it wasn't strictly true - and from an understanding of the sort of very fine tolerances which a truly drop in and forget system would entail.

 

[Trevanion]

Something to keep in mind is that a lot of the American and Chinese helical and spiral cutter heads aren't designed with chip limiting in mind because there aren't such requirements as there is in Europe, which can make them much more likely to kickback and accidents more severe than conventional cutter heads or European versions such as the SilentPower or Xylent.

If you look at this Byrd Shelix cutter head, for example, you will see there is very little body of the cutter head in front of any cutter and the projection of the cutters looks to be over 5mm from the main body of the cutter head. Should you have an accident with a cutter head it will have a tendency to pull whatever it bites into deeper and deeper into the cutter head in a fraction of a second. Five rows of cutters projecting 5mm could result in a removal of 25mm in a single rotation of the cutterhead, with a cutter head generally turning at around 4500rpm would mean that it turns 7.5 times in one tenth of a second makes for 187.5mm of total removal in a tenth of a second, how long is your hand?



This Zylent cutter head has plenty of body in front of the cutters, which will likely be set around 1-3mm (3mm being the maximum for chip limiting on solid-body tooling) lower than the projection of the cutters. Three rows of cutters projecting 3mm could result in a removal of 9mm per rotation, following the same rule above with a cutter head spinning at 4500rpm, you reach a number of 67.5mm in a tenth of a second, almost three times less aggressive than the Byrd Shelix.



When it comes to performance, helical cutter heads can consume more power and require higher-powered motors to run, but this is usually down to a bad selection. If your existing cutter head is two-knife and you purchase a five-row helical cutter head to replace it you will notice a significant reduction in power due to the increased amount of contact from the cutters, which will result in requiring to take much shallower passes or a motor upgrade to keep up with demand. The shearing action also causes more friction than an adzing action, as per conventional straight knives.

For the vast majority of woodworkers, helical and spiral cutter heads are an unnecessary luxury, particularly if one is simply machining softwood and domestic hardwoods as many hobbyists do. Aside from noise reduction which can be justification for some, where you may find an advantage is when machining extremely hard and interlocked exotic timbers such as Jarrah, Greenheart, Purpleheart, etc... where conventional knives struggle without adjusting the geometry of the cutting angle to be lower to scrape the timber rather than adze, which is a more advanced technique. Tungsten carbide tips obviously will last longer than conventional high-speed steel knives in abrasive timbers with mineral deposits like Iroko and Rosewood.

 

[Eric the Viking]

When it comes to performance, helical cutter heads can consume more power and require higher-powered motors to run, but this is usually down to a bad selection. If your existing cutter head is two-knife and you purchase a five-row helical cutter head to replace it you will notice a significant reduction in power due to the increased amount of contact from the cutters, which will result in requiring to take much shallower passes or a motor upgrade to keep up with demand. The shearing action also causes more friction than an adzing action, as per conventional straight knives.

I was about to type, "well at last, someone has explained it!" (meaning the increased power demand), but then I thought,

"Hang on a minute - you just spent a frustrating evening hand-planing Sapele with a #4 1/2, mentally kicking yourself for a stupid process decision, yet also thanking the Japanese for laminated plane irons. Isn't it easier when you skew the plane across the workpiece?"

Well, yes: it it is a lot easier, especially once the edge goes off my Smoothcut iron a bit. My back and weedy arm muscles quite like the idea, too.

I get that there are more cutters in contact per rotation, but that's over a much shorter length, simultaneously, than a full width conventional cutter block. So does this mean that the power increase/decrease nets out on wide boards, but not narrow ones or edges? Do people push the stock through faster because the cutter block works more quickly with a helix?

I'm not saying you're wrong... yet. I've even seen a YouTube shoot-out between two DeWalt lunchbox thicknessers, one with a helical cutter head and one wit the standard factory-fited conventional block. There was no doubt in that video that the helical block drew more power, but the creator, in my view wrongly, asserted it was because of the additional mass of the helical block. The heavier block would draw more power at startup, but would also have greater inertia. The one useful thing about the test was that they were thicknessers: so the feed speed should've been the same on both machines (no pulleys nor other gearing was changed inside).

Conclusion: I'm still not persuaded that helical setups should, inherently, use more energy for a given task than a conventional setup. Considering my #4 1/2, a shearing cut seems to need less power (yes, friction increases, but the force on the knife edge is a lot lower: it feels like shearing wins this one). It's evidently an issue in practice, but as to the reason, I think there are presently too many variables un-tested for.

E.

PS: I snipped the very sensible comments about safety - they make complete sense (I suspect the Shelix design is cheaper to make...) - no disrepect whatsoever, quite the opposite.

 

[Doug]

The problem is in the design of the different carbide tipped blocks especially with power consumption @Eric the Viking this is Felders video from 12 years ago showing what they say are the benefits of their block

 

[Trevanion]

"Hang on a minute - you just spent a frustrating evening hand-planing Sapele with a #4 1/2, mentally kicking yourself for a stupid process decision, yet also thanking the Japanese for laminated plane irons. Isn't it easier when you skew the plane across the workpiece?"

Well, yes: it it is a lot easier, especially once the edge goes off my Smoothcut iron a bit. My back and weedy arm muscles quite like the idea, too.

But contrary to handwork, it's often easier on machines to work against the grain than with it, though you can end up with significant tear out. Because the machine is cutting short grain, it just chops it off into crumbs of dust, where if you're cutting with the grain you're peeling shavings off, which is more taxing on the machine. It's negligible most of the time but you do notice it when you're moulding something like an arch where you have significant long grain and short grain, the long grain leaves a wonderful finish but you can feel that it's more difficult to machine than the short grain.

Again, there's a big difference between removing a fraction of a millimeter with a hand plane and 3mm+ with a planer.

There's also no relaxation period for the helical cutter head as it's typically constantly engaged with the workpiece, this is why it is so quiet as it's a constant hum rather than the "bang-bang-bang" of a conventional knife, but a conventional cutter block is only engaging with the work 10-20% of its total rotation, with the rest of the rotation being idle.

 

[vaj]

Having just noticed your signature T it reminds of a fundamental aspect of most woodworking machinery and especially PTs - it rings very true.

There's probably quite a bit of variation in how different individuals experience the same hardware. The likelihood is that there's not so many users that get deep enough into set up and tuning to get the variables truly under control.

 

[BentonTool]

The difficulty with this sort of discussion is that few of us have experience across all of the available alternatives, also that requirements, abilities expectations and machines can vary widely. We tend to end up stuck with what we bought and making the best of that...

Very true and well-considered reply.

Some commercial sharpening outfits from my own experience seem to do a pretty crude job - using coarse grits and the like.

I have had the same experience. My planer (thicknesser) blades, sent to various companies for "sharpening", oft were returned with coarse-ragged edges or outright burned edges. I always had to hone them upon receipt. Sometimes it was a laborious task to get beyond the burn edges.
I gave up and started resharpening and honing all my planer blades in-house. I now have a surface grinder to aid in the task, but when I was using a Makita horizontal grinder exclusively, it was quite a chore.

Care it seems is needed to avoid stuck/broken screws etc. in insert heads.

I have the same concerns. A broken hardened screw would be a disaster.
Removing would require consultation with a professional who has an EDM device.

 

[vaj]

Even the original Felder M42 knives BT while sharp are probably not as finely ground as is ideal. Interesting that you gave up on commercial grinding and started doing your own sharpening. Great to have a surface grinder!

My subjective feeling is that knives finished to a very fine grit as well as being sharper also last longer.

The Hammer/Felder items are meant to be disposable but low tech re-sharpening of them using waterstones works very well - using a jig like the one in the pics. This followed by a light wipe of the flat back on the finer stones.

The method is not original - the inspiration came a couple of years ago from a well known US West Coast woodworker who demonstrated it in a YouTube video. (I needed knives and couldn't wait the week or so for a mail order new set to arrive)

Great care is needed when using a jig like this - it'd be very easy to inadvertently slice a finger. Use gloves and a push pad and don't attempt to grip the waterstone by its sides....

The approach would probably also work fine on the more traditional and thicker type of knife. There has been no problem with maintaining a straight edge but the knives get equal attention at all points along their length. The step in the jig (which has to be accurately cut) makes sure that they stay straight. The stones are (relatively hard) Shaptons used after a soak up to 12,000 grit but not with water running everywhere.

One advantage of the Hammer/Felder cutter head is that there is height adjustment at about five points. The thin knives are flexible enough for the height to be easily be set at each point to within a tiny part of thou using a dial gauge.

The pic is a bit misleading in that the angle of the jig is set to be just a hair steeper than the bevel on stock grind to minimise the work needed to get to the edge. It's important to only very lightly nip up the retaining screws as they would otherwise crush the ply and distort the thin Felder knives. The UHMW strips and the lacquer protect the jig in use.

The trick from my point of view is the usual little and often. The first sharpening takes a little longer (a very light touch with the finest Atoma diamond plate can speed this up) but subsequently it's a quick job. I usually do up two or three sets of double edged knives meaning that I have six changes ready to go...

 

[Doug]

A broken hardened screw would be a disaster.
Removing would require consultation with a professional who has an EDM device.

I can only reference felder blocks as that is the only brand I’ve used but in the 12 years I’ve had spiral blocks I’ve never encountered this as a problem in part because you are supposed to tighten the tips to a set torque so the chance of over tightening is eliminated.

That said I have read of Axminster blocks that have had screws seized in them but my dealings with Chinese goods has lead me to believe they really don’t like lubricating anything, so if I was buying a Chinese block of any description I’d be removing any screws & lubricating them from the word go.

 

[Weekend_Woodworker]

I notice on the conversation people saying how long it takes to set up conventional planer blades to the right level. I haven’t persuaded my “investment manager” that I need to upgrade my planer yet so have an old scheppach one. I use some adjustable jigs like these to quickly and repeatable set my blades when I change them over.
I haven’t timed it but it probably takes no more than 10 or 15 minutes to change the blades.

 

[Eric the Viking]

I had some of those... and Freecycled them.

The tables on the Kity can't be lifted, so there's no access to apply them to the cutter block, which is the only steel bit.

 

[BentonTool]

Since my MiniMax FS35 has no springs under the knives, I use one of these magnetic blocks to set the jointer knives.
If you find and mark the top-dead-center accurately, it does an admirable and repeatable job in setting the knives.
That being said, I am still leaning towards purchasing a TERSA® cutterhead...

 

[Trevanion]

It may work with your machine, but you do need to bear in mind that because the Tersa knives slide out of the end of the head that they’re not suitable for every machine, especially thicknessers as they’re usually completely enclosed with large bearings at each end. They work best on surface planers and planer thicknessers with a rebating facility as the operator side of the machine has a smaller bearing to accommodate the extra depth of cut.

For maximum efficiency, I would recommend Tersa every time.

 

[Cabinetman]

Since my MiniMax FS35 has no springs under the knives, I use one of these magnetic blocks to set the jointer knives.
If you find and mark the top-dead-center accurately, it does an admirable and repeatable job in setting the knives.
That being said, I am still leaning towards purchasing a TERSA® cutterhead...
View attachment 33407

Sorry come to this late, I have Tersa knives on my Minimax FS350, absolutely no setting up as has been well described by Mike.
Superb finish on everything I have cut including end grain cutting boards. I have no hesitation in recommending them. Also there’s a better chance the block will fit easily.
Ian

 

[BentonTool]

Sorry come to this late, I have Tersa knives on my Minimax FS350, absolutely no setting up as has been well described by Mike.
Superb finish on everything I have cut including end grain cutting boards. I have no hesitation in recommending them. Also there’s a better chance the block will fit easily.
Ian

Thank you, Ian.
I contacted TERSA and they sent diagrams for two available cutterheads for my FS35.
At first glance, they look nothing like my FS35 cutterhead, but I will need to look closer, and get out my calipers for measurements.
Lookin forward to upgrading...
P.S. The drawings are labeled "FS350", so the cutterheads may be the same for the FS35...
My cutterhead is 14.1 inches, which is somewhere between 350 mm (13.78") & 360 mm (14.17").
They recommend 350 mm, but I think 360 mm will fit...
Any thoughts? Which did you purchase?

 

[Mike]

Thank you, Ian.
I contacted TERSA and they sent diagrams for two available cutterheads for my FS35.
At first glance, they look nothing like my FS35 cutterhead, but I will need to look closer, and get out my calipers for measurements.
Lookin forward to upgrading...
P.S. The drawings are labeled "FS350", so the cutterheads may be the same for the FS35...
My cutterhead is 14.1 inches, which is somewhere between 350 mm (13.78") & 360 mm (14.17").
They recommend 350 mm, but I think 360 mm will fit...
Any thoughts? Which did you purchase?

There is the older FS35, with yellow painted chassis, from the 1990s or earlier. There is also the FS35 Smart, which is a newer model. It looks like they sent you drawings for both.

 

[Cabinetman]

Thank you, Ian.
I contacted TERSA and they sent diagrams for two available cutterheads for my FS35.
At first glance, they look nothing like my FS35 cutterhead, but I will need to look closer, and get out my calipers for measurements.
Lookin forward to upgrading...
P.S. The drawings are labeled "FS350", so the cutterheads may be the same for the FS35...
My cutterhead is 14.1 inches, which is somewhere between 350 mm (13.78") & 360 mm (14.17").
They recommend 350 mm, but I think 360 mm will fit...
Any thoughts? Which did you purchase?

It’s back in the uk so can’t really do much, sorry, it was factory fitted when new I believe.