Plunge Router Inaccuracy?

[Blackerty]

Hi all. I posted for a while a good many years ago and have now re-joined.
This is written to request some feedback on the real world capability of Festool routers in deep plunge situations requiring high accuracy.
We have some Festool equipment (a Domino and an ancient but but excellent original TS 55 saw plus guide rails etc) but have to admit to having balked at the price of other stuff in the range.
I last evening however ran up against the limits of a lightly used (i.e. not worn) blue Bosch GMF 1400 (UK spec) plunge router when cutting a 45 wide x 39 deep x 400mm long parallel sided and flat bottomed slot in beech via multiple passes of about 5mm depth of cut using a 50mm cutting length x 19mm dia straight sided bit.
The Bosch performed acceptably on previous bearing guided profiling work, but proved very disappointing on this admittedly demanding application. (details below)
It's for replacement as there's number of scenarios coming up where high accuracy in deep plunges will be required. e.g. cutting deep mortises.
Festool is perhaps the obvious choice for a high end and hopefully precision router - people presumably pony up the premium price for more than bragging rights. It'd hurt badly though to pay out almost €1,000 for say a 1400EQ only to find that it wasn't much better - so hence this post.
Some experience based feedback of similar deep plunge precision work with this or a similar model would be appreciated. Also more generally on exactly what real world capabilities differentiate these routers from the mainstream.
The situation that developed with the Bosch was as follows:
It was set up with two fences on extra long mounting rails - with the fences bearing on the opposite and parallel sides of the work with the router in between. The fences were pushed in tight to the work (to the point where they were generating quite a lot of friction) - they definitely did not permit movement.
Despite this it turned out that when plunging the cutter was going perhaps 0.3mm deeper than the stop setting at the plunge point - so that its end was leaving a circular impression in the otherwise flat base of the slot. Put another way - when the plunge was locked it was lifting the cutter back up to the set height.
The cutter was also when plunging tipping out of vertical enough to very obviously mar the sides of the slot at the plunge points.
The body and cutter were also tilting enough to deliver an inconsistent depth of cut upon hitting the offset depth stop.
It likewise emerged that while the plunge was unlocked the cutter was being pulled about 0.3mm past the set line of cut by the cutting forces - enough to move it from one side of a pencil line to the other.
Examination showed that these inaccuracies were down to sloppy tolerances in the guide posts - that the cutter was moving around while plunging.
The assembly is pretty rigid once the plunge lock is done up (tight) but that's not much help while plunging as above.
A fixed base router clearly doesn't suffer from this problem, but it would be difficult and risky to cut this slot without plunge capability.

Thanks

 

[luvmytoolz]

I'd strongly consider the OF2200 myself. The sheer power is astounding while being very ergonomic despite the size and easy to control, and extremely smooth in operation. It's easily the best router by far I've ever used, and I own a fairly indecent number of routers.

I've used mine to really hog timber and it does this supremely well without labouring. Whereas while the OF1400 is a truly sensational router, there's a noticeable performance and power difference on very aggressive cutting.

 

[woodbutcherbower]

Welcome back !!

Another +1 for the OF2200. I'm a professional joiner, I've used every conceivable machine during a 37-year career, and the OF2200 is simply in a different league to anything else. Nothing even comes close. I build a lot of doors, gates etc, and routinely cut numerous deep mortises (think door locks with a 76mm deep backset) - pretty much the exact scenario you describe - along with things like 2m long x 30mm wide x 60mm deep trenches in gate rails for panel inserts. The results are always flawless and exact. It's exceptionally engineered in every possible respect, the ergonomics and user features are incredibly well thought-out, and it’s an absolute joy to use. To me - it epitomises the phrase "A good tool only hurts you the once - when you dig deep and pay for it. A bad tool hurts you every time you use it."

You didn't mention the width of the stock you're going to be machining - but the 2200's big. And heavy. The most important thing to ensure when deep mortising is that the router base is always sitting dead flat on the stock face even when making the initial plunge - and always bear in mind that any error (irrespective of the stock width) will be cumulative as you go deeper - just one-fifth of a degree out of horizontal can rapidly become a 2-3mm mis-cut by the time you reach the bottom of the mortise. If you're working with stock which is narrower than the machine's base, spend some time building a sled with adjustable either-side fences. There are plenty of guys on here who I'm sure will be happy to help with this.

The OF2200 is the most expensive half-inch router on the market. I'd also dampen your day still further by stating that you’ll only achieve a restricted proportion of its capabilities unless you also buy the accessory kit for it (ZS-OF-2200M, part no. 576832). This contains multiple quick-change bases, a parallel guide with its rods, multiple guide bushes, and other useful bits. If the cost scares you to death, it's worth seeking out the lightly-used machines on eBay which come up from time to time.

Failing that - Festool (I'm assuming you're in the UK?) offer a 14-day money-back guarantee providing you register the tool immediately after purchase from an authorised dealer. So if it doesn't do what you need it to - it will cost you nothing to find out.

I hope you get fixed up.
Kevin

 

[SoonerFan]

+1 for the OF2200

As has been mentioned the OF2200 is a super powerful, balanced , and capable router.  When paired with the accessory kit it is also very flexible.  And yes it is expensive.  But it appears you have a fair amount of this type work coming up so having the right tool makes a big difference.

Additionally, I believe in the UK if you buy the router from a proper dealer you could test it out and if not satisfied return it within 14 days for a refund. https://www.festool.co.uk/service/money-back

 

[rvieceli]

You might want to try a spiral down cut bit if in fact you are using a standard straight router bit. might be a bit more civilized

Another option would be to eliminate the plunge and use either as fixed base or lock the plunge. Use a drill bit larger than the router bit and drill a hole slightly less than the full depth and use that hole as you starting point.

Ron

 

[petar73]

I had the same problem with my bosch gof 1300 and finally decided to get a better router and bought of2200 and later of1010 as well and now considering getting of1400 for site work as I don’t have to carry two routers. The festool routers hold the settings and I don’t have to think about the tool but concentrate on my work and my shortcomings.

 

[Crazyraceguy]

As a confirmed router hoarder, I can say that I have never needed more than the OF1400, before going to the router table. My biggest(highest advertised power) router is the 3 1/4HP Triton. It is the best I have found for that application.
Hand-held though, it's the OF1400 for me, but I have never tried an OF2200. If the OF1400 can do the job you need, it will save you a lot of money.

 

[luvmytoolz]

As a confirmed router hoarder, I can say that I have never needed more than the OF1400, before going to the router table. My biggest(highest advertised power) router is the 3 1/4HP Triton. It is the best I have found for that application.
Hand-held though, it's the OF1400 for me, but I have never tried an OF2200. If the OF1400 can do the job you need, it will save you a lot of money.

As good as the OF1400 is, and it is exceptionally good, it's very noticeably different to the capabilities and performance handling of the OF2200. Not putting down the OF1400 at all, it's just that the OF2200 is a truly unique and amazing beast!

 

[Blackerty]

Thank you very much for the welcome and enthusiastic feedback guys.
I'm in Ireland and a retired engineer.
I've attached some pics showing the set up and the result. (the marks in the side of the slot are filled in one)
That sounds like a wholehearted vote of confidence for Festool routers  - that they can be set very precisely and hold their alignment including on deep plunge work.
The cost is eye watering, but on the other hand poor quality/down to a price tools are a PIA and an ever worsening problem.
The Festool 1400 model was my first thought (the router would be used for smaller general work too), but it sounds like the bigger model handles well and is worth looking closely at.
Encountering this difficulty with what is supposedly an industrial quality Bosch tool was a disappointment - prior to this project which required a long slot I'd been cutting deep mortises and the like mostly on a mill drill using solid carbide spiral milling cutters. (they cut cleanly and last well)
The parts are for a heavy workbench project - the slots (two the same were cut with the same result in each case) are to accommodate the X cross for the leg vise.
Tilting of the router on the work was definitely not the cause of the problem.
The work is wide (145mm in the case of the leg and 280mm in the case of the vise jaw - the result was the same both times), plunging was accomplished by pushing down on the router centreline/top cover, and feeding to cut by gripping and pushing down on the fence assemblies at work surface level to each side. The high up handles were at no point even touched - instant tip over....

 

[luvmytoolz]

[member=81976]Blackerty[/member] I can pretty guarantee the first time you use the OF2200 any thought of the cost will fly out the window. I've never found another router that comes close.

It is also incredibly deceiving as you'd think it would be somewhat awkward to handle by just looking at the size, but it's actually the extreme opposite, Festool absolutely nailed the balance and design 110%!

 

[Cheese]

I'll admit that the router bit marks aren't too pretty but are they visible or do they affect/impact the finished product in some way? It seems like everything is pocketed so there's nothing that's exposed?

However, if there is some visual exposure, then I'd also endorse the use of the 2200.

 

[woodbutcherbower]

I have to say I’m with [member=44099]Cheese[/member] on this. The mortises (save for the vertical errors) you’ve cut are clean and tidy, and the initial plunge marks will never be seen. I’m very much of the ‘I know it’s not perfect but I’ll know it’s there even though it’s invisible’ mentality - but there comes a point where we realise that our time can be put to more productive use. The OF2200’s still stellar, though.

 

[Blackerty]

The marks won't mess with function and will indeed be well hidden guys, but are an irritation when trying to work to a standard.
I find it hard enough to avoid making my own mistakes without my tools getting in on the act  [smile]
Unpredictability in different situations is another angle.
One lesson learned is that it's probably wiser to use a fixed base router for deep cuts when the work can be set up that way.
I'm a bit spoiled I suppose - but for example the ten very large mortise and tenon joints for the stretchers on this project have just been cut on a round column mill drill (mortises using a solid carbide milling cutter) and spindle moulder. Both produce output which is accurately flat and square with no odd marks - leaving a requirement for tuning using chisels and a router plane to get to the fit.
The pics are a bit superfluous but it's nice to get to share with the like minded.
It won't be immediately but a Festool router is now on the list - first to find a stockist where it's possible to take a close look at one to check them out and decide the model and then to hopefully to buy..
Thanks again for the input.
The bench project is proving interesting by the way - it's a first with timbers on this scale.

 

[wmarazita]

Maybe this will help with your initial question.
I have a Festool 1400 and was just making mortises yesterday in white oak. The mortises were .5" wide, 3" long, and 1.5" deep. I was using a .5" upcut spiral bit and a "mortise master" to guide these mortises. I first plunged full depth (1.5") in the each of the ends of the mortise, then repeated side to side passes between the ends plunging and cutting about .25" deeper on each pass. I locked the router's depth during the final clean out pass. I used Festool dust collection for the operation. There was plenty of power and the 1400 didn't struggle at all during any of the cuts. Results: The initial deep, full-depth mortises each were slightly deeper (like your pictures) than the final clean out pass at full depth for the entire length of the mortise. The walls of the mortises were all perfectly smooth and perpendicular to the face. Personally, I thought the mortises were perfect. I did notice the first two end mortises were slightly deeper, but didn't give it a second thought since they would be completely hidden. I don't own a 2200, so I can't say whether or not this same thing would happen using that router.
Hopefully that helps!
p.s. I would have posted a couple pictures, but I already have floating tenons glued into those mortises.

 

[smorgasbord]

I've not (yet) used a Festool router, but what I see in your photos is pretty typical in my experience. The plunge depth variations are, I think, just the nature of the beast, and I'd be very interested is hearing if any Festool router reliably plunges to the same depth within 0.1mm. Heck, there could be some sawdust getting onto the plunge stop causing that. But your observation that when the plunge mechanism grabs there is some up/down movement doesn't surprise me - maybe you need to keep the router pressed down with the same pressure when engaging the plunge lock? Kind of like using a sliding miter saw where you have to keep your arm movements consistent to get consistent results?

Typically, I try to not plunge straight down. CNC machine software "ramps" the bit into pocket cuts as well. The advantage there is that the deepest cuts are all done at the exact same locked-down position. Any side to side differences are from how to constrict the router via fences/guides/bushings, not in the quality of the router itself.

 

[Crazyraceguy]

Any side to side differences are from how to constrict the router via fences/guides/bushings, not in the quality of the router itself.

I'm not so sure about that, there is definitely a difference routers. The smoothness and repeatability or lack of, is built into the tool. (or not  [big grin])
You can have the best template, or edge guide there is, but when the machine doesn't plunge or at least return to the same depth, like it should, the results may not be what you expect.

Some of it is even down to ergonomics. I have a Porter-Cable 890, which I basically hate. I very rarely use it, because I just don't like holding it. It has plenty of power, holds a bit like it should, fixed base, etc. it just doesn't feel good. too tall, badly balanced.
I would much rather hold my Milwaukee with one hand, than the PC with both.

 

[Blackerty]

Thanks guys.
Interesting that when using a 1400 you Bill are also seeing similar slightly deeper circles at the bottom of the full depth vertical plunges but not in the lengthwise passes.
This is just thinking out loud, but there perhaps are several variables in play.
One is that a lot of chips and dust presumably get spun around under the end of the cutter when plunging vertically - perhaps the cause of the tendency to produce a circular burn mark. Could it be enough to deepen the cut by a hair?
This effect (if it actually happens) would presumably arise even in the case of a router with perfectly tight plunge posts.
A second possibility is that the consistent but slightly reduced depth seen during lengthwise passes is the result of steady feed pressure being applied - which in combination with a bit of slop in the posts might cause the router to tip a hair/lift off the plunge stop/slightly lift the cutter and stay there.
This perhaps was the situation in my case when the Bosch didn't cut quite to full depth for about 75mm on one side at the start of the first slot - I think because I had only lightly locked the plunge. (not enough to prevent slop) This defect was removed before the pics using a hand router plane.
My instinct is that the very consistent depth produced after that was the result of the plunge having then been locked tight so that slop in the posts was prevented - this would have the effect of lifting the cutter a hair too. My slightly variable feed force didn't seem to make any difference in that situation.
The feed force is directly downwards when plunging - which if applied centrally/on the router fan housing should result in firm contact with the fixed stop.
If the posts are perfectly tight then theoretically a plunging router should (will it???) stop at the the same height each time to within a very tight tolerance.
The plunge lock is off when plunging though - so if there is some slop in the posts it presumably could let the router tip down a little towards the side away from the stop to cut a hair deeper.
The circular depression seen under plunges could if the above stands up be the result of the cutter going a hair deeper when plunged, or of it lifting a hair when feeding lengthwise with the plunge locked - or of both and/or in combination with the action of dust and chips under the cutter as described at the start.
My Bosch as before unless I'm mistaken seems definitely to have enough slop to move about a bit on the posts until the plunge is locked. The circular marks under the plunges were in some cases quite deep too - which suggests more going on than just dust/chips under the cutter.
I'm 99.9% sure that whatever was going on was not down to the base lifting off the work or the double fence set up permitting movement other than in the feed direction.
I found too by the way that it was advisable to tilt the router base up a bit between passes to vacuum out the dust which had found its way between the base and the surface of the work.
It's always going to be down to job specifics, but in many cases the circular marks under plunges will not be a problem - in blind mortises etc. They can anyway if they matter when access is possible be removed using a hand held router plane - having first set the router to cut a hair shallow if the depth is critical.
Tilting during plunging which damages the side of a slot or lateral movement which widens a mortise are however more serious problems...

 

[bobtskutter]

On my OF1400 I've noticed the rotating depth stop, the one that spins with 3 different depths set on it, can move very slighly up and down.  I think it's due to the "latch" mechanism that allows the stop to move and then fix in position (i hope I'm making sense).

I find that when you're setting the depth you have to press down hard on the depth gauge to account for the movement in the rotating post.

The movement is only a few 0.1's of a millimeter but can cause the effects being seen.

But, I've learnt that "out of sight out of mind" is a good way to approach WOOD working.  It might be different with METAL work and mechanical systems.

To the original poster, with full respect of your skills please ask yourself if the additional money is worth the additional piece of mind.

Regards
Bob

(edited to correct stupid spelling mistakes)

 

[wmarazita]

Maybe try a test where you do everything exactly the same as you have been and make your complete mortise, except do not plunge to your final, final depth (stay shy of final depth by .3mm) and remove 99% of the material. Then make one final sweeping pass to rout out the final .3mm of the entire mortise, taking care not to push down too hard at any time. I'm not sure how you could do this repeatedly since you would have to reset your depth stop, but it might give you useful information about the cause.

 

[woodferret]

I'll echo Bill on doing a cleanup pass.  We don't full final on CNCs plunges either, even with a spiral (probably especially with up spiral) and chip evac.  Set your final depth on the turret.  There usually is one turret position with a set screw - so set that one to be shy.

If your turret doesn't have that, build a quick 'cap' that can go over one that'll give you the spacing required.