Need input! Idea for festool-based panel saw

[bg]

Having been fired into some giving some more thought to this, my hope on using the Festool saw and guide in some sort of jig are now much diminished. Well l should say the ability to QUICKLY make several cuts on a large sheet with the accuracy and quality of cut that the Festool gives is diminished. Of course heaving the board onto some saw benches measuring and clamping the guide at both ends, (and then rechecking in case adjusting one end moves the other a knits tit), and then, depending on the cut, sliding the saw to the end, now somewhat at my maximum reach on tiptoes, will do the job very nicely, but just not very quickly.

So to think out a mechanism and procedure to quickly and accurately get the guide rail in place did not seem too much of a problem. However, having spent a few cold hours in the workshop today, I think it’s a non starter. The problem is the guide rails, good as they are for their purpose, I think they are entirely unsuited to being utilised in a jig as projected. They work so well because they sit on the panel being sawed. They have gripping ‘rubber’ so that they can be used without clamps, although I find it preferable to clamp up firm when using the system. The only way the guide rail can be moved easily is when it is clear of the surface, and for sawing the guide rail should be hard to the surface. Add the complications of wanting to saw differing thicknesses then the whole frame (or whatever) holding the guide rail will need to be lifted and lowered accurately. Its all getting too complicated for me. The only way I see of getting Quick and Accurate cuts from large panels without endangering the back through stretching too far (and I agree the smaller cuts are much quicker and easier to make on a saw bench) , is go for a vertical arrangement, keep the guide rail static (and vertical) and to move the wood. I don’t think the Festool rail and saw would work well for this sort of vertical jig at all and another sort of guide rail and saw would be better suited and probably along the lines of the vertical saw Steve Maskery put in his excellent article.

Of course, having already got the Festool saw and guide rail it was most tempting to see that as the basis for a panel cutting jig. Well thinking about all this is almost as much fun and actually making something, so thanks for posting the challenge, but I will have to sit back and see if John can make anything more of it. I’ve still got to sort out a way I’m going to use to handle the initial cutting of 8 x4’s, but I’ve still got the article on the home brewed vertical saw somewhere and I will give more thought to this solution. For now though its still likely to be the big heave onto saw benches, measure, clamp, measure, and cut on tiptoes.

 

[johnelliott]

Anyway my point is that your plan looks great for that first cut of maybe even a couple of big cuts but won't it be a pain for the smaller stuff - my impression being that you are planning to get rid of your TS and therefore won't have this as backup?

I did build a flip top cart to solve the over reach problem and I'll post a pic if you are interested. Its good in a bunch of ways - it locks horizontally at any height so it can hold several sheets and these can be jacked up to slide each one through the saw but like a lot of homemade stuff its massively overengineered and quite space hungry but I cut 12 full panels last week in one day using it and didn't knacker my back in the process.

Sorry if this isn't helpful but I thought I'd offer some feedback from someone who shares your pain! BTW I have to ask - what on earth do you have 3 table routers for - I'm dying to know. :?

Tim, I do the small stuff on my Festool MFT (multi function table). This is basically a table on which is mounted a fence which is at right angles to a Festool guide which can be adjusted for height (from about 18mm upwards for thinner pieces I use a suitable thickness additional baseboard). The fence has an adjustable stop, if I need to cut several pieces I measure the first one, set the stop and cut the rest

I for one would be intersted to see the cart

Three table routers? Well, I mostly make shaker style kitchen doors. One table router is set up to cut the grooves, the other to cut the tongues on the end of the rails. The tongue cuter is fitted with a sliding table (a Kity product, intended for their small table saw, but easily adapted). The third smaller TR just cuts the chamfers on all the edges of all the components.
Now I only have to alter or check the set up when I change cutters for sharpening, thus saving lots and lots and lots of time. I've made the cost of the extra routers and tables back many times over

John

 

[johnelliott]

Bg, again, some interesting stuff in your reply. I also am thinking that the whole thing might just be more difficult than its worth. Having said that, I will continue to look at the various possibilities that stem from the basic concept. Being 6'4" tall I don't find working across an 8x4 table to be too much of a problem, though I can see how it would be for somebody of average height.

I am thinking of making up an adjustable device that could be used to set the saw guide an exact distance from the first cut edge, pushing against the back edge of the guide. Using it at each end could get a reasonably parallel cut. I've started experimenting with bits of scrap wood and results have been reasonable so far. I'll post a pic later, need to get back to work now
John

 

[Anonymous]

Tony
Sounds like you too, work with motion control systems. Do you get involved with motion capture as well?
martin

Hi Martin

Mechatronics (robotics + automation) and vison systems (to close the loop) + instrumentation and electronics are my main areas at present.

What do you work with?

 

[Anonymous]

Intersting stuff, Tony. I thought you would have something to say about this.
Actually, I'm not so much concerned with accuracy of .1mm absolute, so much as I am with keeping the motion of the guide rail perfectly parallel. I
John

For some reason this did not appear in my recent posts lists and I thought it had died since I posted a while back!!

To get what you want, use linear bearings and move the assembly along guide bars by hand. Linear bearings will allow it ot move very freely at small cost and they are self aligning up to a point thus allowing your guide bars to be slightly out of parallel without problems

WWW.RSWWW.COM have bearings and bars

 

[mahking51]

Tony
I work with the video side of movie camera motion control systems. Also provide and operate the monitor systems for animatronics operators who need reverse scan etc. Also underwater systems and microwave.
The most basic stuff I do is to record live action and then playback for the director, a bit boring but it pays the bills!
sounds like you have fun!
regards
Martin

 

[johnelliott]

To get what you want, use linear bearings and move the assembly along guide bars by hand. Linear bearings will allow it ot move very freely at small cost and they are self aligning up to a point thus allowing your guide bars to be slightly out of parallel without problems
WWW.RSWWW.COM have bearings and bars

Trouble is with this approach is that I would need guide bars something like 2.5 metres long. The longest RSWWW show (unless I'm looking in the wrong place) is 900mm. Even if I could find something perhaps sag would be a problem?

Another thought- if I had a bar either side of the table, and the bearings were self aligning, wouldn't this allow the saw guide to move out of parallel if the assembly wasn't completely rigid?

JOhn

 

[Anonymous]

John

The self alignment in the bearings is tiny but should help.

I have used silver steel in the past as guide material because it too is ground to dimension (the bars you mention are) and available in longer lengths

Maybe with the long run you could go for the bearings that are open on one side which will allow you to mount the rail to the backer board at various points along the run using some posts of some sort.

These should do it

http://rswww.com/cgi-bin/bv/browse/...ID=ukie&3282886213=3282886213&stockNo=4232318

 

[radicalwood]

Hi Guys,

Hope you don't mind me putting my two pence worth in.

I think that you will require a rail at both sides, because of the accuracy you require you could just use use mild steel brigth bar. For bearings to run the festo plate on several options are available cheaply off the shelf, oilite bushes (bearing services) or polymer bearings (Igus), you may be able to get the 4 bearings from Igus as samples, if not drop me a PM as I might have some free ones kicking about the workshop for you. As for a very cheep counter look in R.S. they stock counters simular to those that were used on push bikes for measuring distance, you then only need to actuate it with a rotating pin for it to count. One pin per rev on 1mm pitch = 1 count 10 pins = 0.1.
Personally I would go for a M12 thread as a min over that length, or a M16 give a 2mm pitch and turn the ends down to fit the bearings as you need a plane face through the bearing. If you don't drive it too fast oilite bushes or polymer bearings will be fine at the ends.
One thing to check is if you use one screw is will the festo guide twist and cause the bearings to lock.
2 screws has an advantage but I would still still use 2 rails, no load on the screws. To drive both screws the really cheep way is to use push bike gears and chain with a tensioner some where between.

One concern how stiff is the festo guide will it sag ont the work while you are traversing it along, will the traversing pull off the foam under the unit.

Do you have access to cad?. I might be able to send you some drawings if needed. My background is machine tool design and one off specials, which is better than my woodwork :lol: :lol: