Incra modification and Hammer K3 - a more sensible approach

[shed9]

Finally got my Incra working on my K3 table saw over the Easter break in a way that makes sense so I thought I would share.

Excuse the state of my workshop, the floor has been a nightmare from day one, I've fitted a subfloor already but it had to come up because of the recent flooding.

Some of you may remember I had embarked on a major refit of my saw some time ago using alloy extrusion that basically outfitted a huge assembly table to the right which supported a standard Incra TS setup. The bench had provision for a router lift to take advantage of the Incra fence to use for routing as well. I did actually finish the bench with an MFT style top and ran the whole setup for some time (apologies I should have updated the thread and if I find the pics of it finished I will post them up for anyone interested).

Despite the setup working well it was cumbersome and took far too much room, especially when the Incra fence was extended out beyond the bench itself. To add to this, I found the bench top too tempting as a surface to place any rubbish I need to find a place for and the benefit of the entire setup did not outweigh the space it took up. I knew the Incra system is space hungry but my workshop is not that big and I wanted my space back more than the convenience.

Long story short, I pulled it all apart, reassigned the alloy extrusion to a purpose built CNC router, put the original K3 fence back on and shelved the Incra whilst deciding what to do with it. I already have another router table with an Incra system so I still had what I need. Anyhow I had a brainwave over the last week and came up withwhat I think is a more sensible use of an Incra system on a table saw.

I bought some 10mm alloy angle from Ebay and machined it up to this;




I then cut a length of 45x90 extrusion (from the original bench) and fitted it all together on my K3;




This allows the Incra wonder fence to bolt on the back and I intend to fit a right hand extension table for my original router lift (a UJK model), this is the setup complete with Incra saw fence, wonder fence and some Jessem TS guides;




I stuck some 3mm UHMW plastic under the fences and the whole thing slides quite nicely. I've done a few test cuts and it works incredibly well. I may redo the adapter that fices the Incra fence to my adapter just to strengthen the fence but all it works as it should. I wll get the alloy anodised over the next week and refit the fasteners with socket caps for convenience.

To me this makes more sense as I get the Incra precision without the dead grey space issue everyone has with Incra. I know it seems like it sticks out front a fair bit but this really isn't an issue and does not impede operation or reach in any way. The plate angled below the positioner is to fit an extra stop/start setup so the switch is more accessible and follows the fence.

Any other Incra users see the sense in this?

 

[Adam9453]

It certainly looks like a better use of space but surely it's not as rigid and I would assume loses the ultra fine accuracy?

 

[shed9]

It certainly looks like a better use of space but surely it's not as rigid and I would assume loses the ultra fine accuracy?

The fence is rigid, however as I mentioned above I may redo the adapter for the fence for even more rigidity. The accuracy depends on the positioner relative to the lead screw which is unchanged in the new setup. I've used 10mm alloy in the adapter so there is no flex.

The fence gives me repeatable accuracy to the mm on the lock with further dialed in micro adjustablity to 0.05mm

 

[Adam9453]

Sounds good then, I thought the micro adjustability was finer than that though.
I don't have the incra system but have coveted it for a while.
My main concern was having enough space for it as the pictures I saw had the positioner in the centre of the fence with guide rails at front and back, it would therefore require a lot of dead space behind the positioner to utilise full width of cut

 

[DennisCA]

I wonder, is the incra a better system than the fence that came with the saw?

 

[shed9]

I wonder, is the incra a better system than the fence that came with the saw?

Yes, otherwise I would have left the old fence on.

The original Hammer fence is superb, don't get me wrong - it does what it's meant to. However the lock mechanism is a large knob (not the best) and not a lock down device. Also to get precise measurements, it's a case of bumping the fence to the closest mark on the scale by sight. I did contemplate fitting a Wixey WR700 to achieve more accurate cuts but this would still require bumping the fence into position. For the work I do I need consistent precision, to be able to get repeatable results between projects and that's exactly where the Incra shines. The lead screw and adjuster knob allows me to dial in an exact coordinate to the nearest 0.05mm every time.

 

[Adam9453]

I wish you were closer so I could see your setup in person. It sounds very good.
I get frustrated having to tap my fence into position, makes repeatable measurements very time consuming.
I probably find it more annoying as at work our guillotine is digitally controlled and moves as little as hundredths of a millimetre. It means super accurate, super fast repeat cuts
I'd love to get that control on my table saw

 

[shed9]

I wish you were closer so I could see your setup in person. It sounds very good.
I get frustrated having to tap my fence into position, makes repeatable measurements very time consuming.

Appreciate the distance aspect but you would be more than welcome to see it. I concur with the frustration. I know we are only working with wood here and I don't really need 0.005mm precision, however I need to work in increments of mm's so any additional accuracy is welcome.

A thing to note with all this, if you use your original fence, the cost of a 810mm positioner alone is under £250;

http://woodworkersworkshop.co.uk/epages ... INC_M-LS32

Coupled with around 1m of 45x90 alloy from here (about £20 per meter plus delivery);

http://www.aluminium-profile.co.uk/acat ... 92432.html

I paid under £30 for a 750mm offcut of 3/8" (4" x 4") angle alloy from Ebay. Yes there was some machining involved and it took a fair while, however most of this was initial setup. You could get away with less alloy as I built in a front panel under the positioner to house a switch housing later on. I also expect some extra costs with anodising (toyed with doing it myself but I'd rather be cutting wood) and obviously the NVR E-stop setup. You also need to factor in an router fence if you want to route on the backside of the TS fence.

Even if you account for a machine shop doing the work for you, this would probably still cost less than a complete Incra TS setup and you don't get the lost grey space typical with an Incra setup.

 

[Adam9453]

Thanks shed, if I can find an excuse to get over to Wales then I will certainly organise with you to check it out.
This conversation got me thinking and I googled motorised table saw fence. Tiger fence came up and looks on first glance like a very interesting bolt on motorised rip and/or crosscut fence system which is fully motorised and digitally controlled.
I haven't found the price yet but I have found a concern in terms of its accuracy, as it says it's only accurate to 0.7mm which I'm not certain I'd be happy to accept, let alone pay for.
I'm gonna look into linear actuators and speak to some friends about how to achieve a more accurate motorised fence

 

[pcb1962]

I'm gonna look into linear actuators and speak to some friends about how to achieve a more accurate motorised fence

Ballscrews and stepper motor as used in CNC metalworking machinery would be the way to go if you want ultimate accuracy and zero backlash

 

[shed9]

Adam9453 & pcb1962, I did (very breifly) contemplate ball screws with linear rails. I have a stack of them (plus steppers, drivers, etc) on a shelf from previous and current CNC router builds. I used to work with robotics and embedded processors as far back as the early 2000's and have assembled several CNC routers since so I have the technical ability

The real problem is the control process in that you would need a single axis controller and possibly a linear encoder depending on whether or not you want to trust the stepper count alone for positioning. Personally I wouldn't trust pushing wood through a TS with another system also having control of the process. It's often bad practice to incorporate CNC control of human operated equipment especially when cutting is involved. You would need to implement a mechanical lock down with an electrical disconnect of the system.

However, that's an awful lot of work for a TS fence which effectively would automate something that is already at arms length and readily accessible. I'm not sure the payback would be worth the effort.

There is something to be said for the simple hand operated mechanical lead screw based postioners. Less to go wrong, easier to implement and achieves the necessary precision.

I can see a use of CNC in high production areas but think it's an overkill for home and small business use. That said, I suspect many think the Incra system an overkill. I also suspect we will see a lot more automated TS products come on the market in the future.

Adam9453, have you seen Next Wave Automation's ready2rout products? They have an automated router fence, might be worth emailing them to ask if they have a TS product on the horizon?

http://shop.nextwaveautomation.com/shop ... itemid=130

 

[shed9]

For additional info, I've had some feedback from Incra themselves. They have clearly looked at this idea before - I think that was safe to assume anyhow.

Their response was as friendly and professional as always. I don't see them implementing anything similar anytime soon as they have more confidence in the rigidity of the positioner in the middle position - and I can see that in that my own fence could be more rigid than it is, although I think I have resolved this since with a longer adapter.

The beauty of using the aluminium alloy extrusion on my own fence is that it could be adapted to almost any mid to large table saw and it allows a mirror extrusion to be fitted on the rear of the saw to support the rear of the fence if you wanted more assurance of rigidity.

Anyone thinking of doing something similar, there is nothing bespoke about my setup and it could be transferred to another saw.

 

[Woodmatt]

Shed9

I have been considering getting the Inca positioner for some time but have never been able to see one in the flesh so to speak.Would it be possible to come and pay you a visit sometime in the next month or so and have a look at yours.I am only about 30 miles from you so would be a short hop.

Thanks
Matthew