New Large Slab Levelling/Milling Table

[cemannion]

Just a thought,
we flatten slabs routinely with a 3000x2000 cnc router with a 63mm tipped cutter which works really well. I'm noyt touting for business but I suggest that you may have a local equivalent who can do the work normally around 60 a slab both sides, which is ready for sanding with 120 grit.
I like what you are proposing though
chris

 

[worn thumbs]

It looks like an epic amount of work (and mess to clear up) but you will have the satisfaction of achieving the outcome you seek.I won't mention a No5 either as it would create another large pile of shavings and some bulging biceps too.I will mention that a man with a large CNC router could skim such a slab in six or seven minutes.

 

[Jameshow]

It looks like an epic amount of work (and mess to clear up) but you will have the satisfaction of achieving the outcome you seek.I won't mention a No5 either as it would create another large pile of shavings and some bulging biceps too.I will mention that a man with a large CNC router could skim such a slab in six or seven minutes.

No 5 1/2 or 6 would be better still?!

 

[MF1000]

Just a thought,
we flatten slabs routinely with a 3000x2000 cnc router with a 63mm tipped cutter which works really well. I'm noyt touting for business but I suggest that you may have a local equivalent who can do the work normally around 60 a slab both sides, which is ready for sanding with 120 grit.
I like what you are proposing though
chris

It’s the satisfaction etc of producing the finished item with my own efforts that’s driving this ……I’ve easily milled a 34” dia beech cookie cut before but this is taking it to a whole new level. I use a 37mm dia cutter with 3x replaceable cutters in my router at its slowest rpm, then it’s out with a monster belt sander before moving on to orbital and had sanding etc.

 

[curryjunkie]

marius hornberger on youtube has a great setup for slab flattening, his original video on it uses independent rails and bearers directly on the floor, he uses a string method to get them parralell and in plane with the rails, simple and a lot less material to store between uses

 

[curryjunkie]

heres another video where he improves on the design by adding levelling feet to the cross beams, i love how compact this is when broken down for storage

 

[MF1000]

Struggling with the weather to make much progress on the build but inbetween showers and my day job taking me to France last week etc I’ve been able to start the build on the router sled…hope to get it finished this weekend.

 

[MF1000]

The fine weather yesterday & today has allowed me to move the build on to a close to finished point.

i started with clamping the cls to each side of the osb bed and drilling the 8 of 10mm holes per side for the coach bolts (countersunk in) to attach them. One drilled out and coach bolts fitted the 20mm linear rails were fixed to each cls with 5 x 50 mm screws

as suggested on this thread I then checked the levels with cross strings


It was within 1mm


the rails are offset to allow a ‘landing stage ‘ fir the router sled/rails to assist fitting them onto each side rail.

The router is fitted onto a A4 piece of 10mm acrylic suspended by coach bolts hanging from 10mm alu plates attached to each linear bearing











tried a smal 400mm sq slab of beech on the setup to check it’s alignment etc




Very pleased with the machined finish and the thickness variation was within 0.5mm too

The acid test of course is one of my 2000x700mm slabs

 

[MF1000]

The main issue to address now is the vibration from the router and large cutter head combo is very efficient at loosening the screws on the linear bearings etc ….bottle of thread lock needed I feel.

 

[cemannion]

The main issue to address now is the vibration from the router and large cutter head combo is very efficient at loosening the screws on the linear bearings etc ….bottle of thread lock needed I feel.

Nice

 

[MF1000]

Thread lock was applied to all of the screws last weekend …..then rain stopped play

Milled off my the larger of my two pieces of sequoia yesterday ….works really well. Next step is to fit a curtain around 3 sides of the acrylic with a vac point.

Managed to snaffle an off cut of clear strip curtain used in food factories….think it will work really well.

 

[MF1000]

Quick pic of the mill in use today …very easy to use and much faster than the mdf sled

 

[alex robinson]

Quick pic of the mill in use today …very easy to use and much faster than the mdf sled View attachment 175665View attachment 175666

I really like the look of your setup. Very impressive!

I too am considering upgrading from a wooden sled made out of scrap. What diameter are your linear bearings?

When it comes to using it, do you still need to hold the the router steady to prevent dig ins? I see various videos on youtube with people pushing it back and forth with 1 hand. This certainly isn't my experience with the wooden one - I need to hold on for dear life to keep it steady, otherwise there is a big bang and a huge gouge out of the piece being flattened! I have a 2 1/2 inch cutter that is brilliantly quick, but can get a bit "interesting" on end grain pieces with variable hardness.

 

[SkinnyB]

I made one using a Triton Wide Planer some time ago. Much quicker/better results. Harder to make though.

Video:


Build thread:
(Final design at end)
https://www.ukworkshop.co.uk/threads/my-portable-wide-slab-flattening-jig.117420/

 

[MF1000]

I really like the look of your setup. Very impressive!

I too am considering upgrading from a wooden sled made out of scrap. What diameter are your linear bearings?

When it comes to using it, do you still need to hold the the router steady to prevent dig ins? I see various videos on youtube with people pushing it back and forth with 1 hand. This certainly isn't my experience with the wooden one - I need to hold on for dear life to keep it steady, otherwise there is a big bang and a huge gouge out of the piece being flattened! I have a 2 1/2 inch cutter that is brilliantly quick, but can get a bit "interesting" on end grain pieces with variable hardness.

The rails are 20mm

As with any milling of wood care needs to be taken on changes of grain and soft/hard spots etc. I have a spill board cutter with replaceable cutter tips which gives a good cut and only ever try to take 1mm per pass….this seems to reduce the rip outs …..but it does still happen.

Not done any end grain milling with it yet. If you were milking a end grain chopping board etc I’d probably go down to 0.5mm per pass and have sacrificial strips around the edges too.

 

[alex robinson]

The rails are 20mm

As with any milling of wood care needs to be taken on changes of grain and soft/hard spots etc. I have a spill board cutter with replaceable cutter tips which gives a good cut and only ever try to take 1mm per pass….this seems to reduce the rip outs …..but it does still happen.

Not done any end grain milling with it yet. If you were milking a end grain chopping board etc I’d probably go down to 0.5mm per pass and have sacrificial strips around the edges too.

It isn't so much tear out that I am worried about - I have a 2 + 2 bit with inserts on the sides, so thicker cuts aren't a problem. It is the keeping the router perfectly flat that I find annoying with the wooden version. Do you find your setup stops any play and keeps the spindle completely vertical, or does that still have to be done by hand?

Thanks for the details about the rail thickness - they seem to come in a whole range of sizes.

 

[MF1000]

The sled doesn’t need a vice like grip and with carefull adjustment of the bolts holding the router to the linear bearings you can get the cutter ‘level’ ….but there will always be a small level of play in the bearings so you will see a slight striping effect from the milling cutter…….easily removed during sanding after flattening.

 

[alex robinson]

The sled doesn’t need a vice like grip and with carefull adjustment of the bolts holding the router to the linear bearings you can get the cutter ‘level’ ….but there will always be a small level of play in the bearings so you will see a slight striping effect from the milling cutter…….easily removed during sanding after flattening.

That is music to my ears! Found it very frustrating that with the old set up there didn't seem any difference in finish or stress levels if I was taking 1 mm or nearly 10.

 

[Jacob]

Just dropped into this thread by chance.
Don't see why you need a table at all. The workpieces could be sitting on saw stools and the "frame" for the router/hand-planer/chain-saw/whatever, attached to the sides of the workpiece or otherwise located.
Variations of the way they slab a tree-trunk with a chain saw and a ladder, or @SkinnyB 's set-up above.