Blick Leatherhead

[Ken Lago]

What do you mean with sweeping motion?

[Dan R.]

The COMES head has a gear mechanism that sweeps the brushes as they rotate. It basically rocks them back and forth as the head spins. This creates a sweeping motion. This motion is the difference between a dedicated machine, with a COMES head and a re tasked cnc using a Blick leathering head. To ask a cnc to do as well is unrealistic. Hopefully, the cnc can become economically viable in some situations.

The flicking of the sweeping motion is key. That flick is what removes the material, not just dragging over the top. The flick actually digs a bit. The changing contact points between the stone and the brush means more tension and material removal. Try using a broom without the flick at the end of a stroke. Far less effective than with a flick at the end.

A rotatary only unit will be limited by the physics of no flick, thus generating less pressure and ability to remove material.

[Angel]

Removing material is not an issue, in fact with a 36 grit it is using VERY little pressure. Maybe the "flick" is what the difference is with the trail marks.
I've been using the 5" single brushes up to 400 but I'm sure I could stop at 120 or 200

[Dan R.]

Angel, are you getting circles scratch marks? Is this what mean by trail marks?

I talked to 2 people and they said they had an issue breaking the polish with the 36 diamond wire brush. I thought they must be using a different brush. We use the 36 or the 46 or the 60 diamond wire brush as a first step to remove the polish.

after the diamond wire brush, try a 60 Filliflex (resin) brush then a 120 or 220 resin. We only run one cycle of diamond wire brushes.

[Angel]

No scratches, when you look across the surface you can see the pattern the machine used. I've tried straight, curved patterns and it just didn't matter.
There is no wobble at all in the head. As far as weight for the head it actually weighs less than a double hogger used for bull nosing.

[Angel]

The first sample I did I used 36,46,60,120,200,400. Waaaaay overkill

[Angel]

Oh yea I wasn't even pulling 3 amps so the machine wasn't being pushed at all

[Dan R.]

How do your brushes wear? Our Frickert brushes wear out from the outside in.

So, you are seeing a pattern of the cycle. Do you run different directional passes with in a cycle? For us, a cycle consists of a perimeter pass, a vertical overlapping pass, a horizontal overlapping pass and a 18" zig zag overlapping pass. Never had a an issue with trails.

[Dan R.]

Angel are you using the bricks or the round brushes with a 5/8"/11 thread? How many brushes on the head at once?

Try a 36 wire, 60 resin 120r, and 220r

[Angel]

round brushes (tenax) not bricks. They are snail lock, single head.

[Dan R.]

A Blick head I'll cover much more area for you.

[GuyboR]

round brushes (tenax) not bricks. They are snail lock, single head.

I don't think you will be able to get away from trail marks using the single pad head.

We use the tenax 4 pad unit. The only time we have had trail marks is when we tried breaking the shine with a calibration wheel.

Robbie was showing me the new bricks that tenax has for breaking the shine. He said it is the cat's meow....translation for you way southerner....they are GREAT. I have a photo, but it's at the office.

[flav]

In my limited experience, there are a few critical and distinct processes in how we leather a slab:

step 1 - breaking polish: for this we use a 10" segmented metal diamond tool with 150 grit (or 50 grit if necessary but needs to be followed by 150 grit to remove scratches)
http://www.granquartz.ca/p-1613-kenmabe ... 250mm.aspx
I am sure something similar to this is available in the frankfurt style for the blick leather head like so:
http://www.granquartz.ca/p-1099-frankfu ... ricks.aspx
Sometimes you can break polish with a 36 grit diamond brush, but other times you just can't in a feasible time frame (eg. resined black pearl granite).

step 2 - depth of leathering: for this we use a 36 grit diamond brush in either 1 pass or 2 passes. Also critical is that this step removes the scratches from the previous step (hasn't been a problem for me yet). I don't think you can use filliflex brushes in this step only diamond brushes. I am considering getting a 24 grit diamond brush to get a bit better depth into the stone.

step 3 - achieving the colour or shine of the finish that you want. We use 120 grit dimaond brush, 320 grit diamond brush, then 240 silicone carbide brush. I think the Filliflex are in this category of finishing. Haven't had an issue with scratch marks or trails but I am still using circular motions on the cnc.

Oh yea I wasn't even pulling 3 amps so the machine wasn't being pushed at all

The amps or hp reading on the cnc can be misleading since it is a measure of energy and at something like 400-800 rpm, the energy required for that rpm is very low. The issue is torque and stalling the spindle. My cnc shows around 0.2 to 0.6 HP with the brushes since I backed off the pressure (thanks Dan ).

Would it be possible to mount a COMES head on a cnc?

Not easily. The COMES head requires the top portion to be bolted onto a fixed head and cannot be allow to spin freely or else the gears won't work.

Robbie was showing me the new bricks that tenax has for breaking the shine. He said it is the cat's meow....translation for you way southerner....they are GREAT. I have a photo, but it's at the office.

If it breaks polish quickly without leaving deep scratches then I am interested in this as well.

round brushes (tenax) not bricks. They are snail lock, single head.

I think you should really look at the Blick Leatherhead or the Tenax frankfurt plate or some other 10" to 14" spring loaded contraption if you are planning on leathering slabs in any reasonable time frame.

[Dan R.]

The 24 grit may not give you any deeper leather, just deeper scratches. This calling for an extra step to remove. Try running the 36 brush one more cycle. It will be rougher than a single cycle.

[granitehouseuk]

I want to buy a Leatherhead , please can any of you guys advise me if they are good ?

Should I buy it with the snail locks ?

If yes then what size 4" , 5" , 6".

What type of brushes should i be using.

Unfortunately in the UK we do not have anyone who can advise us.

Please help.


Arif

[Dan R.]

What type of machine are you running?

Do you want to do full slabs or cut parts?

[granitehouseuk]

Hi Dan

Thanks for getting back to me. We have a Breton NC 300 K26

we also have a Breton 5 axis nc550 optima saw

we also use a Cobalm CNC 3000 idea top.

Hope this helps.

[granitehouseuk]

Sorry Dan,

Forgot to mention that we want to do both .

[Dan R.]

The Blick head will give some decent results, at a slow out put.

For the Blick head, I would suggest the snail lock brushes, so you can use the same brushes on your hand tools for the edges. The bricks will add no advantages over the snail locals with no COMBS head. You can then inventory one style of brushes for all your needs.

[granitehouseuk]

Hi Dan

Thank you for all your help.