[gio666]

https://www.youtube.com/watch?v=T2ut...ature=youtu.be

[gio666]

https://www.youtube.com/watch?v=khDZ...ature=youtu.be

[gio666]

https://www.youtube.com/watch?v=9SG_6aKASUU

[JohninOttawa]

Good morning all.

Finally getting some time to use the Raptor and on the inevitable learning curve. Last night was double-sided milling on 1/2" acrylic.

The good news is that the repeatability of the machine is outstanding. Using a mirrored top and bottom drawing and some locating holes for screwing the plate down worked like a charm.

One issue I had was unexpected flex at a far edge of a profile cut. I thought I had everything held down tight but the spiral bit managed to pull the sheet up a bit during the cut and roughed up my edge. My fault for not predicting the flex in the plastic well enough. Didn't destroy the piece or the bit, but the noise sure got my attention....

So I have two questions coming out of this. The first was spindle speed. I figured that, when cutting plastic, slow is better to avoid melting. I'm using a three flute carbide 1/4" spiral bit (up cut, which of course added to the problem). The cut was otherwise smooth, but I'm wondering if a different speed would reduce or worsen the flex issue. Or is the solution just to really reduce the depth of each pass? I don't know if this just delays the inevitable when the profile cut reaches the bottom of the material.

My second question is how to clamp or otherwise hold down cuts on this kind of material. I decided not to go with hold downs as the material is so smooth I figured it would just move. Screwing through the surface only works to a point. Once I start cutting out holes and shapes, either I need to put a lot of holes into my work or do something different. I can place bridges into the work, but I've heard mixed reviews. What works for you folks?

I am thinking of building a vacuum table, but that's going to have to wait for a few months.

Thanks for your advice!

-John

[gio666]

Good morning all.

Finally getting some time to use the Raptor and on the inevitable learning curve. Last night was double-sided milling on 1/2" acrylic.

The good news is that the repeatability of the machine is outstanding. Using a mirrored top and bottom drawing and some locating holes for screwing the plate down worked like a charm.

One issue I had was unexpected flex at a far edge of a profile cut. I thought I had everything held down tight but the spiral bit managed to pull the sheet up a bit during the cut and roughed up my edge. My fault for not predicting the flex in the plastic well enough. Didn't destroy the piece or the bit, but the noise sure got my attention....

So I have two questions coming out of this. The first was spindle speed. I figured that, when cutting plastic, slow is better to avoid melting. I'm using a three flute carbide 1/4" spiral bit (up cut, which of course added to the problem). The cut was otherwise smooth, but I'm wondering if a different speed would reduce or worsen the flex issue. Or is the solution just to really reduce the depth of each pass? I don't know if this just delays the inevitable when the profile cut reaches the bottom of the material.

My second question is how to clamp or otherwise hold down cuts on this kind of material. I decided not to go with hold downs as the material is so smooth I figured it would just move. Screwing through the surface only works to a point. Once I start cutting out holes and shapes, either I need to put a lot of holes into my work or do something different. I can place bridges into the work, but I've heard mixed reviews. What works for you folks?

I am thinking of building a vacuum table, but that's going to have to wait for a few months.

Thanks for your advice!

-John

Vacuum fixture is best most times , but depends on how small part gets when cut out and size of pump

[gio666]

On 40x48 Predator

Here are some test cuts. I'm trying to leave little "islands" that will show how round the cuts really are.
And as well as this worked, it also bears witness to the smoothness & accuracy of the spindle!
To better put these little pins in perspective...

I can't believe I was cutting an "island" .010" diameter that was 5X that deep.

[mike2768]

Good morning all.

Finally getting some time to use the Raptor and on the inevitable learning curve. Last night was double-sided milling on 1/2" acrylic.

The good news is that the repeatability of the machine is outstanding. Using a mirrored top and bottom drawing and some locating holes for screwing the plate down worked like a charm.

One issue I had was unexpected flex at a far edge of a profile cut. I thought I had everything held down tight but the spiral bit managed to pull the sheet up a bit during the cut and roughed up my edge. My fault for not predicting the flex in the plastic well enough. Didn't destroy the piece or the bit, but the noise sure got my attention....

So I have two questions coming out of this. The first was spindle speed. I figured that, when cutting plastic, slow is better to avoid melting. I'm using a three flute carbide 1/4" spiral bit (up cut, which of course added to the problem). The cut was otherwise smooth, but I'm wondering if a different speed would reduce or worsen the flex issue. Or is the solution just to really reduce the depth of each pass? I don't know if this just delays the inevitable when the profile cut reaches the bottom of the material.

My second question is how to clamp or otherwise hold down cuts on this kind of material. I decided not to go with hold downs as the material is so smooth I figured it would just move. Screwing through the surface only works to a point. Once I start cutting out holes and shapes, either I need to put a lot of holes into my work or do something different. I can place bridges into the work, but I've heard mixed reviews. What works for you folks?

I am thinking of building a vacuum table, but that's going to have to wait for a few months.

Thanks for your advice!

-John

I have an answer to your question regarding cutting feeds. First is get yourself a single flute cutter. They work awesome, I've used both the 1/8" and 1/4" ones. When I use them I cut around the 60ipm plus range at about 15000-18000 rpm they work amazing. I have a few videos on YouTube, if you want to look search "mike2768"

[JohninOttawa]

Thanks for the suggestions! I'm checking out options for o flute bits. Any recommended suppliers in the Toronto/Ottawa areas?

Vacuum table looks like a worthy project for sure. In the mean time, I found a place that sells 1/4-20 hardware made of plastic, so I will try using that for clamping as well.

I was a bit concerned about screwing the work down too close to a cut line, for fear that I miscalculated and the bit contacted the hold down. So far, no such unexpected behaviour, and I think the plastic bolts might avoid serious consequences in the event of a brush with a bit.

Anyone have strong feelings about dimar vs onsrud vs Freud (or better suggestion) for single flute bits?

Cheers
-John

[ihavenofish]

plastic bolts wont be strong enough to clamp the work most likely.

if you end up hitting a bolt with a small cutter, the bit will break, or be cut. s you lose a bit. not much else will come of it.

if your using a large cutter, the machine could stall, and then slightly worse things could happen - possibly damaging the spindle. generally things are 99% safe, but if something is sketchy, just keep a hand on the e stop

[JohninOttawa]

I'll have to check out the strength of these things first, thanks for the heads up.

I did get the dishing bit at LVT. Once again, I can't get my router low enough to contact the work, even with an inch and half additional material on my table. (Hitachi M12VC). I'm wondering if the best way forward is just to shift the entire Z axis down using the alternate row of holes. Has anyone tried this? Anything I have to do differently to ensure proper alignment?

John

[ihavenofish]

usually you dont want to move the z down.

what spindle do you have? on the tekno spindle, the mounting plate was low enough to hit the spindle nose on the table. the clamps for a hand router may perhaps not be low enough.

[JohninOttawa]

It's a Hitachi M12VC, with an older mounting plate, so it was seriously high. I was able to install the mounting plate upside down and get another inch of travel, but for most bits, it's still 1.5 to 2 inches above the table top.

I realise a real spindle would be better, and perhaps will be an upgrade, but as I had two Hitachis already, it seemed a no-brainer. Performance seems smooth and I will install SuperPID on one shortly, which will give me lower RPM at torque. My only issue (so far) seems to be bottom end. I tried to talk George into a custom Z-plate, but it doesn't sound practical, due to machining costs for a one-off and possible rigidity issues.

I wonder how many Hitachis and other hand routers are running on Xzero setups. Maybe everyone has the same travel issue. If so, is there a market for a run of longer mounting plates, maybe defray the cost? Maybe there's a way to estimate the amount of additional flex the longer mount would have and whether it would affect accuracy. Maybe the runout in these routers is more than the amount of error introduced by flex.

John

[tinmancarving]

John, what about making a sub plate that bolts between the z plate and motor bracket. It would only need to be 5/8 -1" think. Make it a little longer to get you that correct mount position. It wouldn't be difficult to design and make. If you start with Mic6 plate it would already have parallel faces. That just leaves shooting holes through it.
Rob



Sent from my iPhone using Tapatalk

[JohninOttawa]

Hi rob. I had wondered if that would be a fix, but I think the issue with extending the original Z plate would affect a sub-plate too, that is you have a section that is not supported below the lower edge of the linear bearing. That's why I thought it would be better to go with the full thickness of the Z plate, as extending it would also extend the thick vertical 'columns' and get strength.

I've tried to attach a pdf of what I think the modified plate would look like. I understand it is a pricey thing to produce though.

-John

[gio666]

Hi rob. I had wondered if that would be a fix, but I think the issue with extending the original Z plate would affect a sub-plate too, that is you have a section that is not supported below the lower edge of the linear bearing. That's why I thought it would be better to go with the full thickness of the Z plate, as extending it would also extend the thick vertical 'columns' and get strength.

I've tried to attach a pdf of what I think the modified plate would look like. I understand it is a pricey thing to produce though.

-John

Just lower the Z axis or use board underneath , Just in till you get a larger spindle? That plate has to be machined perfect or will cause a lot of problems for ballscrew on Y axis
There is critical dimensions on back of plate

[JohninOttawa]

Thanks George.

I can lower the axis, but before I do that, I want to make sure I can align it properly. It's pretty easy now with the axis flush with the bottom of the linear bearing. I lose that reference at the lower setting. What's a good alignment technique when the axis is lower?

John.

[gio666]

Yes , you can go off side of block, better to use gauge and tram the spindle

https://www.youtube.com/watch?v=0-D1gNYPi3A

[JohninOttawa]

Tramming looks like a good idea regardless.

Any experience with the Pro Tram? Has anyone tried making something similar? Looks to me like it should be easy, but you have to have everything dead on to begin with, sort of a catch-22.

-John

[Padrino]

Yes , you can go off side of block, better to use gauge and tram the spindle

https://www.youtube.com/watch?v=0-D1gNYPi3A

This is great. Thanks for posting this George.

[gio666]

Raptor Green