Need Help!- anyone built a Tangential Knife

[Momentz]

HI
i am in the picture framing business and i am wanting to build a mat cutter, i have already bought than plans for a joes 4x4 hybrid and in the process of building that, but i have been thing surely its not that hard to put a Tangential Knife on the z axis so it does 90deg cuts and 45deg cuts aswell, has anyone built one or does anyone know where you can buy just the cutter? i did a google search but with not much luck
thanks

[Momentz]

wow put of 161,616 members no one can answer my questions or there just not interested, i have only posted 6 threads and only one has a reply, i guess this forum isnt that great

[otto_pjm]

Perhaps the other 80 people who've looked at your post don't know what a tangential knife is either, I checked out your thread because I've never heard of it. Would it be like a drag cutter? If so maybe check the threads on vinyl sign cutting and the like. I wouldn't be so quick to blame the forums.

Good luck with the Joe's it's a great design, are you going to go with the R&P or Leadscrews? I'll look for your build on Joe's as well, try your question there as well if you haven't it tends to be very active.

Pete

[Momentz]

hi
i will be doing the R&P version it looks easier and people seem to upgrading to it, i havnt read anypost about people upgrading to the leadscrew

[gfc62]

I'm curious about adding a tangential knife to my Joes hybrid but haven't done anything about it.

Have you looked at this video?
YouTube- Tangential Knife
Or read:
http://www.machsupport.com/forum/ind...?topic=13082.0

Looks like they used a stepper motor where the router would be on the Z axis. A knife holder on the stepper shaft rotates to stay on the cut line.

Hope this is of some small help. What's your user name on Joe's forum?

Gordon

[Momentz]

hi
my user name is the same here aswell "momentz". i have seen that video, whe i get my joes 4x4 complete i will buy an extra stepper motor and start trialing but that is a long time away. if you could come up with the design beofre i do that would be great and then you could tell me how to do it

[lovebugjunkie]

http://www.rockcliffmachine.com/prod...products_id=89

[gfc62]

Originally Posted by lovebugjunkie http://www.rockcliffmachine.com/prod...products_id=89

That's a drag knife, not the tangential knife he's asking about.

[gfc62]

Maybe we can just get lovebugjunkie to do it for both of us ;^)

[fatal-exception]

It seems that there are a few companies out there that sell tangential cutting heads. AXYZ is one, there are others on google.

I see there's an easy way to get Mach3 to do the tangential control, just a single button on the settings screen and adding another motor to the ports and pins setup page.

I think I will take on the challenge of designing a cutting head. I'm thinking NEMA23 stepper motor coupled to the knife shaft with pulleys and a belt. A simple way to mount the knife, possibly some sort of collet system to allow different knives to be used?

Would it be beneficial to have the knife reciprocate up and down? I see that there are oscillating cutters and tangential cutters, but is there such a thing as an oscillating/tangential cutter?

Thanks,
Paul

[gfc62]

Have you seen this video as well?

http://www.youtube.com/v/anspATAZZQA

That looks like a simple design for a knifeholder. Just some aluminum bar stock and a clamping plate for the blade. I could cob that together on the mini mill and lathe.

I don't have any experience using a CNC cutter to cut mats, do you think the cut needs to be done in one pass or can it be done with multiple passes as you would with a router?

At what point does an oscillating knife become necessary? Is that only for cutting thicker or denser materials?

[gfc62]

Originally Posted by fatal-exception It seems that there are a few companies out there that sell tangential cutting heads. AXYZ is one, there are others on google.

I'm guessing these are out of my budget, have you priced any?

I see there's an easy way to get Mach3 to do the tangential control, just a single button on the settings screen and adding another motor to the ports and pins setup page. I think I will take on the challenge of designing a cutting head. I'm thinking NEMA23 stepper motor coupled to the knife shaft with pulleys and a belt.

Do you think the pulleys are needed for gear reduction? Or is that for some other purpose? I'd think a stepper motor of the size you're thinking would have enough torque as is.

A simple way to mount the knife, possibly some sort of collet system to allow different knives to be used?

Are we talking about xacto type blades here? Or something different?

Would it be beneficial to have the knife reciprocate up and down? I see that there are oscillating cutters and tangential cutters, but is there such a thing as an oscillating/tangential cutter?

I'm pretty sure all oscillating cutters are tangential.

Would you try to oscillate the entire motor/knifeholder assembly? Or just the knife?

Thanks, Paul