Floating Drag Point

[rhotu]

New to this forum so please forgive me if this has already been asked.

Can anyone who has a floating drag point tool provide any of the following.

pressure exerted by the various springs (i.e. put scale on work table and compress to .2 in, results in grains,grams,oz or lbs).

what speeds and springs work best for what materials (granite, glass, aluminum, brass...)?

TIA

RT

[toddmaci]

Ralph,
I saw the results of this cutter at a shopbot camp. They were very good. I believe the guy that makes them is Russ Todd. Here is the link to his ebay store. I am not affiliated with the seller
http://cgi.ebay.com/Cut-Sign-Vinyl-Drag-Knife-Bit-for-CNC-Router-End-Mill_W0QQitemZ330276492979QQcmdZViewItemQQptZWoodw orking?hash=item330276492979&_trksid=p3911.c0.m14& _trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318. Not sure about the specs.

[Call-Tech]

If you are referring to a tool like the 2L Spring Loaded Engraving Tool? I own one and really like it. I'm afraid I don't have the technical answers you are looking for but I'll give you a few hands on things I have done.

When I first got my tool, I ordered it with all the springs and a both angles of diamond tools. I started etching mirrors first because the boxes of 12"x12" mirrors are cheap test pieces. I used Artcam pro to create toolpaths for simple vectors. Machine on vector and I just told it to cut .25" deep. The spring loaded tool has a travel of .4" so that worked perfect. I think I was using a speed of about 2-3" per second. I kept increasing spring pressure trying to make more defined engraving line and ultimately shattered one of the diamond tips. I talked to 2L and ordered more tips, they claim the lightest spring is the only one you need for most things. Everthing I have tried so far has been with my router off, just dragging tool around. I plan to try and spin tool at low speeds when I get some time to practice some more.

here is a link to posting where it is discussed in more detail, including some photos of finished work.
http://www.talkshopbot.com/forum/messages/312/30430.html

Here is a link to youtube video of larger version tool.
http://www.2linc.com/demo_spring_loaded_tool.htm

Here is a link to the tool I own.
http://www.2linc.com/engraving_mini.htm

-Fred

[knight_toolworks]

ceramic tiles took the heaviest spring and that broke the tip of mine too. glass needed more then the lightest spring.
I have been using a sharpened carbide bit for aluminum and it cuts deeper then the aluminum. I have not tried it yet on other materials.

[bryson]

Ralph, I use a diamond drag made by www.widgetworksunlimited.com (http://www.widgetworksunlimited.com). They do not come with different spring weights but I did run an unscientific test for you. At.2" the pressure measured just short of 2 pounds and at.5" it read just short of 6 pounds.
Hope this helps,
Bryson

[rhotu]

Bryson et al, thanks for responding. I am always interested in more data. If enough people respond with data on feed speeds and pressures for various materials I will put together a table and post it later on.

Thanks,

RT

[Call-Tech]

I am having trouble with breaking the diamond tipped drag bits. I have spoke with 2L, reduced my speed to practically nothing, added ramping moves and used the lightest spring and am still breaking these $25 bits without finishing a job.

Has anyone seen an alternative 3/16" 120 degree diamond drag bit?

or any other size? I'll modify tool or make adapter if needed.

-Fred