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View Full Version : Where to get T-slot clamps?



Sporqster
07-10-2005, 05:28 PM
Hello all -

I'm pretty new to the whole bench top CNC thing, but I recently got my Spectralight mill (basically a Taig in a box, from what I understand) running and I need some clamps to hold a larger workpiece.

I've found that double sided carpet tape is great for holding wood or Renshape, but it doesn't stick to machinable wax worth a poo. The only clamp I have that came with the mill will only hold about a 3" wide work piece. I need something that I can lock down to the XY table and hold a 5"x5" piece for me.

I'm new to this, so the only places I really knew too look for such t-slot clamps were at Harbor Freight and hardware stores, both places I kinda got blank stares from the clerk. Don't have a problem ordering on line, but don't know where to start looking.

I suppose I should just fabricate my own clamps, but I'm thinking that cutting tool steel with this little CNC might be asking a lot from it.

Thanks in advance!

wizard
07-10-2005, 10:28 PM
Here are a few suggestions:

First; read up a bit on milling and general machining. It is not uncommon to make special purpose clamps, fixtures and tooling. This may or may not fullfill your needs.

Second; maybe it should have been first is catalogs. If you can get access to Travers, McMaster-Carr, MSC, Grand Tool Supply, Little Machine Shop and whom ever else you can dig up! Visit your local distributors and hope that they have a reasonable attitude. And finally go to the model engineering shows like NAMES, Cabin Fever and what ever is local.

The reality is that your tooling expense will quickly out strip the cost of the machine itself. If you got time on your hands it would pay to make the stuff you need yourself. Especially for the smaller machines where finding mass produced tooling is a little harder. Larger machines have whole industries built around them so for example it is hard to beat the clamps available for a bridgeport.

Other things to consider are figuring out what your slot size is and getting yourself an assortment of cap screws, Nuts and hardwashers. With a bit of careful planning you should be able to cover much of your clamping needs with such bolts and a few home built clamps. Just make sure you cover yourself with designs that have the required strength. Shouldn,t be a big deal no a mill this size but the las thing your want are parts slipping arround while your CNC mill is happily running away.

Thanks
Dave

Nono
07-10-2005, 11:15 PM
If you have any carriage bolts around they work ok for hold downs, and you can find toggle clamps at rockler.com...

Sporqster
07-11-2005, 08:37 AM
If you have any carriage bolts around they work ok for hold downs, and you can find toggle clamps at rockler.com...

That's a good suggestion...

Actually for this one job, I'm getting by milling off the sides of the bottom of my workpiece so I have a 1/2" X 2" rib sticking out the bottom of the work piece that I can fit in the little clamp I have. Of course, this then makes the workpiece to tall that Z +.25 is right at the limit switch of the Z axis - and that's with only about 1/2" of my bit hanging out of the chuck! Looks like I'm going to be resetting my z axis a dozen times to get this thing milled, as it's fairly deep cavity and I'll need to get the tool down in the workpiece with no room for the chuck in there with it.

Oh unrelated question - I'm having trouble with my g-code generation on anything involving arcs. Prolly belongs in another category, but since I've got your attention, hear me out. I have just about nothing in the way of software, but would be willing to spend up to $200 or so if I could find the software that would do what I want.

I've been drawing out my tool path in AutoCAD 2000, saving as DXF, importing into a Mach 2 trial, converting to g-code, all on a computer not attached to the CNC and actually running TurboCNC to control the machine. The code Mach 2 writes is fine when it's streight lines, but it's doing something super funky when it the shape has an arc in it...

I'm using Catia because that's what I have at work to design the parts to begin with and check fit-up and such, but have no CAM plug in's for that... but I do have solid models of everything I want, if that helps.

What's some low overhead software (or better yet, a cheap plug in for AutoCAD) that will write g-code Turbo CNC understands?

Nono
07-11-2005, 12:24 PM
My understanding about autocad is very little, But I do know that when you import from autocad arcs become polylines and they do not always really connect to each other (autocad is a visual program). I use a very old copy of Smartcam, I can only import about 2000 line at a time from autocad then I re-draw or convert or re-arange everything to the right order/path and after that I convert it to G code. Sounds like you need a good cam program. As for the answer to that, not sure I would start im the software sections and find out.. I think visual mill is popular.... :)

jkeyser14
07-11-2005, 05:33 PM
My guess is that it has to do with the type of arc you are using. If you are cutting circles to create the arcs, or if you are using the 3 point arc button, some machines and software tend to dislike that. I know I've seen it cause problems on laser/waterjet machines. I use mach2 and autocad, but I use mastercam for all of my toolpaths. I've got a seat of CATIA myself, but haven't really used it.

Make sure you are using the arc command, don't cut circles and don't use the fillet command. If that doesn't work, try replacing the arcs with splines.

If you really can't figure it out, you could also try posting at http://groups.yahoo.com/group/mach1mach2cnc
The author of the software (A guy named Art) is very quick to reply to posts there and help people.

wizard
07-12-2005, 12:22 AM
Not to reply agian but this may be of interest. I happened to leaf through on of the catalogs that recently landed in my mailbox. This is a sales flier from Grand Tool Supply, they have two pages of clamps, tee-nuts and similar stuff on sale. Most of it likely to be of lmited use on a Taig.

Further I've never done business with these guys so I have no experience to relate on their service.

Dave

cbr_speedster
05-12-2018, 10:20 PM
SmartCAM huh? I really liked using SmartCAM back in the day. I have Version 11.5 but it won't work past Windows XP so switched to Esprit....

Fastest1
05-13-2018, 01:25 PM
All the Spectralight's I have ever seen were Sherline based not Taig.