Don't try manual hold downs, LOL

After some “challenges” with importing and then assembling my x-carve, today I finally did my first cut on a piece of material, my name and an easel squiggle on a bit of MDF. Sadly my very shoddy attempt at a hold down came off shortly into the cut, but to save the day I held it down with my fingers for the next 30 minutes. All went well until the finish, the Easel screen said 100% but the machine was still going, and while I was looking for clues on the screen the spindle suddenly shot back to the start point, where my thumb was safely out of the cut path, but right on the home spot. Ouch. Just a little blood, and apart from the mess at the top of the “M” before I grabbed the MDF, I am very pleasantly surprised. One of the lower X axis V wheels came loose and actually fell off around the 75% point, but it didn’t seem to hold the machine back at all.

I am very pleased that the machine is doing what I had hoped it would. Unfortunately ordering ready made clamps or getting 3-d printed is not an option here, so I’ll be looking through the forum for some better ideas. I’ll also reattach the spare v-wheel before the next try.

i use 3 or 4 small pieces of wood and screw it down(2 inches by 3 inches 3/4 thick), this works well for me, also 2 sided tape is an option.

I use a wooden block, about 4" long by 1 3/4" wide by 1/2 " thick with a 1/4" slot routed down the center coming short of the ends by about 3/4".

This works to hold the work piece (piece) vertically if i place it at an angle with one end on the piece and the other on the table and held in place with a bolt in the center to the waste board inserts. If needed, I can use a longer bolt, and a piece of scrap under the end not holding the piece this allows working with thicker materials.

I can also simply butt it/them up against the side of the piece and apply tension with a cam clamp on the opposite side.

They are cheap and easy to produce, versatile, and replaceable as needed.

For simple jobs like this, double sided tape works really well. Test it first though, some tapes can tear the surface off MDF…

I am using my machine to engrave cutting boards right now. My collection of parts for hold downs just came in today, so for now I have just been using Hot Glue to hold them down. These are Bamboo cutting boards. Typically I would use doublesided carpet tape. In this situation I found that the tape did not want to stick to the bamboo allowing the board to slide. So the hot glue method worked great.

I recommend when using Hot Glue, use it Sparingly though. A little goes a long way. Too much could cause the workpiece to be hard to break loose or tear a chunk out of the MDF when removing. I use a paint scraper to slide in under the board to pop it loose.

FYI. Coat your MDF with shellac sanding sealer or a Poly, this will help keep the board from tearing out.

my first project with my machine was to make clamps.

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I think sometimes we take these small cnc machines for granted they are every bit as dangerous as a table saw

Glad your okay

As others have said, I’m glad you didn’t get hurt worse. I think you’ve learned an important lesson, when the spindle is running body parts don’t go in the cutting envelope, period. You can stick vacuum cleaner ends in there, and if you absolutely need to, a push stick can be used, but nothing that can bleed.

I didn’t have clamps to begin with, and I planed on one of my first projects being making some. But I started using flooring tape, and I’ve kept using it, since it has been working so well. It gets stuck on the to be cut wood first, then placed on the waste board. When it gets popped off the waste board with a paint scraper no residue has stayed behind on it. And the tape can be pealed off the cut wood easily as well.

Good luck, and keep cutting (just not body parts),

Steven

Clamps are cheap, easy to make and use. I also suggest parallels under the work piece so that the waste board stays untouched.
I treat this X Carve the same as I would a full sized metal working mill. It can do a lot of damage in a very short time.
I made my own after a malfunction chewed through the first ones from Inventables.

Thank you everyone for suggestions and measurements. I don’t know if I can get double sided tape here, so I’ll try making some clamps today, or try hot glue.

Thanks for the photo JDM, In the comma shaped clamps on the right, what are the holes for?

so I can use them sideways like a cam

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I see, nice.


I made and used these today, I have to tighten up my belts and v-wheels, another one fell off today, but it didn’t affect the final product.

i’ve asked the inventables folks to put a checkbox that allows the user to set whether the machine should return to home after it is done. I’ve also run into problems with it running into a clamp that I had to place after zeroing the machine. In this case, it was your finger.

One of the things I learned is that almost all of my work-holding problems happen when a piece slips sideways… not up or down. Double sided tape… vertical clamps… they are all just approaching the problem using friction. Horizontal clamps, or blocks of wood around the sides… that is what you really want. All the piece has to do is NOT slide! I mean, you want some vertical pressure to make sure it doesn’t come out, but the main thing is keep the piece from sliding. I designed and printed my own horizontal clamps for my machine and they are what I use quite a bit. One advantage of these over cam clamps is that they don’t put pressure on the sides… so if you do a contour cut to cut out a part all the way through the stock, your stock won’t collapse and clamp on to the bit and potentially cause a huge problem. You just need to keep the stock from moving, you don’t really need horizontal pressure.

Anyhow, these are the ones I made: http://www.thingiverse.com/thing:818842

And Inventables… add that check box!!! People are bleeding over here!!! :smile:

@FrankGraffagnino

How flat are 3d prints when they are finished I mean are they cnc flat? Within .0001 tolerance of being flat?

no, not usually… there is always some warping due to thermal effects and also there are little ridge lines along the extruder paths. for stuff like this though, that doesn’t matter.

Rockler makes a set of horizontal stops, of different styles.

The small ones are easy to make.

You wouldn’t believe how fast whirling edged steel can take a chunk out of a finger. See ya in the fingertip mod section! hahaha