Inventables Community Forum

Workpiece hold down options?

I have been racking my brain and for ideas of a good hold down option for my work pieces. I am not getting the MDF wasteboard from inventables and will be putting my own MDF sheet. I have considered a benchdogs idea, running some T-track with clamps but my concern is the height of the clamps and them possibly hitting the gantry.

I know its possible to use double stick/ carpet tape or screw the piece directly to the wasteboard but that does not seem very practical. Just wanted to throw a line out there and see what other people have in mind? Any help would be great!

there are loads of utube videos for vacuum table builds, google search for it, looks like the way to go for holding the material, no way to damage anything, no taping and you probably already have vacuum for removing cuttings in place already.

Have a look on the user uploaded projects there are some hold downs there you can cut out on the X-Carve, i have been using them and they work well.

You would just need to use a different bolt if using T Track, another option is there are some specialised router bits that can cut the T Track in the wood, better to use plywood for that i have used them for hold downs on drill presses etc and they work well and you wont have the worry of hitting the aluminium t Track on through cuts.

Also a Vaccum table could be another good way to do it.

Bench dogs will work if you use the low ones like the veritas ones but you would probably need to raise the machine up as they protrude out through the bottom of the wood by about 40mm or so depending on the brand you get.

This method seems interesting and effective however it seems rather expensive of a venture to buy the vacuum pump and if you use a shopvac I can only imagine the extra noise.

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Do a search on google for conversion of a compressor for a freezer, air-conditioner or dehumidifier. This could be a cheaper option for the vacuum pump, if you have one you are not using, or get one from a scrap dealer.
The option of a vacuum cleaner in an enclosure would work as well, if properly insulated for noise reduction.

There’s a page on this on the Shapeoko wiki: http://www.shapeoko.com/wiki/index.php/Workholding

my two cents, in one cent chunks :wink:

  1. Keep in mind that there is barely any vertical force on the material, so “hold-down” is really “hold-side-to-side”. The implication of this is that you can do a lot by just pushing the material sideways from two opposite directions, without actually applying downward force. I’ve seen some cool t-slot + cam clamps that use this technique and they have basically zero vertical height to worry about clearing (usually less than the material itself).

  2. I’ve used double stick tape with a lot of success. The key I think is finding the right stuff. @SamAlaimo bought the stuff that I used. I don’t know what kind it was, but she did say “It is the only $50 roll of double sided tape on amazon”. It is a big roll :stuck_out_tongue_winking_eye:

I was thinking about taking an off-the-shelf hold down ( something like http://smile.amazon.com/Rockler-Mini-Deluxe-Hold-Down-Clamp/dp/B006ZK3G1Y/ref=sr_1_4?ie=UTF8&qid=1429896862&sr=8-4&keywords=hold+down ) and dremel-ing off the “t-slot” connector so that I could just screw it into the spots in the wasteboard. It seems to me that as long as the size and threads are the same, it should work well.

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If you remove the T-slot end then you simply have a piece of all-thread which will spin freely — instead, flip it over and add a wing nut, or make some sort of handle for the T-slot end and turn it around.

Or, consider making your own — .dxf here: http://www.shapeoko.com/forum/viewtopic.php?f=11&t=1025&start=10#p9725 (and a useful photograph)

Another option when doing this sort of thing is an SHCS w/ a plastic handle: http://www.amazon.com/Shear-Loc-SLK-12R-Socket-L-Handle-Diameter/dp/B002IBD35S — these should be available in any hardware store.

What about something stupid like this. Just take 1 inch angle iron drill 2 holes tap the one and use furniture feet that have the bolt so they are adjustable. You could bolt the iron to the skateboard and just tighten the feet to hold the work price from the sides where ever you want

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That sort of thing works fine if you’re not cutting a piece through w/ a profile. There are flip jigs which make use of it.

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@paulkaplan comment gave me a good idea for some clamps that apply pressure from the side. I just made some test pieces on the x carve and have it running now with 1\4 bit and bumped the speed up to make sure it does not move. So far it’s looking good.

I will do a design for them in Easel and upload on to the site with photos over the weekend.

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I look forward to seeing more about this!

Does anyone know the final size of the 1000x1000 mm wasteboard? I need to get some mdf and I’m considering getting 1/4 MDF and layering it so that the bottom layer has T-track and the top layer can be cut into and replaced without the fear of hitting the Track.

If you have a 3D printer, this looks like a good option and was what I was going to start with:

@TravisLucia
If you plan to make your own Waste Board we have put together the following information for your review.

The engineering files for the 1000mm board (http://bit.ly/1F7kaxH) and silk screen file (http://bit.ly/1Ho03vw)

You’ll also need the hardware that comes in the kit but you can add them to your shopping cart separately.
a. 144 threaded inserts, 2 bags of part #30517-013
b. 14 pre assembly insertion nuts, 2 bags of part#25281-023
c. 14 Button Head Screws M5 x 20, 2 bags of part #25286-153

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@Zach_Kaplan thanks for the reply. I tried following the URL’s to look at the engineering files and was met with a screen saying the files were deleted or are missing/ “You don’t have permission to access these documents” I created an account and still had troubles.

Try this link:
https://workbench.grabcad.com/workbench/projects/gcl5zpCuwqCXWLvYktLQBc-2IHvossNo37ycTOkzg6gREW#/space/gcvs_XeRNVzNkfG_tFTAMd0C2lBbCsLcagOxXb1Jlki0kT/folder/858489

I think having a few options for material holding is key. Depending on the work piece and type of milling your doing one option might work better than another. I wasn’t a fan at first of using carpet tape but it has grown on me. The type i use holds the material slight above the waste board which saves a little wear on it if you cut down too deep. I do need to find that mega roll on Amazon since buying the smaller rolls can add up over time.

Would it damage the endmill if it cuts through the material and into the tape? I worry that the adhesive would gum it up and get stuck in the flutes.