What's your hold down method?

[HDTHEATER]

I have had my CNCRP for going on three years now and have had nothing, but good experiences with it. My spoil board has served me well and will need to be replaced soon. However, I want to see if I may want to look at alternatives for holding down material.

What I have today is a 1/2' MDF base with a 3/4" MDF spoil board. The spoil board has 4 holes in it and a grid carved into it to direct airflow from a shop-vac. Its not in the photo, but I have PVC pipe and valves to open and close each section when needed. This is he best shot I have from when I built it before dust collection was installed.



This method has been helpful when holding down thin sheet goods like 1/8" MDF, styrene, or foam. However, the bulk of the time I am cutting full sheets of 3/4" MDF and use multi-purpose screws to hold it in place. The shop-vac can't hold the MDF, not to mention it gets very noisy and running the Shop-Vac for hours on end is not good for it when there is little to no air flow.

Overall, I have been satisfied with what I have, but there have been times when a 49x97 sheet does not sit flat across the entire bed. Also, after a while you run out of places to put screws as the spoil board has too many holes in it. Not to mention, I am always scared I am going to hit a cross member.

What's your hold down method?

Thanks,

-Eric

Similar Threads:

• Help with RTM Method please?
• which method
• Newbie- Hold to hold tool holder while loosening nut
• Best method for Dry Run
• Best Method

[jo_ky]

I have a much smaller router, but the same question sort of applies, since the metal bed is not flat enough, and in sections (so not that rigid), so I use an MDF table. This is where I'm at:



It's made by Rockler. By my calculations, it would cost at least $225 in track to scale that up to 4' x 8'.

I'm still very new at this, though, so I'm also going to see what other responses you get, since I have the same question! For certain things I'm interested in doing, having vacuum as well would be great.

[jram]

Hi HDTHEATER,
Is this a Standard or Pro version? I am currently looking at either a 4x4 PRO or Standard 48x96 and am just trying to get some input from those who have had the machines for a bit.
Thanks!

[HDTHEATER]

I have a much smaller router, but the same question sort of applies, since the metal bed is not flat enough, and in sections (so not that rigid), so I use an MDF table. This is where I'm at:



It's made by Rockler. By my calculations, it would cost at least $225 in track to scale that up to 4' x 8'.

I'm still very new at this, though, so I'm also going to see what other responses you get, since I have the same question! For certain things I'm interested in doing, having vacuum as well would be great.

Your machines is too clean!

I think these setups work great when the material is smaller than the CNC bed. I used to have a CNC Shark and the entire bed was aluminum extrusion. I could clamp anywhere.

When I started, I thought vacuum was going to be my solution. However, Shop-Vac was my budget. It's way too noisy and inefficient. It works fine for a job that runs about 45 minutes.

I think a vacuum pump could be the way to go, but wouldn't know where to start to design such a thing nor what the expected cost would be.

-Eric

[HDTHEATER]

Hi HDTHEATER,
Is this a Standard or Pro version? I am currently looking at either a 4x4 PRO or Standard 48x96 and am just trying to get some input from those who have had the machines for a bit.
Thanks!

This is a Pro with NEMA 34 Electronics. I bought it all from CNCRP except the router.

[Gary-Wiant]

Not hold down related but mare about the router. Why isn't the table flat? I'd like to eventually get the same router but now I'm concerned with the build quality? Is it very rigid?

Thanks

[HDTHEATER]

Not hold down related but mare about the router. Why isn't the table flat? I'd like to eventually get the same router but now I'm concerned with the build quality? Is it very rigid?

Thanks

The CNC is top notch. I can’t say enough good things about it and the company.

It’s usually a sheet of material that wasn’t exactly flat. Plywood is the usual culprit.

Another factor is the spoil board. If I have a change in humidity, then I may need to re-surface the spoilboard as it may have changed on me.

Recently, my spoil board has been the real issue, which is why I know it’s time to rip it off and start over. The design I used had two layers of MDF glued together and they are starting to pull away from each other in the corners. What was once a 3/4” sheet is now just shy of 3/8” thick.

[Gary-Wiant]

Oh ok thanks, I'm glad to hear it's not the machine, I'm probably a long ways from upgrading my machine but I've been looking. I'm not sure between the regular and the pro model yet but I have some time for research.

Pursued machine tool camp 4x8 router came with 2 - 3/4" pieces of mdf for the table / spoil board if your concerned with humidity why not use some HDPE for your table? It should go anywhere. Then use a 3/4" piece of mdf for your spoil board. I know if you do any misting key isn't the answer but if you are just rout8ng woods & plastics you should be fine.

IM considering routing in some grooves for T-Slot rails, but I can't figure out how close together I should put them or if just along the X of Y or if I need a grid.

Good luck

[jo_ky]

Your machines is too clean!

Ha! I'm working on that.

[Gary-Wiant]

Approximately how much is shipping on a complete system? I assume they ship it freight truck

[Kosh]

I have my spoilbard machined in place with 20 mm holes for parf dogs and festool clamps. Then I cut t-slots for t-bolts that are either designed into my jigs, or go through wood hold downs.

[HDTHEATER]

Approximately how much is shipping on a complete system? I assume they ship it freight truck

It’s shipped in parts via ground shippers.

[HDTHEATER]

I have my spoilbard machined in place with 20 mm holes for parf dogs and festool clamps. Then I cut t-slots for t-bolts that are either designed into my jigs, or go through wood hold downs.

I like the setup. What do you use when your material covers the entire bed?

[jdog70]

I have a 2x4 cnc pro, have had it 2 years and love it, nothing but quality!

I use pocket hole screws directly through the material and into the MDF spoil board. Keeps the material very firm and flat. Usually need 6 screws for a 2X4 plywood piece
I determine the location of the holes for the screws by the pattern I am going to cut. I use v carve pro, and the first pass is peck drilling a temple for 'holes' for the pocket screws. This pass is only 1/16 deep. This way I know where the hold downs will bein relation to my pattern.

The pocket screws only stickup about 1/8" and are self taping (but I predrill with 1/8 drill to save the spoil board). The extra holes are not a problem and after you are used to the system it is fast.

[Kosh]

I like the setup. What do you use when your material covers the entire bed?

that's actually pretty rare for my applications (guitar parts mostly), but I have just used clamps around the edges.

I started out trying to build a generic MDF vacuum table (with fancy moveable gasket slots and removable boss plugs for putting the vacuum where I needed it, but it leaked too much (even though I tried to seal it) and the vacuum pump probably wasn't big enough. I just ended up using purpose built vacuum jigs. See my thread here:

http://www.cnczone.com/forums/musica...-software.html

or my youtube channel:

https://www.youtube.com/channel/UCH-...TYdNS4EkQGsVUQ

[dustbot]

Spoil board is routed with an array of slots that will receive 5/16" carriage bolts. T-nuts in the handle lock the hold down to the table. Easy to make and surprisingly strong.

[Blisswoodshop]

I have some thing similar to yours, but rather than shop vac, I have my dust collection holding the sheets down along with collecting dust next to router. I use a 3 HP dust collector and that seems to work for full sheets. Along with that, I have few t-slots along the table top. Currently looking to get some holes done to have some kind of cam clamps.

I have had my CNCRP for going on three years now and have had nothing, but good experiences with it. My spoil board has served me well and will need to be replaced soon. However, I want to see if I may want to look at alternatives for holding down material.

What I have today is a 1/2' MDF base with a 3/4" MDF spoil board. The spoil board has 4 holes in it and a grid carved into it to direct airflow from a shop-vac. Its not in the photo, but I have PVC pipe and valves to open and close each section when needed. This is he best shot I have from when I built it before dust collection was installed.



This method has been helpful when holding down thin sheet goods like 1/8" MDF, styrene, or foam. However, the bulk of the time I am cutting full sheets of 3/4" MDF and use multi-purpose screws to hold it in place. The shop-vac can't hold the MDF, not to mention it gets very noisy and running the Shop-Vac for hours on end is not good for it when there is little to no air flow.

Overall, I have been satisfied with what I have, but there have been times when a 49x97 sheet does not sit flat across the entire bed. Also, after a while you run out of places to put screws as the spoil board has too many holes in it. Not to mention, I am always scared I am going to hit a cross member.

What's your hold down method?

Thanks,

-Eric

[TwoWheelMikee]

I have a home brew setup that I have upgraded over the years with CRP hardware. I found that work holding from the top gets in the way a lot for the type of work I do and haven't used it in years. I switched to double sided tape, but the expense and strength of the adhesive made me search out another method. Now, I use the "blue tape and super glue" trick as my primary. It's been around for a while, but John from NYC CNC (youtube) has started using it quite bit recently. Additionally, I use two sheets of MDF stacked together as my spoil board. The first (lower) sheet I have used installed 1/4-20 threaded inserts every two inches around the parameter of the cutting area and a row down the middle. On the upper sheet I peck drilled a grid of 1/4" holes every two inches, that line up above the threaded inserts. This allows me to use 1/4" steel pins for alignment and 1/4-20 nylon screws/bolts through the pin holes to the threaded inserts. Blue tape and super glue hasn't failed yet, but if I want/need a warm fuzzy feeling, I will align the piece above the threaded inserts and I'll set the first operation to peck drill through the piece to allow the use of the nylon screws. This also allows for double sided milling on the machine, using the preexisting holes. I replace the top sheet as required and just re-drill the pin holes and I'm good to go.

[TwoWheelMikee]

Currently looking to get some holes done to have some kind of cam clamps.

I have used cam style clamps as well, and I found two issues with them. They work great for holding the work piece laterally, as in shifting on the table. But, I have found that they are not that good at holding the work piece down to the table. The tendency I saw was to lift the material away from the table and would be increased as you clamped harder. Also the side pressure on the piece may effect the structural integrity of the material as you cut through the material, especially if you a making through cuts close to the edge, like cutting a piece out. If you solve these problems, I would be curious to hear how you do it. The cam clamps did allow for quick change out of material for batching out items.

[Kosh]

I have used cam style clamps as well, and I found two issues with them. They work great for holding the work piece laterally, as in shifting on the table. But, I have found that they are not that good at holding the work piece down to the table. The tendency I saw was to lift the material away from the table and would be increased as you clamped harder. Also the side pressure on the piece may effect the structural integrity of the material as you cut through the material, especially if you a making through cuts close to the edge, like cutting a piece out. If you solve these problems, I would be curious to hear how you do it. The cam clamps did allow for quick change out of material for batching out items.

Legacy Woodworking has a set of clamps designed to solve that problem (they push in AND down):

https://lwmcnc.com/product/lowpro-t-track-clamps/

However, I have yet to get them to work correctly (and as well as their demo videos). This maybe due to how poorly their T-nuts fit into my custom t-slots. basically, when I try to tighten them they just move back in the t-slot. I'm withholding final judgment until I've had some better t-nuts made... but so far they are just collecting dust (and not from the CNC machine!).