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Thread: CNC Ordered...(now ready to ship!)

  1. #16
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    David, I'm sure this will be an interesting journey. I "get" the software side and learn that kind of thing quickly, but as you clearly state and many others have said, the application, thereof, doesn't always result in what is expected action...including, um...tool longevity. LOL

    Brad, I actually do have a Gast vacuum pump that I plan on using with the CNC at some point. I originally bought it for vacuum chuck work at the lathe and later also used it for vacuum bag veneer work on a few projects. So I appreciate the reference you provided for the gasket material. I'm sure that the tooling thing will be a real trip...it's like a menu at one of the old-fashioned diners that is about 20 pages long...so many choices.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  2. #17
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    Unless it is a pretty good size Gast pump it may only work for pods where you do not cut thru. I bought a 25"Hg, 1cfm Gast pump for pods, but that was too small (want one?haha). Without a perfect seal that pump was slow to grab my parts and generate the vacuum needed for cutting. That was replaced with a small Becker pump that does up to 25inHg, 4.5 cfm (similar to my one for vacuum bags) and it works for pods, but that is it. For a table top you need more CFM for thru cuts. Gary's original vacuum started the single phase option for our machine sizes, and it works remarkably well for entry level machines. I get up to 9in HG and I recall Gary measure the CFM to be in the realm of 300 - 400 cfm. I can hold parts as small as 4"x24" with as little as 5in HG so long as the last pass is an onion skin. Smaller than that, and I need something else. Small parts are annoying.

    I almost bought a fairly good size starter set of cutters from the company I seem to deal with most of the time when I started, and I am sure glad I did not. I had no idea what I really needed at that time.

    With your 4x4 table your options are great. I think you will find your other machines will become lonely. 90% of the time my saw is only used now to knock down large pieces and if I had a supplier like Mark with a two sided planer, I think the jointer/planer would become lonely too. You quickly will become pretty accustomed to parts coming off the table 100% complete, near perfect, and ready for glueup. I built a steel cart last weekend, and the number of silly mistakes made showed me how reliant I am becoming on software and models.

  3. #18
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    Dec 2007
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    Congratulations on your purchase Jim, hope it turns out to be as much fun and $$$ as expected (or at least one of those!)

    A question re vacuum pumps - are the cfm ratings mentioned above at 0", 10", or 20" Hg? I noticed Grainger rates them at those levels, and the ratings plummet as vacuum increases.

    I too have a 3/4hp Gast pump that I've used for vacuum chucks. I try to use it with a receiver tank, just in case the pump ever shuts off for whatever reason, to give a few extra seconds of vac before things start flying.

  4. #19
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    A vac system can be handy for some but its useless to me based on the kind of work I do. I do have a couple vac pucks that I can use for very small jobs that are the most difficult to fasten to the table for engraving and a larger one that I made from a small piece of Corian. The cost of a vac system can often be more than a CNC Router. I did build an auxilliary hold down table from a piece of Corian that is about 18" by 30" and I installed four of the large aluminum tracks on the surface. This one is really handy for odd shaped signs or when I want to install one or multiple jigs for special projects.

    I'm still using the original spoil board that I installed when I first got my router. It will need to be replaced soon and I'm considering using PVC sheet instead of MDF this time. I really dislike MDF and the nasty dust.

  5. #20
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    Brad, I'll have to check the specification on the Gast pump I have...it's buried in my Stubby lathe's base currently. I bought it years ago from a surplus company for "a very good price". Even if it isn't appropriate for holding larger work, I'm sure it will come in handy for some things...many of the "ideas" I have center around smaller things which I have no doubt it would suck down and hold tightly with a properly constructed panel.

    Keith, I'm also not fond of MDF, so while anything I do initially for a spoil board will likely be made out of it since it will "absorb human errors cost effectively" in the beginning. But after that, I'll not be squeamish about exploring cleaner alternatives that are reasonable for what is essentially a disposable element.
    Last edited by Jim Becker; 01-25-2018 at 5:05 PM.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #21
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    Richard, all professional model vacuum pumps have curves that show the CFM rating at various vacuum levels. Here is a sample curve: https://www.becker-international.com...?id=0000066230 The vacuum drops quickly as you get open flow (cut thru). The wider the bit, the more air flows through. Basically, the motor cannot keep up to the air demand. That is why the industrial ones get so big. Grainger will have curves as well. I can watch the vacuum drop on the vacuum for my table top as I cut thru. When the top is sealed by parts, my home built vacuum will read about 9" HG, and by the time I have cut through for all the parts it will drop to as low as 5" or so. If I do not cover up all the voids on my table it is always lower as well because the air flows thru the bleeder board. With pods, I never cut thru or only cut thru outside the pod. Then the readings always max out because the air flow is zero. I am cutting some dovetail drawers now and I need full vacuum because the surface area of the pods is very small. Hold down is a simple function of area. 25inHg results in roughly 12.5psi hold down. There is a google converter that is close enough for our use. My pods are 3"x4", so I have approximately 150lb of hold down per pod. You also have to watch the sliding force. If you use big thick gasket material your parts may move when the cutter pushes at the part. Too thin is not good either unless you stock is absolutely perfect. I had some parts not long ago where the stock had a slight bow. It was tricky to get them to seal.

    Keith, I quite like the phenolic top I put on. Trespa makes a nice 20mm (up to 60"x120") phenolic product that is a bit cheaper than the others I looked at. It is awful to cut, but it taps well.

  7. #22
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    Quote Originally Posted by David Falkner View Post
    I took the same route while I waited on delivery, Jim, working with the software I planned to use. I use Fusion 360 and by the time our machine arrived and I finished building it I thought I was ready. It took all of 5 seconds to snap the first bit - LOL! But the time I invested in learning what I could on F360 was invaluable. Once I got up and running a whole lot more of F360 began making much more sense to me, especially the CAM part.

    David
    Fusion's great if you have 3d parts! Certainly has its quirks but saves a lot of time on the CAM for mechanical parts vs a 2.5 package like Aspire.

    Getting GWizard Calculator is what I tell every new CNC owner to do - it gives you a pretty great ballpark figure for feed rate and spindle speed so you either snap an endmill or rub the endmill till it sets something on fire haha. It's really pretty cheap too! https://www.cnccookbook.com/g-wizard...lator-pricing/

  8. #23
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    Quote Originally Posted by Brad Shipton View Post
    Keith, I quite like the phenolic top I put on. Trespa makes a nice 20mm (up to 60"x120") phenolic product that is a bit cheaper than the others I looked at. It is awful to cut, but it taps well.
    Brad, is the Trespa phenolic a hard material, something like science table tops?

  9. #24
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    Yes, it is a lab top material. It comes in one version that has good chemical resistance and another that is resistant to far more chemicals. http://www.trespa.com/en-gb/toplab The main reason I used this is it was about the only reasonable solid surface material I could find in 5'x10' near me. I cut it into two for handling and used the thick epoxy to glue the joint. Mick has a really good video of replacing his table top if you have not seen it.

  10. #25
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    Brad, following up on the Gast pump I have, it is indeed a smaller unit at 1/3hp, so while it will be perfectly capable of small fixture holding, no way would it be appropriate for something larger. I'm sure I'll have fun experimenting with it!

    Check is sent, so as far as I'm concerned, my shop is now officially "pregnant" and waiting for the birth of it's new baby.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #26
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    Thanks Brad.

    Jim, if your clock is going as fast as mine it will seem like only a few days. The years seem to be flying by as fast as months did in the past however February will creep painfully along...it always does

  12. #27
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    Quote Originally Posted by Keith Outten View Post
    Thanks Brad.

    Jim, if your clock is going as fast as mine it will seem like only a few days. The years seem to be flying by as fast as months did in the past however February will creep painfully along...it always does
    This will slow down time for him. In fact it may seem like time is going backwards.

  13. #28
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    black river falls wisconsin
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    Ya jim, Every time you go in the shop will look at the spot it's going....

  14. #29
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    48 hour days..
    Mine took ~ 7 weeks to delivery. Seemed like 14.
    Please help support the Creek.


    "It's paradoxical that the idea of living a long life appeals to everyone, but the idea of getting old doesn't appeal to anyone."
    Andy Rooney



  15. #30
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    Fortunately, I have stuff to do in the meantime...finish the current double tack trunk commission, do another small commission for a dozen custom sized photo panels for a photographer friend, build some floating shelves to match the recent "kitchen continent" commission, build new upper cabinets for our kitchen, get the remaining donations cataloged and out the door from the upstairs of my shop, insulate the ceiling, install the electrical for the CNC and control computer, finish setting up the business legally with my accountant, etc., etc. Oh, and daily taxi service for my older daughter to get to work. And the time will still crawl. LOL
    --

    The most expensive tool is the one you buy "cheaply" and often...

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