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I've had a CNC router for over 20 years now.? I have a ShopBot PRT.? At some point I plan on upgrading, but I've got to finish moving into my new shop first.? Here are my observations:

• CNC allows me to do things that I am incapable of doing by hand.
• CNC requires good software.? Some of the best packages are thousands of dollars.? You also have to know how to use it, which takes time and dedication.? I'm a computer geek by trade so I don't find it at all imposing, but there are plenty of things that I still can't do well or quickly with the software because I don't spend enough time practicing.? I'm sure it would be different if I was doing projects every day.? Bottom line -- don't underestimate the time commitment associated with learning to use the software well.
  
• CNC is great for things that need to be precise or that you want to make a lot of.?
  
• CNC is awful for doing ad hoc work.? You have to do lots of design and setup up front.? You can't just "knock something out"
• CNC can be painfully slow.? Part of this is my particular machine.? I'm sure a modern machine with a high horse power spindle would do better, but saw blades cut straight lines a lot faster than router bits do and give a nicer finished edge, even if you have the ultimate machine (and the power source to feed it).
  
• Don't underestimate how much effort goes into holding down your materials.? Vacuum systems can help, but they add to the costs, complexity, and power consumption.
• The nice thing about CNC jobs is you can set them up and let them run.? This is also the horrible thing.? CNC machines, even with spindles instead of routers, are loud, and you really can't leave them unattended.? Bad things, very bad things can happen if you set something wrong, or a collet wasn't quite tight enough, or there was an embedded nail you didn't know about.? You can have a fire or a ruined tool in a heartbeat.? So you're stuck there watching a loud screaming machine do it's thing.? The first couple of times it's magical.? After that it's boring.?? You'll want other tools in your shop to work with while you wait for the CNC.? And hearing protection.? Very good hearing protection.
  

CNC is a powerful creative tool and I'm very glad I have one.? I don't regret the cost or the space.? That said, while I've done shelving units and cabinets using it, given the limitations of my machine, it's not my first choice.? It's faster for me to knock things out on a saw and use the CNC for fancy decorative stuff.? For some of the small stuff I use my laser cutter instead, as I don't have to fuss with work holding.? When I first got the machine I thought I would use it for everything.? Now I use it for things that require precision, that require embellishment, or for things that I want to create multiple copies of.? When I upgrade machines I expect I'll revisit the work holding part of things and focus on improvements I can make there to make the CNC machine more effective.? I also plan on upgrading to a spindle (quieter) and a tool changer so that I can hog things out with a big bit and then switch to smaller bits for detail work and not have to fuss with it.

--Michael Garrison Stuber

Hi,

I am trying to find a replacement for my sliding table saw that takes less space but still allows to build hardwood furnitures, builtins, closet systems, kitchen cabinets.. I am not interested in a standard table saw and I plan to keep my jointer/planer, miter saw for some of the hardwood task. I know that CNC routers with flat bed are really good for cabinet box/sheet good, but it seems that the new machines with some pod tables are able to manage hardwood too. I am not a production shop, just looking to see if I can reduce the footprint (2 times the sliding table length, the rip capacity and the outrigger).

If anyone has insight on using a CNC for sheet good and hardwood and would like to share, I will appreciate. In term of machines, I am looking at middle to high end version from Shopsabre, CAmaster, Freedom Patriot as they all offer compact design for a 4x8 table.

I know that there is a learning curve from software and cutting technics (flow, order, tooling, holding parts), but as hobbyist I do not see any issue with that.

Thanks for all feedback,

Bill

-- 
Michael Garrison Stuber

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I think this is a case of "One of these things is not like the other" ? on a level that makes them not swappable.

How deep? you going to cut with a CNC router?

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Remember, you're depth of cut is limited by the length of your tooling.? In general, the longer the tool is, the larger the diameter is going to be.? Cutting 8/4 stock is going to require at least four passes (probably more, but it depends on the machine) with a 1/2" diameter cutter.? That's a lot of waste.? You might be able to get away with using a 3/8" diameter cutter, but you're probably not going to find a 1/4" diameter that is long enough to provide the required clearance.

In terms of rip versus crosscut, the CNC machine doesn't really care.? It's more of a question of conventional versus climb cutting, as everything is being done with a spinning router bit rather than a blade.? Also keep in mind that you're not going to get square inside corners.? There are ways to mitigate this some (depending what you're trying to achieve) such as dog bones, or changing tools to small a smaller diameter cutter, etc. but it's a fundamental limitation of the type of cutting you're doing.

Regarding bed size, you can get machines with longer beds if desired.? I'm seriously considering 5x10 for my next machine.? This would let me work with two pieces of 5x5 baltic birch at once if desired, or leave a rotary axis at one end while still having room for a 4x8 sheet of plywood.?? But yes, the bed size is the basic limitation, unless you're willing to have stock overhang one end and reposition it after a series of cuts.

You'll need to work out how you're doing your registration for joinery.? On a saw there's a fence.? When well-tuned you know exactly the relationship between the fence and the blade.? There is no "fence" on a typical CNC machine.? You would either need to do all of your cutting and joinery in one operation so that the joinery aligns exactly with the other cuts being made, or you need to provide a mechanism for registration.? On my CNC machine I implemented something like a festool MFT with 20 mm holes in a grid pattern across the bed.? I then milled a set of solid hardwood fences that I can pop in anywhere in the grid pattern on the table.? I can them use festool FMT clamps or some of the lee valley bench pups to hold stock against the fence.? I have program that aligns the cutter head with the edge of my fence (as opposed to the proximity switches).? This works pretty well for allowing me to do repeatable cuts into the surface of my stock, but it would be a fail for doing any profile cuts around the stock.? By using hardwood for my moveable fences there's not too much harm done if screw up and run the tool into the fence.? (Side note here, I've ended up with a variety of brass, plastic, wood, and aluminum for hold-downs so I don't do too much damage if I've misjudged a clearance.? I'm embarrassed that I make these occasional mistakes with the machine, but they continue to happen, so I have just made a point to make them less painful.)

Again, I'm not saying it can't be done, but you're definitely going to need to think through the order of operations in your joinery and how you're going to solve the combination of hold down and registration issues.

Thanks for all the feedback,

I do get than for most of you this is not a replacement, but for my use case I am still no convinced. For examples, I do not cut anything taller than 8/4. I have done cross cut on 4x4 or 4x6, but this can be done on a miter saw. I do not have a shaper, and do everything on my table saw and jointer/planer. I plan to keep my jointer/planer and miter saw.

I do get that thin rip (1/8") or face frame stock are too thin for a CNC. As I do those kind of rip cuts, I can live with a small traditional table saw along a wall for that. Then I am left with bigger hardwood stocks out of the jointer/planer for glue ups or others that I normally cut to final size on my table saw. First, I guess I can get final size on the planer.
However, can you rip and cross cut 8/4, 4/4 hardwood with a cutter on a CNC as well as do joinery like dado, rabbet on those same 8/4, 4/4? Let's assume lumbers have been jointed and planed and are big enough to work either with a modest vacuum such as hurricane type or a small rotary vane vacuum pump for pods table? Like 4 inches wide at least and a couple of feet long, I guess?

What about aggregates? Brian mentioned them and I am wondering what are those aggregates used for beside joinery on the side (drilling) and bevel cut? Are they adding anything for hardwood cutting?

I have not yet a shaper, but I am wondering which kind of shaper tasks a modern CNC with vacuum as mentioned above can do without crazy jigs? I see stock longer than 8 ft not feasible on a CNC, but I do not know enough about CNC and shaper to know anything here.

Thanks

Bill

-- 
Michael Garrison Stuber

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Fascinating video Brian.? I really liked the plunge cut chain-saw head for mortises.? If I wanted to make a couple hundred thousands of something and I had the necessary capital, this would be a lot of fun.

For an idea of what’s out there in aggregate heads, watch this video:??

The problem here is the machines stout enough to handle them are usually pricey, like over $100k. They are either Cat40 spindles or HSK63, so big in hp too. And don’t forget, each aggregate head could easily run $4000 to $10,00 in cost. Ones where you see the head rotate, to saw say in the X and Y directions, you have to have a C axis built into the spindle.

None of these things are usually found in a 4x8 machine sized for the home shop. Now, can you edge joint large slabs with an end mill, sure, not a problem, and do tenons and mortises, most likely if you have enough Z travel. Ripping boards, not so much if they get very thick. I don’t like to cut with smaller than a 1/4” bit to go through 3/4”, for 8/4 I would be looking at 1/2”, maybe 3/8” if you run slow and multiple depths. That’s a lot of wasted material and time to just cut something.

Facing slabs or glue ups is easy, not as fast as a planer or drum sander, and you still have to figure out how to hold it.

Brian Lamb
blamb11@...

On May 23, 2021, at 9:30 AM, Bill James via <xxrb2010@...> wrote:

Thanks for all the feedback,

I do get than for most of you this is not a replacement, but for my use case I am still no convinced. For examples, I do not cut anything taller than 8/4. I have done cross cut on 4x4 or 4x6, but this can be done on a miter saw. I do not have a shaper, and do everything on my table saw and jointer/planer. I plan to keep my jointer/planer and miter saw.

I do get that thin rip (1/8") or face frame stock are too thin for a CNC. As I do those kind of rip cuts, I can live with a small traditional table saw along a wall for that. Then I am left with bigger hardwood stocks out of the jointer/planer for glue ups or others that I normally cut to final size on my table saw. First, I guess I can get final size on the planer.
However, can you rip and cross cut 8/4, 4/4 hardwood with a cutter on a CNC as well as do joinery like dado, rabbet on those same 8/4, 4/4? Let's assume lumbers have been jointed and planed and are big enough to work either with a modest vacuum such as hurricane type or a small rotary vane vacuum pump for pods table? Like 4 inches wide at least and a couple of feet long, I guess?

What about aggregates? Brian mentioned them and I am wondering what are those aggregates used for beside joinery on the side (drilling) and bevel cut? Are they adding anything for hardwood cutting?

I have not yet a shaper, but I am wondering which kind of shaper tasks a modern CNC with vacuum as mentioned above can do without crazy jigs? I see stock longer than 8 ft not feasible on a CNC, but I do not know enough about CNC and shaper to know anything here.

Thanks

Bill

-- 
Michael Garrison Stuber

开云体育

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Brian,

??? I really appreciate the tip to the Hurricane unit.? I didn't know it existed.? Have you ever measured how many amps the system draws in practice?

1. CNC is indeed repeatable, results vary somewhat with size of end mills, depth of cut and feed rates. Good methods and practices are still required though.

2. Software is ?great, just depends upon what you want to pay. Mozaik is probably the best out there, but it will cost you $125-$150 a month subscription fee to do what you want. I found another option as I don’t need the fancy visualization/rendering software for customer presentations. Cabinet Parts Pro, I think it’s called, free to try (will do up to so many sheets of material at once) or $250 for the full version. As for how long it takes, not very much… I did a two drawer box, blind dado construction and even made the drawer boxes as a first test and had it done in an hour on the computer, then took way less than 30 minutes to cut it out…. and that was the very first time using the software.

3. You don’t need 50hp vacuum pumps. I went with a Black Box Hurricane, runs on 220V single phase less than 30 amps. It pulls 11” of vacuum and is more than adequate for a 4x8 machine cutting sheet goods. If you want to cut solid wood, buy pods and get a decent sized vacuum pump like a Welch, or even an air powered vacuum generator, although those suck a lot of CFM of air.

Brian Lamb
blamb11@...

On May 24, 2021, at 7:33 AM, Joe Jensen <joe.jensen@...> wrote:

I’ve lusted after a CNC for 20 years for my hobby shop. I am an engineer who has worked in high tech for 36 years so the CNC stuff is definitely of interest.? As I’ve dug in a few things I’ve concluded;

1. CNC ideal for precision
2. CNC of sheet goods is awesome with the right software
3. Holding down material is critical.? Big sheet good CNCs use huge vacuum pumps, like 50HP.? Hardwood, I expect would be fiddly. If you got a high end CNC with movable vacuum pods maybe.
4. With CNC you go from human dexterity skills to CAD skills

?

In the end I keep thinking for the kind of things I build, furniture and cabinets, it would take a lot longer to do with a CNC with a high percentage of that time spent on the computer.? That said, unless I am building a cabinet to fit in specific place I don’t really do plans or cut lists.

?

From:?[email protected]?<[email protected]>?On Behalf Of?Bill James via?
Sent:?Saturday, May 22, 2021 2:00 PM
To:?[email protected]
Subject:?[FOG] replacing a sliding table saw with a CNC router

?

Hi,

I am trying to find a replacement for my sliding table saw that takes less space but still allows to build hardwood furnitures, builtins, closet systems, kitchen cabinets.. I am not interested in a standard table saw and I plan to keep my jointer/planer, miter saw for some of the hardwood task. I know that CNC routers with flat bed are really good for cabinet box/sheet good, but it seems that the new machines with some pod tables are able to manage hardwood too. I am not a production shop, just looking to see if I can reduce the footprint (2 times the sliding table length, the rip capacity and the outrigger).

If anyone has insight on using a CNC for sheet good and hardwood and would like to share, I will appreciate. In term of machines, I am looking at middle to high end version from Shopsabre, CAmaster, Freedom Patriot as they all offer compact design for a 4x8 table.

I know that there is a learning curve from software and cutting technics (flow, order, tooling, holding parts), but as hobbyist I do not see any issue with that.

Thanks for all feedback,

Bill?

-- 
Michael Garrison Stuber

开云体育

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I don't have the neighbor problem (other than my lovely wife and the mountain fauna) but being off-grid, power draw is a constant concern.? I tap out at about 12kw total simultaneous consumption which has to cover the CNC, the spindle, and the dust collection, so I've basically stuck with mechanical holddowns, but if I could get away with 2500 watts for doing sheet goods, I might actually have enough power to do it.

I just got it hooked up the other day, and my son stole my clamp on amp meter yesterday… so I’ll have to wit until I get it back from him. The paperwork I have from Black Box says the motors are 7.5amps, and there are four inside the Hurricane, so it’s supposed to draw 30amps. That would be all pipes wide open, which you won’t run that way, you’ll zone down and probably be sucking thru the spoil board and have parts stuck on top, so you will most likely be drawing 20-25 amps most of the time in use, that’s with 4 motors running and from what I hear, if I’m cutting full 4x8 sheets, I can run two motors and get enough hold down. Then you’d be drawing 10-12 amps type of thing.

One bad thing… it’s noisy… I won’t be running it without the shop doors all shut or the neighbors will get real tired of it, real fast. The vane style pumps are quite a bit less noise… but again, this is what I found (used) and could afford, both monetarily and electrical draw.

Brian Lamb
blamb11@...

On May 24, 2021, at 2:00 PM, Michael Garrison Stuber <mtgstuber@...> wrote:

Brian,

??? I really appreciate the tip to the Hurricane unit.? I didn't know it existed.? Have you ever measured how many amps the system draws in practice?

On 5/24/2021 9:29 AM, Brian Lamb wrote:

1. CNC is indeed repeatable, results vary somewhat with size of end mills, depth of cut and feed rates. Good methods and practices are still required though.

2. Software is ?great, just depends upon what you want to pay. Mozaik is probably the best out there, but it will cost you $125-$150 a month subscription fee to do what you want. I found another option as I don’t need the fancy visualization/rendering software for customer presentations. Cabinet Parts Pro, I think it’s called, free to try (will do up to so many sheets of material at once) or $250 for the full version. As for how long it takes, not very much… I did a two drawer box, blind dado construction and even made the drawer boxes as a first test and had it done in an hour on the computer, then took way less than 30 minutes to cut it out…. and that was the very first time using the software.

3. You don’t need 50hp vacuum pumps. I went with a Black Box Hurricane, runs on 220V single phase less than 30 amps. It pulls 11” of vacuum and is more than adequate for a 4x8 machine cutting sheet goods. If you want to cut solid wood, buy pods and get a decent sized vacuum pump like a Welch, or even an air powered vacuum generator, although those suck a lot of CFM of air.

Brian Lamb
blamb11@...

On May 24, 2021, at 7:33 AM, Joe Jensen <joe.jensen@...> wrote:

I’ve lusted after a CNC for 20 years for my hobby shop. I am an engineer who has worked in high tech for 36 years so the CNC stuff is definitely of interest.? As I’ve dug in a few things I’ve concluded;

1. CNC ideal for precision
2. CNC of sheet goods is awesome with the right software
3. Holding down material is critical.? Big sheet good CNCs use huge vacuum pumps, like 50HP.? Hardwood, I expect would be fiddly. If you got a high end CNC with movable vacuum pods maybe.
4. With CNC you go from human dexterity skills to CAD skills

?

In the end I keep thinking for the kind of things I build, furniture and cabinets, it would take a lot longer to do with a CNC with a high percentage of that time spent on the computer.? That said, unless I am building a cabinet to fit in specific place I don’t really do plans or cut lists.

?

From:?[email protected]?<[email protected]>?On Behalf Of?Bill James via?
Sent:?Saturday, May 22, 2021 2:00 PM
To:?[email protected]
Subject:?[FOG] replacing a sliding table saw with a CNC router

?

Hi,

I am trying to find a replacement for my sliding table saw that takes less space but still allows to build hardwood furnitures, builtins, closet systems, kitchen cabinets.. I am not interested in a standard table saw and I plan to keep my jointer/planer, miter saw for some of the hardwood task. I know that CNC routers with flat bed are really good for cabinet box/sheet good, but it seems that the new machines with some pod tables are able to manage hardwood too. I am not a production shop, just looking to see if I can reduce the footprint (2 times the sliding table length, the rip capacity and the outrigger).

If anyone has insight on using a CNC for sheet good and hardwood and would like to share, I will appreciate. In term of machines, I am looking at middle to high end version from Shopsabre, CAmaster, Freedom Patriot as they all offer compact design for a 4x8 table.

I know that there is a learning curve from software and cutting technics (flow, order, tooling, holding parts), but as hobbyist I do not see any issue with that.

Thanks for all feedback,

Bill?

-- 
Michael Garrison Stuber

-- 
Michael Garrison Stuber

开云体育

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Thanks Brian.? The Black Box page is pretty thin.? Did you already have a plenum in your machine, or did you do everything from scratch?? Was there any particular plan you followed?? I'd be curious what that aspect of implementing things looked like.

Well, off grid presents it’s own set of challenges. Once I get my meter back… who knows how long that will take…. I’ll see if I can get a reading for you. By then I should have some cutting under my belt and have a better idea of how it holds with two vs. four motors. I know that with my manifold valves all closed, I’m getting as much vacuum, 11” or so, with two vs. four, so that number is my max vacuum I’ll ever see with these motors. It just remains to be seen how much leakage you get with how big of an area covered on the table. I did four 2’x4’ zones ?and plumbed it such that I can concentrate all the CFM on any combination of zones from 1 to all four.

Brian Lamb
blamb11@...

On May 24, 2021, at 2:52 PM, Michael Garrison Stuber <mtgstuber@...> wrote:

I don't have the neighbor problem (other than my lovely wife and the mountain fauna) but being off-grid, power draw is a constant concern.? I tap out at about 12kw total simultaneous consumption which has to cover the CNC, the spindle, and the dust collection, so I've basically stuck with mechanical holddowns, but if I could get away with 2500 watts for doing sheet goods, I might actually have enough power to do it.

-- 
Michael Garrison Stuber

开云体育