CNC Workbench Top

[Martin Wasner]

If I received the .dxf, I'd redraw it to make sure it's right, as 20 years have taught me not to trust other people's CAD work.
And even if it only took 5 minutes (Which is all it would likely take), I'd charge $100 as well.

Pretty easy for an errant line to get a tool attached to it that is 5" into the bed....

I agree it's best just to use it as a reference and start over

[Gerry Grzadzinski]

I bored them with this bit https://www.vortextool.com/320057.html for my table. If using a machine of Martin's class, I would not be bothered with a pocket tool path, but I would be less inclined to accept that from someone with an entry level machine for fear of oblong holes. The festool dogs are around 19.5mm - 19.8mm if I recall correctly when I was measuring them. Sloppy holes to save $30 would annoy me.

And if the machine has a boring head, they probably already have one, as 20mm is a common size for some Euro hardware. On our Morbidelli, a boring bit will always give you a much better hole.

[Jerome Stanek]

Pretty easy for an errant line to get a tool attached to it that is 5" into the bed....

I agree it's best just to use it as a reference and start over

How would it go down that far don't you input max depth

[Martin Wasner]

How would it go down that far don't you input max depth

Yes, but that doesn't mean something gets missed, or overlooked. I haven't plowed into the table yet, I hope never to do it

[Mark Bolton]

Back in the edit on phone and post deletes....

If the shop he was referred to is doing CNC work that a millwork shop is happy enough to feel confident referring him to I would think surely to god the guy (guys machine) can bore a round hole with a profile toolpath. If he cant there are far bigger problems with a sheet full of fairly precisely placed holes whether they are profiled or drilled. Again it comes back to cost. If the customer wants to buy tooling, and pay me to free up a collet holder and collet, set the new tool, measure the new tool, and then remove the tool and return it to the customer (all adds up to another hour?).

We bore precise holes (measured with a snap gauge and a set of mic's) all the time. If someone is boring oblong holes, they are not going to get the hole spacing across a sheet right, and they are not going to be getting work and referrals.

[Mark Bolton]

Yes, but that doesn't mean something gets missed, or overlooked. I haven't plowed into the table yet, I hope never to do it

Agreed. There is no need for the DXF anyay. The job will likely be drawn by anyone who runs it so they are comfortable with it. All it is is a sheet with an array of holes of a given size. Two minutes to draw, toss a scrap on the table, profile a hole, measure it, adjust your toolpath or tool size, run another test, and run the job. I have my tools measured accurately enough that I would pretty much feel comfortable running the job straight away. Im anal and check my dado widths and actual cut dimensions pretty regularly with gauge blocks or gauges and mic's and adjust my actual tool sizes accordingly. I'd be highy surprised if I didnt get a dead round hole in an inch lol. We just ran some 20" rounds for another shop that had to be pretty spot on and the guy couldnt believe they were dead on.

[Bruce Page]

Yep, it’s easy to screw up. I drew this game piece up in AutoCAD and imported the dxf into Aspire for toolpathing. Made 24 of them. As Murphy would have it, it wasn’t until after I was done that I noticed that I missed one of the marble hole vectors.
I had to set up and add the feature one at a time. Grrr...

[Mark Bolton]

Yep, it’s easy to screw up. I drew this game piece up in AutoCAD and imported the dxf into Aspire for toolpathing. Made 24 of them. As Murphy would have it, it wasn’t until after I was done that I noticed that I missed one of the marble hole vectors.
I had to set up and add the feature one at a time. Grrr...

We all have a litany of situations like this. I dont run full cab jobs daily like Martin, but when I do its inevitable that one of the 3.278 million variables in my cab software didnt get adjusted globally, or did get adjusted globally and should have been applied only to tall linens, or some other infinite number of potential clusters. We run parts for other shops each of which has their own set of goofy construction styles.

It can be a nightmare for sure. Especially when the process is suppose to have the advantage of feeding some material and going and doing something else while its running but this little gremlin on your shoulder is poking you in the neck telling you you surely forgot something so you stand there and watch the entire time...

[Martin Wasner]

Think there's any market for these? People replacing their tops? I'd make a dozen 31x48 pieces and throw them on the shelf and just keep an ad going on Craigslist for $40

I'd buy a bit to do that. Load it in the drill block and just leave it. Wouldn't take five minutes to run a full sheet I'm betting.

Or it's not worth it.

[Martin Wasner]

Back in the edit on phone and post deletes.....

Switch to the desktop version, then edit. The mobile version of the site won't let you edit.

[Mike Goetzke]

Think there's any market for these? People replacing their tops? I'd make a dozen 31x48 pieces and throw them on the shelf and just keep an ad going on Craigslist for $40

I'd buy a bit to do that. Load it in the drill block and just leave it. Wouldn't take five minutes to run a full sheet I'm betting.

Or it's not worth it.

$40 each - where are you located?

[Mike Goetzke]

Update on my project. I chose a local sign shop that is very close to me - they have a CNC router. Guy had me bring a scrap board to rout out some different diameter holes to test fit my bench dogs. Glad we did this the hole size that the Festool MFT/3 has was way too sloppy for me. We had to take it down a few thousands. BTW - couldn't believe 0.001" diameter increments we so noticeable.

So the hole size had to change and for some reason the DXF file I gave them had the holes oval by 0.001" and my slot features didn't come out right. Yes, they used my centerlines but had to redraw it. In the end it cost me $200 including material for three tops that should last forever.

I use a 2-D CAD program called DeltaCAD and it's worked well for non-complex things I draw up once in a while. I'm two versions behind the latest and they claim the DXF has been improved. Is it worth it to upgrade for $30 or 1) would CNC guy still need to redraw or 2) is there other software I should purchase?

Thanks


BF173207-C458-4ECF-878C-5D3F60640B64.jpg

[Jim Becker]

Interesting design. You've given me a few things to think about as I mentally design my own future replacement bench top.

I would have re-drawn that in my Vectric software rather than use the DXF file...with a regular pattern like that and using array copy or array toolpaths, it would be a snap.

[Mike Goetzke]

Interesting design. You've given me a few things to think about as I mentally design my own future replacement bench top.

I would have re-drawn that in my Vectric software rather than use the DXF file...with a regular pattern like that and using array copy or array toolpaths, it would be a snap.

I studied many other slab design ideas. The slots fit my Irwin Quick-Grip and Bessy parallel jay clamps. The offset set of holes are so the saw blade kerf line doesn't cut through a set of holes. The smaller slots are to act as lifting handles.

What would I do different? 1) after reading your post maybe should have punched few 3/4" holes in it. 2) slots are nice for clamps but no good space to lay screws/pencils/small tools.

Mike

[Mark Bolton]

While no one can say for certain I can only say for myself that would never stand behind a customer drawn file with regards to your satisfaction. I may be willing to take your file and just toolpath it as you request and what comes out of the geometry is on you but if you were asking me for those tops, with a certain fit tolerance on the holes, spacing, and so on, I would either ask you to specify that tolerance and then draw the job myself, run a couple small test hole to check bore and spacing, and then run the job. Either that or I'd ask you for some parts to check the fit with the actual part.

It not like your generating code for the machine (which anyone would be insane to run without checking if they even allowed it at all). But machine shops do this every day. They are supplied a drawing with holes and features each of which have specifically called out tolerances. Then never have any physically mating parts in hand so they simply make sure they are within tolerance.

I would argue that in wood the .001" change that you found apparent may likely have been tool deflection (spring pass), backlash in the machine, and so on. But for sure, changing things by just a few thousandths really is apparent especially when you get into mating parts and machined parts mating with other machined parts. The problem we most often find was touched on here and that wood moves a LOT. So you machine a part for a close tolerance trying to be deadly accurate and three days later the cut face that you exposed to the atmosphere absorbs moisture and poof. Your parts no longer fit. This happens with super close fit ply and melamine parts all the time. You try to run them super tight but you'd better be putting them together immediately because 4 hours sitting on the racks and they may require some persuasion.