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TimS
07-06-2011, 09:47 AM
I've been poking at woodworking for many years, mostly traditional hand tools but some modern stuff as well. Having recently retired from high-tech, I have more time for my hobbies.

Early this year, I gained access to a ShopBot (48x48 table with standard controller). I took their orientation class but before I'd actually tried making anything on it, I also gained access to a 60x96 PRSAlpha ShopBot at another place. The first was at Sawdust Shop in Sunnyvale, CA while the PRSAlpha access is through TechShop.

My first planned projects were going to be small, simple things until a buddy asked if ShopBot could be used to create a project I'd recently told him I saw on TV. That project was part of Woodsmith Shop's episode 404…a set of four small stacking sawhorses made from a single sheet of 3/4" plywood. You can see their version at:

http://www.woodsmithshop.com/download/404/stackingsawhorses.pdf

I redrew it from scratch in VCarve Pro as I didn't see any practical way to try to import the various drawings from their online PDF. I slightly changed the layout of the parts that aren't the end pieces due mostly to rookie mistakes during practice cuts in pink foam. The foam sheet isn't a full 96" long so some parts fell slightly off the far end - I'd tweaked the layout to make it all fit before figuring out the foam was 3" too short and never got around to putting it back to the original format since it really wasn't critical.


At my buddy's request, I added a hand-hold cutout in the tops which makes them much easier to tote around the shop.

After the first set, I extended the length of the supports to match the tops and shelves (plus added dados for the supports). That helped get around a problem with cheap plywood not having a consistent thickness - which made the original supports have gaps at the ends during assembly. It also makes assembly easier as it helps lock the ends in place while you're getting the first clamp attached so screws can be installed.

This was a more complicated than I expected but I learned quite a bit about VCarve Pro, ShopBot, etc. The end results work really well though I'd hesitate to suggest this to any other rookie as a first project. :)

As the terms of use for Woodsmith Shop's file don't allow distributing modifications, I don't think I can post my VCarve Pro files. I can post a shot of the pieces being cut…which is enough to see the changes vs. their original design.

These were cut using a 1/4" down spiral end mill from Centurion Tools (which I learned about while lurking in the forums here). I was limited to 8K RPM for the first set (ShopBot owner's limit). The most recent set was cut at 12K RPM (owner revised their rules) and 4.5 or 5 ips, 1/4" depth per pass.

Thanks for the great info in the forums here. I've definitely learned faster than I would have on my own.

Tim S.

gc3
07-06-2011, 10:48 AM
Nice job, congrats on your first project! Can you share the .sbp file or a dxf?

gene
07-06-2011, 05:13 PM
They look nice . Should be quite handy and all store one atop of another

wberminio
07-06-2011, 05:53 PM
nice! It's just the beginning!

TimS
07-06-2011, 06:14 PM
Nice job, congrats on your first project! Can you share the .sbp file or a dxf?

Thanks!

I'm trying to get permission from Woodsmith Shop's parent company to post the drawing and tool paths. So far, no response after two attempts through their web site. I'm debating whether they're ignoring me in hopes I'll just go away or if the feedback/contact-us portions of their website aren't connected to real people (which is more likely in my opinion).

I'm reluctant to post the drawing otherwise since I don't want them to claim I've modified their intellectual property (even though posting it here would clearly be non-commercial).

The tool paths potentially could be posted though they're less useful without access to the drawing (to easily make changes/corrections).

Currently, the project is split into multiple tool paths rather than one big one that does everything. The tool paths are split into:

- dados and rabbets for the original ends, tops, and shelves

- dados for the now-longer supports (three new small dados in each end piece)

- handhold cutouts (pocket cut so I didn't have to drill yet another set of holes to keep the waste plug from causing problems)

- profile cuts for the shelves

- profile cuts for the tops

- profile cuts for the supports

- profile cuts for the end pieces


Splitting it up like that made it easier to fine tune a specific component without re-running the universe.

Total cut time is about 45-50 minutes for everything while some of the individual tool path files are only about 4 minutes long. So, re-running a 4 minute cut after making a change was much faster than sitting through nearly an hour of cutting.

We're limited to 4 hour blocks of time on the ShopBot so I wanted to have as much flexibility as possible while getting this to work.

In the end, the legs were the trickiest piece since they're the heart of the stacking/locking feature. I ended up having to do a bit of node editing on the insides of the legs to dial in just the right fit.

When I've done similarly complex items in SketchUp, I make generous use of components so a single change automatically propagates across all instances. I haven't found an equivalent feature in VCarve Pro. So, node-editing the end pieces meant either doing every change 8 times or deleting seven instances, creating seven new copies, and recreating the tool path vector selections.

If I can get permission to post the drawing and tool paths, I'll add them to this thread.

Tim S.

TimS
07-06-2011, 06:22 PM
They look nice . Should be quite handy and all store one atop of another

They stack really nicely! I've seen people standing on them when the sawhorses are stacked two-high (though I don't think I'd try them that way) and I've seen an amazing amount of weight piled on top of 8 of the horses (20+ full sheets of 3/4" MDF that was being glued together in pairs for work surfaces).

Once we got the inside of the legs and the tab dialed in, they slip together pretty easily. Two of the sets were made on-request for the place that owns the ShopBot I'm using. They provided one sheet of plywood and I provided the other (I didn't like their stuff after making one set, so I splurged on better plywood for the last set).

The buddy that originally asked if these could be done on a ShopBot laser engraved the ends of the set made from the nicer plywood before we assembled them. I've attached a shot of that set stacked up next to two of the first-generation version we made for the buddy that suggested the project.

I have an ever-growing list of additional project concepts I'd like to try on the ShopBot. Some are intended to push my knowledge of hold-down techniques while others are simpler "gee, how long would it take to do this on a ShopBot" ideas. :)

mick40
07-06-2011, 09:15 PM
Tim how about just posting the dxf file?

Mick

TimS
07-07-2011, 03:28 AM
Mick - the .dxf file is essentially a modified version of their drawing in the bottom right corner of page three (of the document pointed to in my original post). Their terms of use don't allow distributing modified versions, hence my reluctance to share until I get their blessing.

Maybe I spent too much time in manager training sessions but I'm getting progressively more allergic to lawyers as I age. I don't want them to slap the site with a DMCA take down notice (which I've seen abused by others on the web).

This is one of the rare instances where I prefer to get permission first rather than forgiveness later.

Tim S.

Brady Watson
07-07-2011, 08:16 AM
These have been around for over 10 years & go together without screws or hardware: ShopBot Sawhorses via 100kGarages (http://projects.100kgarages.com/viewitems.php?id=2&image=1)

-B

bleeth
07-07-2011, 09:46 AM
That's true but they are not nearly as strong. Way too easy for the legs to flay with no lower bracing.

Brady Watson
07-07-2011, 11:29 AM
I've got steel horses...so I never made a set of them. Thanks for pointing that out though.

Oh...I forgot to add last post:

Tim - Nice job!

-B

TimS
07-08-2011, 05:04 AM
These have been around for over 10 years & go together without screws or hardware: ShopBot Sawhorses via 100kGarages (http://projects.100kgarages.com/viewitems.php?id=2&image=1)

-B

Interesting alternative version…thank you for sharing it (and for the followup note).

The PDF I gave the URL for at the beginning of this thread was based on one of Woodsmith Shop's sister companies having run those horses as a print article in the late 90's.

Now I'm curious which came first. :)

The short size of these makes them surprisingly handy and popular. They're a good height for bench seating in the shop, toss a spare bit of plywood on them for a low assembly table, stack them two-high for a normal height assembly table, etc. They've surprised me in their utility and sturdiness.

Tim S.

TimS
07-13-2011, 01:43 AM
<snip>
If I can get permission to post the drawing and tool paths, I'll add them to this thread.


It was cleaner to create a new thread to post the files. That made it much more likely that the copyright statement they asked for would be seen.

Anybody looking for the files can find them at: http://www.talkshopbot.com/forum/showthread.php?t=13360

Thanks everybody for all the support above!