[4DThinker]

Until I retire in a couple of years, my clients are all college students. Most from my own class, but occasionally a student from other classes/sections. The help I provide is problem solving relating to how to connect the parts of their furniture designs.
The problem arises when working over email and trusting the information/drawings/dimensions provided by the students. Latest was just the last two days CNCing mortises and tenons to put together a complex set of leg parts for a small table.
Digital file arrives with no thickness information provided. I ask the student how thick the wood is her parts are cut from. 1.5 inches thick she insists.
So I draw up all the toolpaths needed. 11 in all. All assume that tenons and related mortises will be centered in the 1.5" thickness of her parts. I create a DXF file with outlines of her parts with allowances for all the tenons on their ends, and email her the file. Critical angles are documented. She is to print/plot the file, then spray stick drawings to her board blanks to cut out the shapes I'm expecting/relying on.

Jumping to the end I'll mention the parts all fit together perfectly, and her table stood up beautifully/solidly.

Backing up two days though I met her in the college fab lab to start cutting tenons on all the pieces using a Probotix GX2525 I have set up for for vertical and angled clamping of parts under the spindle. Left and right sides could use the same file/setup for a given centered tenon cut. Very first piece cut the tenon appeared to NOT be centered in the width. Correct distance from front edge. Tenon the correct size. A quick measure of two boards together showed 2+15/16" width where it should have read 3". Her boards turned out all to be 1/32" thinner than 1.5" thick.

Ultimately this meant I had to keep track of every toolpath making adjustments to where my X direction was homed to. Some tenons needed to be 3/8" from the back side. Some needed to be 3/8" from the front side. There was no room for a mistake here or her assembled pieces would not be flush.
After cutting a few pairs I realized lefts and rights were not exactly the same shape. Ends I'd homed to varied a little bit, meaning alignment of tenon or mortise from an edge would be different between the two parts even though they were cut using the same jig/setup. This meant every drawing I had needed slight movement of vector shapes to account for where they actually got cut on her parts. 1/32" was the common adjustment needed.

The lesson I keep relearning is that you can't trust a client/student to know precisely how thick a board is. Secondly, you can't trust a student to cut parts out exactly to shape even if you provide the precise drawing patterns to use. 😆

4D

 

[honesttjohn]

Heck, I can't get mine to come out right most of the time -- and I'm the planner, file maker, and customer.

 

[Oscar36]

@honesttjohn: Ditto.

@4DThinker: Too much math and I have a math degree. I do woodworking to escape the stress of life. All that work would double my stress. lol. But none the less very impressive work with the cnc router. I just make "purty pitures" with mine and call it good.

 

[4DThinker]

More about drafting skills than math involved in setting up complex joinery jobs. A former department head was sure I was using calculus though. Second to drafting would be the ability to take accurate dimensions off of student furniture parts. My current department head has his own shopbot CNC so he is sure any student could be trained in an hour or two to duplicate what I do. He doesn't realize I've been helping student helpers cut simpler profile/pocket job for students, but haven't found one yet that could even visualize how to go about setting up joinery cuts at compound angles on project parts. I have seen plenty of glazed over eyes when I move into that territory with a helper. Far easier to just handle those jobs myself. The new/young professors we have realized I'll be retiring soon and think they can duplicate the complex jobs I use a CNC for with a PantoRouter. I hope they can, but know their belief that setting up a PantoRouter for a complex job would be easier/quicker than setting up a CNC for the same job is a flawed assumption.

4D

 

[kp91]

It isn't just college kids....... we were doing major upgrades to one of our vessels in 2013, adding a lot of new environmental equipment. To get everything perfect, they hired a company to take laser measurements of the spaces so they knew exactly how much space was available, and where to put everything.

I got on and started looking at the proposed equipment arrangements and the manuals for the equipment, and realized they didn't include any of the required service areas of the machinery when they planned their layout. They made the equipment "fit" in the space, but we couldn't have operated or serviced it...... they got paid anyway....

sometimes we don't know what we don't know, or what details are going to be the ones to bite us in the butt. I have had many hard lessons that way. hopefully it was a good learning lesson for the student!

 

[4DThinker]

At least this student was curious about and appreciative of how I went about tweaking all the toolpaths/origin settings to accommodate her parts that weren't exactly what they should have been. Of particular delight was the look on her face when her table legs dropped perfectly into the mortises cut in the bottom of her table top. We stood it up to verify the wedge cut top was level on top after legs were installed. The wedge cut on a 2" x 16"x 32" slab of oak was done with the help of a student worker using our large Multicam CNC. Before it was done the student wanted to warn me the final top would be 31.5" wide as the student had not aligned the cut and 1/2" on the edge wasn't cut. With all my cuts based on a 32" x 16" top I assured her I could find a way to trim the remaining off using some other process in our fab lab. A flush trim bit on a router table did the trick with her slab held vertically with help from a square brace clamped to it.
4D

 

[DesertRatTom]

My late brother worked for several years for a big design firm as a prototype and model maker. He did a lot of projects for designers whose drafting skills were deficient and he had to correct the designs as he built the prototypes. This was 35 years or so ago, so computer design wasn't around yet. They did a lot of prototypes for a big office furniture company, and I recall him speaking about cross braces that were impossible, more like an Escher endless loop drawing, than anything else.

 

[4DThinker]

I started before computers were around as well, and neither were any tools that needed a computer to run them. My first job out of college was as a furniture designer. Although I knew how to make furniture by then the company I worked for didn't expect me to make things. Just draw them. They had a couple of fabricators who both made prototypes of what we drew up as well as machines to mass produce the parts efficiently. The marketing staff got to decide if they thought they could sell what I would draw up. If they did then prototypes were made and a production plan/cost estimates were figured out. If the numbers seemed reasonable then prototypes would be made for showrooms that hopefully would generate sales orders. What I quickly came to appreciate about the fabricators was that unless what I drew up violated a law of physics they could figure out how to make it. Then they would figure out how to mass produce it economically.
4D

 

[difalkner]

It happens in the commercial design world, as well. About 30 years ago when our new church was being built our music director specified a choir room that would seat 100 people. When the builders finished and we began setting up the choir room we could only fit about 60 chairs in the room. So we tried a different arrangement and still couldn't get 100 chairs in the room.

Then it dawned on us that the designer/architect didn't know squat about setting up a choir room with 3 or 4 curved rows of chairs nor did he ask anyone how a choir room should be set up nor did he do any research. We set the room up like a meeting room with lots of rows and lots of columns and sure enough we found in that seating arrangement we could easily fit 100 chairs.

 

[4DThinker]

Yep. I'm teaching in a relatively knew fab lab. After moving in we've discovered several challenges that no one anticipated even though we did have a chance to provide input on the design/layout. It is a basement/lower level space. and as we were concerned about it being dark and gloomy they made several window walls to help daylight from the few exterior light sources spread through the space. Nice, but you can't mount a bracket for bar clamps on glass wall. The specified glue room where clamps are most often needed has the most glass walls and the smallest percentage of solid wall. We also have always had a way to shut room lights off and pull down a backdrop to take well lit photos of student projects. Not possible during the daylight hours of the day now. For the evening hours there are security lights we can't shut off either. My dept head complains about the quality of project photos. Hard to do with no obvious place to set up a nice photo booth.

 

[RiovistaAndy]

Until I retire in a couple of years, my clients are all college students. Most from my own class, but occasionally a student from other classes/sections. The help I provide is problem solving relating to how to connect the parts of their furniture designs.
The problem arises when working over email and trusting the information/drawings/dimensions provided by the students. Latest was just the last two days CNCing mortises and tenons to put together a complex set of leg parts for a small table.
Digital file arrives with no thickness information provided. I ask the student how thick the wood is her parts are cut from. 1.5 inches thick she insists.
So I draw up all the toolpaths needed. 11 in all. All assume that tenons and related mortises will be centered in the 1.5" thickness of her parts. I create a DXF file with outlines of her parts with allowances for all the tenons on their ends, and email her the file. Critical angles are documented. She is to print/plot the file, then spray stick drawings to her board blanks to cut out the shapes I'm expecting/relying on.

Jumping to the end I'll mention the parts all fit together perfectly, and her table stood up beautifully/solidly.

Backing up two days though I met her in the college fab lab to start cutting tenons on all the pieces using a Probotix GX2525 I have set up for for vertical and angled clamping of parts under the spindle. Left and right sides could use the same file/setup for a given centered tenon cut. Very first piece cut the tenon appeared to NOT be centered in the width. Correct distance from front edge. Tenon the correct size. A quick measure of two boards together showed 2+15/16" width where it should have read 3". Her boards turned out all to be 1/32" thinner than 1.5" thick.

Ultimately this meant I had to keep track of every toolpath making adjustments to where my X direction was homed to. Some tenons needed to be 3/8" from the back side. Some needed to be 3/8" from the front side. There was no room for a mistake here or her assembled pieces would not be flush.
After cutting a few pairs I realized lefts and rights were not exactly the same shape. Ends I'd homed to varied a little bit, meaning alignment of tenon or mortise from an edge would be different between the two parts even though they were cut using the same jig/setup. This meant every drawing I had needed slight movement of vector shapes to account for where they actually got cut on her parts. 1/32" was the common adjustment needed.

The lesson I keep relearning is that you can't trust a client/student to know precisely how thick a board is. Secondly, you can't trust a student to cut parts out exactly to shape even if you provide the precise drawing patterns to use. 😆

4D

Sounds to me like she/they have a problem with the education they recieved. Whether it was you or a prior instructor it's obvious someone failed the student.

 

[4DThinker]

This was a student of another section of the beginning workshop course we teach. She had missed a few weeks of her own class due to having caught Covid19. All the wood she had came from her dad's garage where it had been stacked for several years and was in pretty ragged shape. She had joined and planed and glued up planks until she had enough to make the parts for her furniture design. She had a deadline to finish her project assigned by her own professor. I specialize in running our small CNCs to make complex joinery for all our students so she asked for my help. I don't mind helping any of the students but did expect her to have her parts cut out as I specified before I would cut her joinery details for her. You've read the rest of the story already.

This week summer school classes have started and I have 10 students taking the second class in our sequence. They have three full days to design and complete a small plant stand that can have any number of legs but not 4. The project is intended to get them quickly refreshed using our extensive fabrication lab. Two different students decided they wanted a triangle for the top of their designs, and both asked me how to draw a perfect equilateral triangle. I think they were a little surprised that I could show them three different ways to do it. I was a little surprised that they were in their 3rd year of college and didn't know even one way to do it.

4D

 

[RiovistaAndy]

This was a student of another section of the beginning workshop course we teach. She had missed a few weeks of her own class due to having caught Covid19. All the wood she had came from her dad's garage where it had been stacked for several years and was in pretty ragged shape. She had joined and planed and glued up planks until she had enough to make the parts for her furniture design. She had a deadline to finish her project assigned by her own professor. I specialize in running our small CNCs to make complex joinery for all our students so she asked for my help. I don't mind helping any of the students but did expect her to have her parts cut out as I specified before I would cut her joinery details for her. You've read the rest of the story already.

This week summer school classes have started and I have 10 students taking the second class in our sequence. They have three full days to design and complete a small plant stand that can have any number of legs but not 4. The project is intended to get them quickly refreshed using our extensive fabrication lab. Two different students decided they wanted a triangle for the top of their designs, and both asked me how to draw a perfect equilateral triangle. I think they were a little surprised that I could show them three different ways to do it. I was a little surprised that they were in their 3rd year of college and didn't know even one way to do it.

4D

Sounds like they missed Geometry in high school. And is amazing that she could not read the plans and measure and layout the necessary cuts. I don't think this can be laid off on COVID as these skills should have been taught to her much earlier.
Have a nice evening.

 

[4DThinker]

As for the part plans I sent a her a PDF of them to print out full scale, with instructions to glue them to her wood blanks using spray adhesive. That included to line up one edge with her joined board edge, then bandsaw the other tapered side followed by using the horizontal belt sander to sand to the line. For the ends then one needed to be square cut, and I included the angle the other end needed to be cut at using what I assumed would be our compound miter saw. Apparently she tried to use the Sawstop table saw with a miter gauge and she let the guide hit the blade which set it off. That sent her to the miter saw but she wasn't familiar with it so she eventually band sawed the angled ends and used the disc sander to sand them to the line. Only problem with band sawing then sanding is you have to pay attention and she apparently didn't know how to do that yet. Close, but the parts weren't exactly what they should have been. I also didn't see any residue or evidence of spray adhesive having been used.

 

[difalkner]

she apparently didn't know how to do that yet.

That reminds me of a sign I put up when I had my woodworking business where we did restorations and repairs to go along with the furniture design work we did. The sign simply said, "Shop rate $25 per hour, unless you tried the repair first, and in that case the shop rate is $45 per hour". It was the mid to late 80's and that was decent money for our area back then.

 

[4DThinker]

There's a good Idea. Been thinking about it already. Work is free if you provide info that matches the true dimensions of your project boards. If I have to make adjustments on the fly because you didn't then the rate is a flat $10 for each file I have to change. Of course the university discourages any profit making off the students. I'd love them to prove there is any profit made though as 1/4 the time I'm using my own CNC to cut student projects and have to pay for my own bits and maintenance. I had to swap out a router today as the one I was using to do a VCarve cut today died in the middle of the cut.

4D

 

[difalkner]

flat $10 for each file I have to change

That would be more of a tip than it would be for profit. But it might get their attention!

 

[PhilBa]

There's a good Idea. Been thinking about it already. Work is free if you provide info that matches the true dimensions of your project boards. If I have to make adjustments on the fly because you didn't then the rate is a flat $10 for each file I have to change. Of course the university discourages any profit making off the students. I'd love them to prove there is any profit made though as 1/4 the time I'm using my own CNC to cut student projects and have to pay for my own bits and maintenance. I had to swap out a router today as the one I was using to do a VCarve cut today died in the middle of the cut.

4D

The "tough love" approach is to reject the job and require that they resubmit with corrections. I don't know if you want to get a reputation as a HA but it will get you the behavior change you want.

Do you have a "How to submit a job" requirements document? You could put the rejection warning on it is big red letters.

Also Lab Fees are common in many University/College settings. Worth considering.

 

[difalkner]

To me it's kind of like when I went to college and had a class in Fortran; we had to keypunch our code into hundreds of cards and if there was one tiny mistake we had to redo the entire batch. Submit it with accurate code and everything worked as planned. An error meant do it over and bring it back corrected.

 

[4DThinker]

Before the college had a CNC but I had one I would have students bring their work to my house on a Saturday or Sunday morning. My CNC lived in an unheated garage but ran fine even when the temps were below freezing. One bitter cold Saturday morning I was up early getting the CNC warmed up, homed, and ready for 2 students I was expecting at 8:00am. No sign of them at 8:00. They finally rolled in at 8:45 where I caught them as they started getting out of their car to tell them I wouldn't be helping them that day. I gave them the phone number of a professional in town that could do their CNC work for a fee.
As for what to submit I tell each student asking for help exactly what I need. 15% of the time I get exactly what I asked for. The rest of the time I have to explain why what they sent won't work and have them resubmit.
As for fees, every student pays a technology fee for each hour they have enrolled in. It is used to pay for technology, but not faculty which I am. It buys the bits and sandpaper and tools. If I ask they'll buy replacements for my tools that I've worn out while using them for student projects. More often though I've payed for everything in my personal shop. I also clean up after my CNC is finished, which I don't do at the university. Each student I cut something for has to clean the area around the CNC we used.

4D