CNC

Making a training hangboard

Used tools, methods and technologies:

CNC
Hand hrinding and wood postprocessing
Wooden board - 18mm thick

I did small CNC before in projects blinking hexagon and mainly SoundWizz but now its time to think big. Lets make a training hangboard.

Original CAD design and render.

CAM preparation screenshot

CAM

I gathered designs and mainly references of dimensions from the internet and my favorite climbing shops. Then it took me around 90 min. to have a final model in Fusion 360 and about the same to get used to and prepare the model in CAM for manufacturing. ¨ First model counted with 15 mm plywood but there was only 18 mm anviable so I just changed few parameters change Fusion to make it from just 2 layers of 18 mm one.

I used a 4, 6 and 8 mm pocketing tools for the main holes, a tip of 10 mm spotting tool for small indication of where to drill and chamfering tool. The project was done on a big 200x400 cm plywood board together with many other projects, so I don´t have exact time it took to make.

CNC machine used for the projects. Its an portal machine with vacuum bed and automatic tool swaping.

View of the live CNC process. Gcode is pregenerated in a computer and this is just for checking. The actuall project seen is someone else.

Automatic tool swap system is very elegant, using hydralics to pop up into the work area and then out of it again. Its very loud process, since high presure air is used to clean the tools

The two raw parts turned out great and it was time for drilling, gluing and general post-processing.

Drilling

Most of the time of handworking on this project was consumed by drilling. I used a setup on the image, a drill on a sliding axis with lever contolling the height. There are 4x basic M4 through holes for attaching to wall on the bigger part and a set of two M5 through holes on both parts that are for connecting bolts. I had to allign the parts, clamp them togheter and drill it on one go to make them preciselly the same. The bolts also have a pocket on their head done on the CNC. But pocket for the M5 nut from the other side had to be done manually and I used combination of a 10mm drill and 12 mm drill to make it. The setup uses an adjustable stopper to stop the drill at certain depth. I measured the depth very pedanticaly using a caliper and was rewarded with perfect results but it was slow. Then I found out a method of using a reference to adjust the possition of the stopper and it worked fast and great. See pictures below:

The more clamps, the better! The last thing you want is the part sliding a milimeter away just before you touch it with the drill.

Using caliper to measure the depth when the drill tip is touching the board, then adjusting the stopper height and measuring it at the same time? Slow and sketchy.

Elegant way of depth adjusting! I present to you: The Nut method! Plus the small pad for tolerance. This works fast and well. 11/10 JVC students recommend.

Chamfers

Chamfers, unlike fillets and raw edges are smooth and prevent splinters which is very good for a climbing board. These were done using a special chamfer-making tool. Spining bore-like drill makes perfect chamfering. The key is to do it slowly and just a small force should be aplied. I used marking to make the chamfer end on the exact spot where top layer of the board meats the bottom one for a smooth transition. You dont want to do the chamfering on the edges where both part are going to touch! So not on the side and also not inside the holes on the bottom board, that go through to the top one! It helps when the model and raw part has fillets inside the holes. It is less material for me to take off and it was clear where to do it.

To see the difference: Top half of the hole is chamfered, the bottom one is just fillet from the CNC.

The point of contact. On the right, there will be a chamfer up to a small mark just before the connection. On the left from that mark, raw edge is left for post-pro.

Set of drills used for the drilling part. 4, 5, 10 mm and 12mm spotting bits.

Gluing and postprocessing

Two M5 30mm bolts along with nuts and pads are used for securing both boards together. This alone would be enoough, but for extra endurance and smooth connection, I used a PVA (polyvinyl acetate) glue. First I tested the bolts that they properly and tight connect the boards, then unjointed it again and coated only the connection planes with thin layer of glue. Then jointed the boards again with bolts and tightened with decent force. The bolts work great to bond the boards and also secureing a perfect fit. I used a paper tissue to clean the overflown glue from the fresh bond.

After a short wait for the glue to harden, I used a combinantion of sanding tools, dremel and small raspers to get to the final perfect state. I used a smoothing dremel bit to make edges of the holes even more spliter free and smooth.

Used parts: M 30mm metric DIN bolts, rubber-banded nuts and pads.

Hercules glue, by beloved

Result

Summary

This was a great manually demanding project. I love working with wood and it was a good practice and refreshing work on a school, where I usually do math, electronics and software. I do a lot of woodworking in my free time, from bridge over a forest river to small garden decorations. CNC machine brings me new oportunities for my projects. The CAM enviroment is intuitive but becoming familiar with it will take more practice. Next will be preparation of a base for my final project. As always, you can find this project´s files and many more on my Printables profile. See ya next week again deep inside software.