Bgriggs R&P Hybrid Upgrade mini Log

[bgriggs]

I decided to post a miniature version of my build log for the Rack and Pinion upgrade to the Joe's CNC 4x4 Hybrid. I won't be giving any super detailed descriptions but just enough to give you an idea of how easy the process was.

I am doing this because I really like the CNCZone community and I also Love the Joe's cnc community. Since Joe's site is a members only site, zoners miss much of the innovation that is happening daily on the Joe's site. The shear amount of information and entertainment I have gotten from Joe's site have been well worth the price of admission (plan set purchase).

Please feel free to ask questions about whatever interest you. I will not be giving the sources of products which I used unless those sources are common knowledge (Gecko, Hobbycnc, cncrouterparts, etc....).

Bill

[bgriggs]

To start with I previously built a Joe's CNC 4x4 Hybrid. The machine used leadscrew and flange bearings to move the steppers at around 300 inches per minute. I had roughly 52" of Y axis travel and about 49" of X axis travel. Unfortunately, the Y axis tended to bind in the last 2 inches at the front of the table. This was purely due to my building and not a fault of the design. Therefore, I tended to think of 50" as being the most dependable figure to use for travel.

My son Benjamin and I completed the table in August of 2009. I used MDF in many places that called for Plastic in the original design, because The router I used to make all the parts was unreliable and I didn't want to risk my expensive plastic sheets.

I was really happy with the Hybrid's reliability. I cut a few projects with the machine and was really enjoying myself with my new hobby. However, as I mentioned earlier, people are constantly innovating and I like life on the bleeding edge.

Bill

[bgriggs]

Several of the members of Joe's site (http://joescnc.com) began making noise about building bigger, faster versions of the Hybrid. Several folks mentioned that building a machine capable of cutting a 4'x8' sheet of plywood was what they wanted.

Big machines create several design and operations problems. Firstly, the machine has a long distance to travel from one end of the board to the other which takes time (over 30 second at 300 IPM). Secondly, the machine needs to be ridgid. Thirdly the leadscrews must not whip at high speed (meaning thicker leadscrews). Lastly, BIG machines take up BIG room.

I decided the latter reason was my single largest consideration. I didn't have room for a 12' long table in my garage, so I needed another solution.

One solution that satisfied all these needs was an upgrade to a Rack & Pinion drive system from http://cncrouterparts.com. A R&P system is capable of running at 1200 inches per minute (8 seconds from end to end). The gantry required little modification and actually ended up being lighter in weight. Lastly, R&P drives don't whip like leadscrews at high speed. The motors are geared 3:1 so they achieve high speed while still in the high torque area of the motors.

It also turns out that when you remove the leadscrews and associated bearings from the Hybrid, you gain another 12" of usable travel. My machine now reliably cuts a 62" piece, and with careful indexing I can cut a full sheet of plywood by sliding the piece further onto the table partway through the cut.

[bgriggs]

I cut new pieces to replace the existing carriages for the machine.

[bgriggs]

The cncrouterparts Rack & Pinion drives are a fine piece of engineering. The drives are relatively inexpensive and are very sturdy. When you compare the cost of the drives and rack to the cost of leadscrews and bearings the difference is less than $10. For me this was an easy decision, especially since I had a buyer for my used equipment.

[bgriggs]

After I built the new carriages I painted them with a little latex paint, left over from the latest house painting.

[bgriggs]

I used my machine to make some replacement plastic parts from HDPE plastic. The R&P modification requires many fewer plastic parts to complete (a few are missing from this photo).

[Jason Marsha]

Everything looks great Bill, keep up the good work.

Jason

[bgriggs]

Cncrouterparts site mentioned several site that sold Racks. I chose Mooregear for my racks because I had heard they give good service. I was glad to find that the rumers were true. Moregear gives great service. Diane, took my order and I had my racks in just a few days.

I drilled the mounting holes in my racks with a 1/4" drill bit and a homemade fence guide. Tedious but not hard.

[bgriggs]

Originally Posted by Jason Marsha Everything looks great Bill, keep up the good work. Jason

Thanks Jason,

I have already completed the modification. I just didn't see anything posted elsewhere. So I figured folks would like to see it.

Bill

[bgriggs]

After all the new parts were assembled and fit tested it was time to remove the old pieces from the machine. My Brother Drew was visiting from California and helped me with the upgrade. If fact half the neighborhood came over at one point or another in the build.

Removing all the parts took some thought because it had to be done in a specific order........ Or redone again.

[bgriggs]

After all the parts were removed, we spent some time removing all the hardware from the carriages and bearing blocks.