jgro Style CNC Build Journal

[ignatz]

I ordered the HobbyCNC kit on Monday (4-25-05) and started building a router based off of jgro's plans. I bought 1 piece of 1/2" - 4' x 8' and 1 piece of 3/4" - 4' x 8' Blondewood Hardwood. The total was $52.00. I had the store cut both pieces in half and then started cutting them to size. I hope to have some pictures posted after the weekend.

[ignatz]

I spent 5 Hours today cutting all the wood for my router. I managed to get the smaller cutting base glued and clamped before I ran out of brads. I found aluminium angle today at a local salvage shop priced at $9.50 / 8ft.. I also picked up a small bottle of Gorilla Glue for $5.00.

[ignatz]

Not much time to work on the router today but I did manage to build 80% of the HobbyCNC driver (1 hour), completed the support beds and drilled all the 1.5" holes (2 hours).

The jgro plans are great. Very easy to follow so far. The only change I would suggest to anyone planning this project is that I would make the table a little larger to leave less plywood scrap. I think there is enough left over material at this point that I could have made the bed at least 2' x 4'.

This is the first time I've used the Gorilla Glue. "Wow!" is all I can say. Very strong and the expansion is great. Glad I tried it.

Here are some questions I have if anyone has answers:

1. Where is a good place to find couplings? I tried the site jgro listed but couldn't find them.
2. Should I upgrade the 1/4" threaded rod to 1/2" ACME threaded rod?
3. Can I cut the 4 3/4" grooves on the table top with the router itself?
4. Is there any reason I shouldn't make a wooden box for the electronics?
5. Would filling the gas pipe with cement to increase the rigidity be worth the effort?
6. Would a RotoZip work as the router? What are the Pros and Cons?

[gmfoster]

Originally Posted by ignatz Not much time to work on the router today but I did manage to build 80% of the HobbyCNC driver (1 hour), completed the support beds and drilled all the 1.5" holes (2 hours). The jgro plans are great. Very easy to follow so far. The only change I would suggest to anyone planning this project is that I would make the table a little larger to leave less plywood scrap. I think there is enough left over material at this point that I could have made the bed at least 2' x 4'. This is the first time I've used the Gorilla Glue. "Wow!" is all I can say. Very strong and the expansion is great. Glad I tried it. Here are some questions I have if anyone has answers: 1. Where is a good place to find couplings? I tried the site jgro listed but couldn't find them. Have you tried cnc on a budget? http://www.cnconabudget.com/ 2. Should I upgrade the 1/4" threaded rod to 1/2" ACME threaded rod? I used 1/4 x 20 and it works but if you are using steppers a courser thread is really better. It is hard to get speed with the 1/4 by 20 and with out some speed router bits want to burn. 3. Can I cut the 4 3/4" grooves on the table top with the router itself? I would have to study the plans to say for sure but I suspect you could. 4. Is there any reason I shouldn't make a wooden box for the electronics? Your call but I would go with metal I think. 5. Would filling the gas pipe with cement to increase the rigidity be worth the effort? I don't think so at least not with out re-enfourcement in the cement. 6. Would a RotoZip work as the router? What are the Pros and Cons?

They have been used. Pros rather light and easy to obtain, Cons some questions about quality. But don't get to hung up on these details as the router is one thing that is easy to change after you get going.

[WP1]

I'm using a RotoZip RZ1 and like it so far.

The quality issue seems to have been with a previous design. The current RotoZip RZ1 is clearly labeled "by Bosch" and "re-engineered for improved durability and performance".

I particularly like the keyless three jaw chuck which make bit changes very easy and allows the use of drill bits up to 1/4" which is difficult with a collet system.

Pete C.

[ignatz]

gmfoster - Thanks for the help! It was much appreciated.

WP1 - I bought my RotoZip last September and it doesn't say "by Bosch" but does have a keyless chuck. Good to hear that you've had good results. I think I'll give mine a try. Thanks.

Today's update - I bought most of the items I was missing today and yesterday. Here's a price list:

(local Surplus)
28VAC, 10.7 AMP Transformer - $22.00
(eBay)
30 8x22mm sealed bearings - $17.00
(Mouser)
1 PacTek DM-4 case - $30.00
(McMaster)
1 White Delrin Precision Ground Blank 1/2" Thick, 2" X 12" - $15.21
1 1/2"-10 Acme Size, 6' Length - $23.10
1 1/2"-10 Thread, 3' Length - $16.19
9 Plain Steel Acme 2G Hex Nut Right-Hand, 1/2"-10 Acme Size - $16.47
6 Steel Semi-Precision Ball Bearing Flanged Open for 1/2" Shaft Dia - $34.50
50 Hardened Steel Standard Dowel Pin 1/4" Diameter, 1-1/2" Length - $10.23

I still have to find the nuts and bolts and pick up the gas pipe. The total spent so far looks something like this:

Electronics - $395
CNC Router - $170

[ignatz]

I bought the gas pipes and all of the #10 hardware last night. $40

I still need to buy Couplings and the 1/4 inch hardware.

[ignatz]

The parts I ordered from McMaster and Mouser showed up last Thursday (5-5-2005). That night I drilled all the holes and mounted the parts for the HobbyCNC driver. I still have to wire it up but I think that its 85% complete now.

The ballbearings arrived on Friday. I bought the 1/4 hardware for $27. I also bought some material to make couplings from a salvage shop for $7.50 and the material to make the Y-axis spacers for $2.50.

The weekend was very productive but I wasn't able to complete the router. I managed to drill all the holes for the base and the gantry. I cut all the grooves in the bearing mounts and Z-Axis but still have to drill the holes. I cut all the delrin but still have to drill the holes. I cut all the alunimum and drill the pilot holes. I cut the leadscrews.
The most time consuming steps have been making the 1/2-10 ACME tap and machining the spacers. The first batch of spacers I made had to be thrown out and re-made.

I think I am about 75% complete at this point and I have to say, this is the single hardest project I have ever worked on. I have pictures but need to resize them to post. I am a little worried that everything won't turn out... but we'll have to wait and see.

[Content Removed]

The following pictures shows all of the parts cut out and drilled.

[ignatz]

I reached a major milestone last night, I managed to finish cutting and drilling all of the parts and began construction on the various assemblies. Here are a couple of pictures that show the result.

[ignatz]

I stole a page from Gingery when it came time to make the Anti-Backlash Block.
Here are some shots that show the process.

[ignatz]

Here are some pictures of my failed attempt at making couplings and spacers. Only one of the three couplings shown will work. The spacers shown were re-made one at a time instead of trying to drill 4 at a time. This made a big difference. If anyone has any idea for an easy way to make 1/4" to 1/2" couplings, I'd love to hear it. I tried cnconabudget but got no reply.

[WP1]

I'm assuming you don't have a lathe available since that would be the best for making the couplers.

On a drill press the best procedure would be:

Load your 1/4" bit in the drill press

Clamp your blank in the vice

Center the blank as closely as possible under the bit and secure the vise on the drillpress table

Drill the 1/4" hole through the blank

Change to the next larger sized bit, say 5/16 without moving the alignment of the piece

Set the depth stop on the drill press if you want

Drill a little less than half way through the blank with the 5/16 bit

Step up to the next larger bit and repeat

Work your way up to the 1/2" bit in as small increments as possible. This will help prevent the bit from being pulled off center as it might if you went directly to the 1/2" bit due to the heavy cut. When you get to the 1/2" bit, drill the last little bit to the half way point to clean up the bottom of the hole.

This should get you about as concentric as you're going to get without a custom stepped drill bit or a lot of hassles trying to align things.

Good luck.

Pete