JGRO or Solsylva?

[kiltjim]

First Post!

I am getting ready to build my 1st mill, and I am trying to decide which plans I should try. I managed to score 2 nice ACME lead screws with brass lead-nuts, and a whole bunch of bearings (FREE!!). And that doesn't even include the 2 servos (they don't match) that came with it.

The problem I see with this is that David Steele's plans call for 2 matching lead screws on the X-Axis, and a single screw on the Y. I would hate to 'waste' both screws on the X-axis, and use all-thread on the Y-Axis if I could avoid it.

I could go with the single screw plan, but I am afraid of flex. JGRO's plans seem more friendly to my situation, but lack the dual support of David Steele's plans.

Being an Engineer, I am also looking at modifiying Steele's plans, to use only 1 thread per axis, but the more I play with it, the more they look like JGRO's plans.

Any suggestions on which direction I should head? Or even other plans I should look at for inspiration?

[CurtisU]

I've adjusted my plans which are along the lines of Joe's or the JGRO to adopt the 2 screw approach. My reasoning was to avoid the "flex" of a single screw design. I don't have any experience with either, this is my first build, but it just seems right. A single screw looks like a weak link.

I'll have to get the added hardware for the "upgrade" but the expense won't be that great.

Curtis

[lgroulx200]

Hi,

I have built a modified Solsylva table and currently building the larger Solsylva machine.

The JGRO is a neat machine but the Solsylva will be able to do more things.

Larry

[HayTay]

Originally Posted by lgroulx200 The JGRO is a neat machine but the Solsylva will be able to do more things. Larry

Like what? Just asking out of curiosity. Is it "more things" or larger things?

I still have my sights set on the Joe2000che(vy) designed CNC router table.


Inquiring minds would like to know...

[lgroulx200]

[QUOTE=HayTay;212365]Like what? Just asking out of curiosity. Is it "more things" or larger things?


Hi,

The Solsylva small dual screw table can cut aluminum, both Solsylva machines can be set on top of your work and with proper indexing can cut unlimited size of stock.

The rails are supported so there a less of a problem of rail flexing like the JGRO machine.

These items allow the Solsylva to do things the JGRO can't do. If a persons requirments can be meet with the JGRO, they will still have a very good machine.

Larry

[Jason Marsha]

Just to add my bit, I built a modified JGRO with supported rails and tensioned sides which prevents my gantry from racking.
Either machine will do for a first build, you may then graduate to Joe's machine and then onto a larger machine if you wish.

Jason

[HayTay]

The Solsylva small dual screw table can cut aluminum, both Solsylva machines can be set on top of your work and with proper indexing can cut unlimited size of stock.

The rails are supported so there a less of a problem of rail flexing like the JGRO machine.[/QUOTE]

Thanks for the insight, Larry.

As to the unlimited stock size cutting by setting the Solsylva machine on top of the work, wouldn't the machine have to be screwed, bolted or clamped to the work to keep the Z-axis from lifting the Solsylva machine off of the work surface?

Also, in reference to the "proper indexing", sometimes it's difficult getting different cutting tools referenced to the same position for multiple cuts. I can't imagine trying to move the entire machine over a work surface and get it re-indexed properly to continue cutting. Your thoughts?

[bigz1]

Originally Posted by kiltjim First Post! I am getting ready to build my 1st mill, and I am trying to decide which plans I should try. I managed to score 2 nice ACME lead screws with brass lead-nuts, and a whole bunch of bearings (FREE!!). And that doesn't even include the 2 servos (they don't match) that came with it. The problem I see with this is that David Steele's plans call for 2 matching lead screws on the X-Axis, and a single screw on the Y. I would hate to 'waste' both screws on the X-axis, and use all-thread on the Y-Axis if I could avoid it. I could go with the single screw plan, but I am afraid of flex. JGRO's plans seem more friendly to my situation, but lack the dual support of David Steele's plans. Being an Engineer, I am also looking at modifiying Steele's plans, to use only 1 thread per axis, but the more I play with it, the more they look like JGRO's plans. Any suggestions on which direction I should head? Or even other plans I should look at for inspiration?

How about designing your own. Taking the best from various machines. I am building a dual screw machine due to a Y travel of 700mm.

Whats the worse that can happen? You end up with a better machine or you will have to rebuild it to someone elses plan.

Liam

[lgroulx200]

Hi HayTay,

You are right about indexing - it could be a real pain. Yes the machine needs to be screwed to the bench or work peice.

On the small dual leadscrew machine I built, I had to tap and drill over 40 screws for the z axis.

With that said, the machine is very ridged and cuts at a very good clip.

I am currently building David's larger dual leadscrew machine using my z axis from my first machine. This machine is much easier to build.

I am not very comfortable using wood 2 X 4's for the x axis rail supports and 1 X 4's for the other parts. I have some 2 X 2 aluminum tube for the rails and birch ply wood for the rest.

The machine is getting close to completion. I need to get a new driver board. I just moved and something must have come loose in the connections. When I plug the machine in, it produced some nasty smoke.

For me, the hardest part in making the router was actualy just starting. I was in the same position in trying to decide what machine to construct.

Larry

[kiltjim]

Originally Posted by bigz1 How about designing your own. Taking the best from various machines. I am building a dual screw machine due to a Y travel of 700mm. Whats the worse that can happen? You end up with a better machine or you will have to rebuild it to someone elses plan. Liam

That is what it looks like is going to happen. I am going to go with a single thread under the table (from JGRO's design) and a dual rail system similar to the Solsylva plans. I was trying to stay away from having to build a table like JGRO's, but I think it is going to have to happen.

[kiltjim]

Continuing on the topic of getting rid of the torsion table, I was looking at Joes machine, and wondering if I could alter his design.

Here was my idea:
Get rid of the leadscrew under the table, and move it to the outside. Put a matching screw on the opposite side as well. The only thing remaining under the table would be the "gantry bottom" torsion box.

My question to those with a machine is this:
Would eliminating this and building different bearing assemblies on the X rails that clamped around the bearings (instead of just on the outside) introduce too much flex in the uprights?

Joe shows 2x 1/2" MDF for the uprights, which could always be thickened for more strength, but without a machine of my own, it is hard to know how much stiffness is actually needed.

Any suggestions?