Gantry Router Log

[Rodm1954]

Like most newbies I have been reading the forum for months and have been inspired by the many variations and materials that members are building their routers from.

I have been building for a couple of months and now have something to show for the effort. Don't ask for drawings as they are in my head and change to suit the materials I have available and the problems I encounter as I construct it. I know this is a cop out but I would rather be making chips than drawing pictures.

The biggest hurdle was the electronics as I have very little experience other than how to solder. As this was going to be the critical component for me I decided to get the Xylotex board and if I could mount it and get it going the rest should be easier.

The box I got was not big enough to house the transformer and board so I got another one and put the transformer in one and driver board in the other.

Once I was confident I had everything working I got the 269 oz motors.

Here are some photos of the finished driver board and power supply.

cheers,
Rod

Perth, Western Australia

[Rodm1954]

So the electronics, motors and cables have been completed.

I decided to make the base from steel and the gantry from aluminium. My choice for a steel base is that it adds weight and stability and because it is fixed it does not require additional motor power.

I also wanted to have the rail supported laterally and vertically along it's lenght. The rail is 2 inch by 1 inch bright mild steel and is attached to the sides of the frame. The backbone and turnbuckles let me adjust one side without affecting the other side. There are slotted holes in the crossmembers to allow for adjustments.

Rather than waffle on perhaps if I post pictures it will be clear as mud for everyone.

regards,
Rod

Perth, Western Australia.

[Rodm1954]

The bearing carrier contacts three faces of the rail and I will be able to get the fourth face of the rail when the lower gantry crossmember is fixed in place.

The bearing holders are adjustable so that I will be able to plumb the gantry as well as make minor adjustments to each bearing.

There will be a total of twelve bearings on each side.

The first photo shows the bearing carrier on the rail. Second is the bearing carriage and the last is one of the bearing mounts before it was painted. Skateboard bearing have been used.

Well that is about it for the moment. Next I will be making a frame to hold the router and at the same time I will strip down the base and paint.

Just ask if you want more detailed photos or descriptions.


cheers,
Rod

Perth, Western Australia

[Lionclaw]

It's looking great Rod. Your nicely organized and labeled driver box will hopefully encourage me to build one. I currently have my driver board hanging from the wires on my x-axis motor It's only a matter of time before one of those wires comes loose and fries the driver

[ger21]

Are you counting on the stiffness of the gantry to keep the baearings tight to the rails? It seems like the bottom bearings may be able to pull away, but if the entire machine is aluminum and / or steel, it might not be a problem.

What's the overal size of the machine, and working area? It looks about 4 ft long? If it ends up as heavy as it looks like it might, I think the Xylotex might be a bit underpowered. But if it is, you can always sell it and upgrade later if you need to. It will certainly run the machine, you just might want to upgrade for higher speeds later.

Looks good, though. Keep us posted.

[Rodm1954]

Lionclaw
The labels are for me to remember the details of the unit and where to plug everything in.
Apart from my poor memory if you live in a remote part of the world it can be very inconvenient and expensive to send bits off for repair.

[Rodm1954]

Gerry,

The dimensions are X 28 inches, Y 39 inches and Z ? at this stage. I have probably got X and Y mixed up but these are the base dimensions. Base is steel and gantry will be aluminium.

As you have pointed out I too have pondered over the lower bearings maintaining contact.

Tests today seem to work OK with just two ali flats clamped between the bearing carriers. The bearing rails are 1 inch square and the plate they are attached to is 3/8 inch. The sides of the gantry will be 3/8 ali and will be fixed to this plate so there will be 3/4 inch ali over the bearing carrier. Fingers crossed at this stage. I plan on fixing 40mm (I gave up on the conversion to inches on that one ) ali angle iron to the gantry sides as well.

It would be better to have the gantry cross rail below the lower bearings and if needed I can do this as a major modification later.

My lead screws are 1/2 inch single start 6TPI acme threads. This was the only acme thread I could get locally after days of enquiries. The 6 TPI doesn't convert to linear very well but it will do for starters. It has a double bearing at the motor and single on the other end and I have turned up my own version of AB nut. Half of it is sitting on the photo of the base unit but it is not tested yet so more later. I agree the Xylotex might be a bit light but it gets me started and at over $AUS600 shipped it was all I was willing to pay at this stage.

It is expensive over here with low conversion rates and shipping costs. I got burnt for $AUS300 on ebay for a set of supposedly new Z axis linear rails so I am still recovering from that mistake. Description was new but no warranty and I blame myself for not being wiser. :frown:

A feature I forgot to mention is that with this design the the bearing rails will be fully covered by the table so I should not be getting bumps from the bearings running over sawdust.

I have a long way to go and appreciate any suggestions offered.

Here is another photo of the base adjusting thingo.

[ger21]

40mm = ~1-9/16"

$600 for a Xylotex I'm using a Xylotex for cost reasons as well, even though I'd rather be using Gecko's.

Don't worry about the 6tpi. Once you set up the software, it doesn't matter what the lead is. How long does it take to adjust all those bearings?

[Rodm1954]

The bearings are very easy to adjust and have the added advantage of allowing me to square things up. I have tapped the bearing holders so it is simply a matter of holding the bearing against the rail and tightening the bolt.

Before we converted to metric I was brought up on imperial measurement. My rules and tapes have both measurements and I work in both units. I visualise imperial for most things even though it has been forty years in metric for us.

The conversion was strange because for a long time they still made imperial sizes and just nominated the nearest mertic equivalent.

I just realised I have just highjacked my own thread.

Thanks for the heads up on the 6TPI.

[Rodm1954]

Gerry
I have taken up your advice on the support for the bottom bearings. What I have done is flip the ends so that I now have 2 inches clearance under the base. This will let me extend the gantry sides below the base and I can fix another cross piece between the gantry sides. This means one cross piece above the bearing carrier and one below.

I have also had a look at using screws to push the bearing pivots to make adjusting easier. I will include this when I rebuild it this weekend. Last weekend I built the bench to mount it on and I will paint all the bits and re-assemble it on the new bench. I got my X axis rails and bearings yesterday and are very pleased with them. 20mm shaft and four slide bearings and mounting blocks. I have a complete Z axis assembly with ballscrew in transit. With these components once I build the gantry it should progress much quicker than I had anticipated. I will post some more pictures after this weekend.

What I would like is some advice on a method to allign both rails during assembly. With all the adjustments I have incorporated I have the potential to make this machine very accurate but I can't think of a foolproof way to make both rails parallel and on the same plane. It would be very easy to build a machine with a twist in it.

Any suggestions would be really appreciated?

[Rodm1954]

Progress is slow but moving forward. I built a bench to mount it on and have pulled it apart and painted the steel.

I modified it by reversing the ends to lift the base off the table so I could attach a lower cross member. The gantry is finished and after a bit of adjustment it rolls very well. To make it perfect I need to adjust the rails slightly to make them parallel but I ran out of time tonight.

We are now into our summer and it is becoming too hot for daytime work so it has started to become a bit of a chore. I am hoping I will spark up after I attach a motor and see some movement.

A few pictures to update the thread.

[Rodm1954]

I pulled the gantry apart again and bored a couple of holes to reduce the weight.

I finished the adjusters for the bearing which has made it very easy to align and adjust the gantry. I am pleased with the gantry - smooth and no play or racking along the entire travel.

AB nuts are now finished and seem to work well. I machined two flanges and welded the stock nuts inside the flange. Springs between the plates keep the set screws tensioned.

Next step is to mount the acme thread and attach a motor for some movement.