Oh no, not another router!

[limbo]

After playing around with my current router for over a year I think I've gathered enough excuses to start building a new (3rd) one. This one should have:
-larger travel: 24" by 48" to fully access standard plywood panels.
-vacuum hold down for those bendy balsa sheets that follow your bit wherever it goes.
-rack & pinion on X and Y
-supported rails on X to finally be done with the sagging.
-a nicer color (hey, I do need excuses)
Although it will probably not be the fastest build, I thought it would be nice to start a build log. All comments en suggestions welcome!

Here's a pic of the frame being assembled and result:

greetings,
John

[jimini]

I see by the picture that you're starting at a good, young age. lol

[limbo]

Originally Posted by jimini I see by the picture that you're starting at a good, young age. lol

Yes, but my daddy is helping me a little.
Here's a bit more progress and a sketch of the gantry. The steel tubes that serve as X-guides are bolted down every 20 cm's. After having screwed together the frame Ynneb's saying "more bolts than the Sydney harbour bridge" popped in my mind a few times. I can imagine his complete machine must have a factor more...

John

[lurch]

A very nice start!! Simple, and clean, a good design. One question what keeps the x axis trucks from lifting under a downward load?

[limbo]

The only thing that keeps the gantry down is gravity. The gantry on my current machine weighs around 30kg, so I'm expecting this one to be around 50kg. I'm sure my router will not be able to lift that. (In fact, I hope those cheapo skate bearings will hold up.) The bearings are spaced far apart (28cm) while the gantry is as low as I could get it. The centre of gravity is mid betweed bearings and only some 12cm above the rails, so that a sudden stop after a rapid move will not cause the gantry to fall over.

John

[Hobbiest]

Originally Posted by limbo . (In fact, I hope those cheapo skate bearings will hold up.) John

unless you got the cheapest bearings money can buy (which they don't look like) they should be fine. A skateboard uses 8 bearings, and I have known skaters who weigh 300 to 400 pounds!

[limbo]

They are labeled ABEC5-608something. I dont think they are very good quality though. Brand new out of the box they have some play in them. Not side to side, but I can vary the angle of the inner ring w.r.t. the outer ring a bit by taking the bearing in one hand and holding the inner ring between thumb and finger of the other hand. Is that normal? They don't seem to have any play in axial or radial direction.

John

[cnc2k]

Anyone know best why to drill linear holes a steel rod?

[Ferenczyg]

Originally Posted by limbo They are labeled ABEC5-608something. I dont think they are very good quality though. Brand new out of the box they have some play in them. Not side to side, but I can vary the angle of the inner ring w.r.t. the outer ring a bit by taking the bearing in one hand and holding the inner ring between thumb and finger of the other hand. Is that normal? They don't seem to have any play in axial or radial direction. John

IF I am not in a mistake skate bearings are from abec-1 to abec-7 in uneven numbers, being better for higher number so yours are at least on the good side

/F

[limbo]

Hmm, I found a few old abec3 bearings in my scrap box and they have no play at all. Now I know why these abec5's were so cheap.. Oh well, I'll look at it from the positive side and say that some play is necessary to cope with misalignment in the bearing trucks.

Its too cold in the garage to start longer projects like routing the gantry side panels, so I did a few quick jobs. I made some U shaped extensions that will increase the Z-axis stroke, and a quick test to see if I could make the gear pulleys myself. I'm amazed at how well they came out. The part is accurate within 0.2mm! The material is Trespa. Very strong and weather proof but easyer to route than aluminium.

John

[Mike F]

John,

What is Trespa? I have not heard of this material but it sounds interesting. Is this a trade name in the Netherlands?

What size are the pulleys and what belts are you using with them?

Sorry for all the questions but this is one of the great things about this forum - the fact that you can glean so much information so quickly and pose many questions easily.

Good looking machine by the way.

Mike

[limbo]

Trespa is the trade name. In the Netherlands it is commonly used in house building, to finish the sides of the roof and as panels below windows and so on. It doesn't need to be painted and will last forever, even in our climate. I've heard that it consists of layers of paper, drenched in resin, pressed together under high force at high temp. It looks a little like the old brown PCB boards, but I think Trespa is more dense and heavyer. Great stuff.

The pulleys are for 1/5" pitch toothed belts (5.08mm pitch), 9.5mm wide. There is 40T on the pulley which is 64.6mm (~2.5") dia. The stepper has a 10T pulley giving 1:4 reduction for the pinion drive.

John