[CarveOne]

This is an engineering decision that is yours to make. Is the extra 2" of travel side to side more important, or do you want the little bit of extra stiffness that a wider footprint might (or might not) provide?

I have a 12' long homebuilt machine using early CNCRP R&P drives that has two 6' gear racks butted end to end with the teeth facing downward. I rarely need to do anything to the racks during cutting jobs. Fine dust collects on the top side of the racks when not in use for long periods, but not in the gear teeth. Anything you can devise that covers the racks and rails to deflect flying chips and dust will mean less diligence in keeping them clean during long cut jobs.

[stealthshooter]

did a bit of work on my Z model.

[Master of nun]

The tension method all looks very impressive and a great use of lateral thinking.......is it really necessary?
Don't think I'm knocking you, But how much is that going to cost?

You CAD skills are looking good!

[stealthshooter]

That setup will run me about $70 I can also go this direction which would most likely be cheaper and have a couple less parts but I'm not sure if it will be as maintenance free? What do you think I should run the tension at on the belt? If I go with the shock I'll need to know what poundage to order. If I go the other route I can play with it but I still wonder about reliability in the end. Opinions between the 2 setups?

SMC MXQ12 40CS Pneumatic Slide Table Cylinder | eBay

And thanks for the compliment! I really need to order the training DVD's because I'm sure there are commands that I don't know of that would make things easier. I am having fun though!

[Master of nun]

Ok, that's much cheaper than I thought!

Having the tension reliant on air supply does worry me a little though, the previous spring setup would be more fail safe.

I left my router running while I was out having a great time with freinds ( some 10 hr machining op.)....little known to me the Z axis pulley had worked loose. so the Z plunged through the table with a 12" x 3/4" tool and continued to make mince meat of my new vacuum table until it ran into the steel structure beneath....of which it had a good go at too!

long story short....do you want to be reliant on air pressure?

[stealthshooter]

I'm thinking the same. The air compressor could loose power or a hose could fail or or or.........I think the shock would be pretty reliable. I do need to find out what amount of tension needs to be on the belt and how much is too much!

[Master of nun]

The smallest shock listed in your earlier post was rated at 50-400N.....so close to 5-40KG force, I would think this would be sufficient along with some kind of one way rachet, so as belt stretches slack is taken up but, any rapid changes in direction wouldn't cause the shock to absorbe motion.

[stealthshooter]

I think I'm going to order them from Mcmaster carr. http://www.mcmaster.com/#gas-springs/=lfvdpc
Part# 9416K14 They start at 15 pounds then go to 20 pounds then 10 pound increments.

and for the rod ends McMaster-Carr

Do you have any ideas for the ratchet? I have one so far but not sure if it will work?

[stealthshooter]

A little more work today.

[stealthshooter]

Any recommendations for the concrete mix for my legs?

[Master of nun]

That's a tight space you have to work in there!

As for a rachet....I've done a little searching and can't come up with a simple off the shelf option, personaly I'd use a simpler setup with an idler to adjust the belt.



I filled my 4x4" legs with washed sand...as for concrete a mortar mix would probably do, although a heavier agregate would be denser. I filled mine through small holes so my options were limited.

[stealthshooter]

Yes it is a tight space! There is going to be a vertical beam removed and replaced with a header here pretty soon. That and another wall knocked out. That will make more room. What you can see is only about 1/3rd of the room but the rest of the room has my saws and such that my wife and I are still using. I figured I'd assemble it in the corner kinda out of the way.


Let me see if I can draw up what I'm thinking about as far as the ratchet. It involved modding the Gas strut but I really do think it will work. If it does I don't see why I couldn't use it in other applications like the 72" belt grinder I'm wanting to build.

[stealthshooter]

I was thinking something along these lines.

[stealthshooter]

A bit more.

[stealthshooter]

More progress