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Since David Collins saddle mill has reappeared, does anyone know much about linear guide rails?

After his initial post a while back I became interested in building something similar but became overwhelmed in researching linear guide rails - which type is sufficient which translates to how much you have to invest? I suspect there is sufficiently accurate and durable product out of Asia for the application?

Any info and experience would be appreciated.

Thanks.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

bearing type, rail type, materials, and profile & length are the main cost drivers. check out mcmaster-carr for descriptions/pricing and then source elsewhere for some cost savings. mcmaster ain't cheap but their site has a lot of info to help out.

he chose his rails wisely as they are close to the best choice for his app. have a look here:
http://www.mcmaster.com/#ball-bearing-carriages/=wlf87g

Bearings were a big cost, which as much as I tried I could not skimp on without sacrificing quality. My first prototype used ball bearings, but with the dirty environment these became quite high maintenance. These are a coated slide bearing (a few hundred bucks just in these parts alone) which are just as precise and smooth, but much more resistant to dust and contamination. For something like this, I've not found any way to go cheaper on the bearings without immediately sacrificing quality.

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Eschew obfuscation, espouse elucidation.

Having done a little tool designing myself, including the required R&D I would imagine that economy of effort would dictate that those in need of a tool with the precision of Dave's device should buy one, he's done all the work, not to mention he should be rewarded for that effort $.02

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Ken Cierp

http://www.kennethmichaelguitars.com/

I agree Ken, but I have no desire to rip off David's design with all of it's well thought out features - micro adjusters, laser alignment, vacuum hold down, etc.

I just want to mount a router on a set of guide rails, which I'm trying to get more info on.

So if anyone else has info or experience with guide rails that they are willing to share, I'd be grateful.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Kevin, look into 8020 aluminum extrusions, which have some linear guides that can be adapted for that use. I'm planning on making a sliding table for my table saw with that arrangement...

http://download.8020.net/2012_Product_C ... log_18.pdf

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Kevin,

A Google search for "linear bearings" will give you tons of info.

Steve

For anyone interested, I have some German-made Isel linear rails and bearings I need to clear out of my garage. PM for details.

For these applications, just about any supported rail linear bearing will get the job done. (unsupported rails will probably get the job done too but they're harder to mount)

When it comes to supported rails, there's pretty much two categories - round rail and profile rail. The round rails have a rail with a round section supported on one side. Profile rails have sort of a rectangular shape. Round rails are cheaper than profile rails.

Profile rails usually provide the same support irrespective of which direction the load is applied. Supported round rails cannot provide equal support in all directions because of the slot in the bearing to clear the support. The weak axis is the one in the plane of the rail and only in one direction. i.e. if you're pressing down on the rail you get full support, if you're pulling up you do not.

Profile rails are crazy strong! I can't remember exactly but I think Dave's device uses 10mm rails which are actually probably overkill for cutting saddle slots but once you go for the really small rails (I just ran a quick search and there are some really really small ones) the price starts going up.

The nice thing is that profile rails are smooth and very precise. I know exactly why Dave picked what he did.

What I would suggest is to search e-bay for surplus or cheapie linear rails with bearings around the length you're looking for. There will be a lot of them and they'll be pretty cheap and regardless of what you choose, they will definitely get the job done. SBR-xx are the supported round rail where xx is the diameter.

The other place you can check out is automation overstock as they've got pretty good pricing.

If you go with the profile rails, get the smallest ones you can find as they're kind of heavy and try to find them in the length you need as they are hardened steel and they're tough to cut.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I agree 100% with Andy. Most importantly, good rails are expensive, and if you are making a one-off setup you will be much better off shopping for surplus or scavenging parts from older tooling. We don't have that luxury, as the tool we're making has to be repeatable, which means consistently available parts, which means designing around sustainably available high quality parts. If you're only making one tool though and can build it around parts you find, you can often find some pretty good deals on rails and bearings through surplus dealers or places like eBay.

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Eschew obfuscation, espouse elucidation.

Check out Misumi for all sorts of standardized tooling components.

http://us.misumi-ec.com/vona2/mech/

Also check out dualvee rail and rollers from Bishop Wisecarver... I've been using that product for years (automation and machine tool design) in applications that need moderate accuracy but not the rigidity provided by profiled rails with linear bearings.

http://www.bwc.com/products/components- ... alvee.html

Also, in many low service applications, a gib slide can be used in place of roller bearing based solutions.

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David Radlin
http://www.facebook.com/radlin.guitars

Thanks guys, greatly appreciated!

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.