Making a rip fence system.

[Harvey Melvin Richards]

Dave, I think you are on the right path by not trying to copy a Bies. If I were making the fence with the parameters that you've set for yourself, I would use slip fit dowel pins to align the fence with the Thomson bearings. By removing 4 fasteners, the fence would come off and leave you with a clear saw table with nothing protruding up.

[Mike Schuch]

It looks like everyone else is doing a good job in steering you in the right direction. I have two SSR20 (kind of shaped like an I beam) linear rails 7' long and bearings in the attic which were going to be my fence before I stumbled across a cheap Vega. So I have pondered your idea many times.

I agree on the T concept and it sounds like you are on board with that. Even sturdier than a T configuration would be a box configuration. 2 bearings on the front and 2 on the back. My thinking on the box configuration is it will keep both the front and rear of the fence from deflecting. Kind of a double T fence. My plan was to use a piece of C channel I have lying around (http://www.engineersedge.com/standar...properties.htm) that is about 6" tall with about 1 1/2" flanges laying down with the 6" face against the table. Then just bolt the bearings to each of the 4 corners. Adjustment for square would be accomplished via a little play in the bolt holes on the C channel.

I like your lock, simple and effective.

Have you considered using some angle iron or square tubing rails inside of your 1" linear bearing rails to hold the top pieces of your saw together and then adjust the 1" linear bearing rails off of these rails for parallel? This would also give you a place to mount a measuring tape. Maybe someone else already mentioned this... sorry if it is a repeat.

If you are going to use bearings that fully encircle the shaft and the shaft is mounted at each end how are you going to remove the fence?

Here is a thought... 2 bearings on the front, 2 on the rear. The bearings on each rail are connected via a 1" x 1/4" piece of flat bar 6" long in my case that has slightly oversize holes for alignment. Then the flat stock has 2 alignment holes at each end and a center threaded hole. The Fence itself would have alignment pins on each corner and wing bolts (or similar to your threaded locking handle) in the center to secure it to the 1" flat bar.

This would allow alignment via adjusting the flat bar. Two threaded handles would allow for easy removal of the fence. The alignment pins would allow for quick reinstallation of the fence without having to square the fence again. The top of the C channel would give you great potential for making jigs. Sacrificial faces of multiple lengths could be easily mounted and removed. The bearings would never have to be removed from the rail (This will make your life easier). Just a thought!

If you don't already have the linear rod look into the SSR20 linear bearings. They allow mounting points the full length of the rail.

[Mike Schuch]

It looks like everyone else is doing a good job in steering you in the right direction. I have two SSR20 (kind of shaped like an I beam) linear rails 7' long and matching bearings in the attic which were going to be my fence before I stumbled across a cheap Vega. So I have pondered your idea many times.

I agree on the T concept and it sounds like you are on board with that. Even sturdier than a T configuration would be a box configuration. 2 bearings on the front and 2 on the back. My thinking on the box configuration is it will keep both the front and rear of the fence from deflecting. Kind of a double T fence. My plan was to use a piece of C channel I have lying around (http://www.engineersedge.com/standar...properties.htm) that is about 6" tall with about 1 1/2" flanges laying down with the 6" face against the table. Then just bolt the bearings to each of the 4 corners. Adjustment for square would be accomplished via a little play in the bolt holes on the C channel.

I like your lock, simple and effective.

Have you considered using some angle iron or square tubing rails inside of your 1" linear bearing rails to hold the top pieces of your saw together and then adjust the 1" linear bearing rails off of these rails for parallel? This would also give you a place to mount a measuring tape. Maybe someone else already mentioned this... sorry if it is a repeat.

If you are going to use bearings that fully encircle the shaft and the shaft is mounted at each end how are you going to remove the fence?

Here is a thought... 2 bearings on the front, 2 on the rear. The bearings on each rail are connected via a 1" x 1/4" piece of flat bar 6" long in my case that has slightly oversize holes for securing the bearings to facilitate alignment. Then the flat stock has 2 alignment holes at each end and a center threaded hole. The Fence itself would have alignment pins on each corner and wing bolts (or similar to your threaded locking handle) in the center to secure it to the 1" flat bar.

This would allow alignment via adjusting the flat bar. Two threaded handles would allow for easy removal of the fence. The alignment pins would allow for quick reinstallation of the fence without having to square the fence again. The top of the C channel would give you great potential for making jigs. Sacrificial faces of multiple lengths could be easily mounted and removed. The bearings would never have to be removed from the rail (This will make your life easier). Just a thought!

If you don't already have the linear rod look into the SSR20 linear bearings. They allow mounting points the full length of the rail. If you already have the rods and bearings... never mind, they should work fine.

[keith micinski]

I kind of like the idea of both bearings up front like a t style fence but I must admit I was also wondering how much flex there would be with the bar being anchored only on the ends. So for that reason I think you should stick with your design. Hopefully you get building soon so we can see some photos.

[dave pant]

Im anchoring it in 3 spots on each side. Today I got the bearings and spent 3 hours just drilling 3 holes heh.

[keith micinski]

Isn't
the third spot going to interfere with the lock down mechanism you designed?

[dave pant]

It would have but I decided to do this instead. linearbearingfencenew.jpg

[johnny means]

Manufacturers use solid stock because it is much stronger. Hollow bar is not stiffer than a identical diameter solid bar, not even close. Hollow forms being more rigid only applies when equal masses and lengths are used. In other words pound for pound hollow forms are stronger but they don't compare to an equal sized solid form that weighs 50 times as much.

[Chris Parks]

Manufacturers use solid stock because it is much stronger. Hollow bar is not stiffer than a identical diameter solid bar, not even close. Hollow forms being more rigid only applies when equal masses and lengths are used. In other words pound for pound hollow forms are stronger but they don't compare to an equal sized solid form that weighs 50 times as much.

Not what I have been led to believe by engineering people but I will defer to your greater knowledge. It really is not a factor in the short lengths we are talking of due to no vertical loading. When was the last time a fence rail/slide was seriously loaded? I guess the real reason solid is used is that it is cheaper to manufacture.

[dave pant]

I dont think a solid bar is weaker but i do believe it has less strength per weight ratio. Think about it. A solid bar IS a a hollow bar with smaller hollow bars inside of it.

[Chris Parks]

The strength is irrelevant in your case due to no loads being applied. The only thing it must nor do is deflect under its own weight and that is not likely to happen. I would use a hollow section as I like to keep things light.

[dave pant]

I got Thomson hardened linear shaft for free so Ill use that =)

[keith micinski]

It would have but I decided to do this instead. linearbearingfencenew.jpg

Boy am I glad that I didn't waste a bunch of time trying to do a sketch up drawing of tha exact idea like I was going to. If you are going with a point in the middle it would tempt me to want to try and make it a t style fence and just go with a front rail. That having been said I think your way will work great and be a really cool fence.

[dave pant]

SSPX1837.jpg

Still have to build the fence part and do get some hardware.

[dave pant]

Ok I put the fence together and it didnt work out that great. I then got the 2 bearings from my buddy and added them and put a space of about 3 inches between them and it made a huge difference. I am very very excited to get this finished but I have to wait till monday. It moves so smooth and no deflection at all! Right now I am using some wood for brackets because I couldnt wait till monday to make some out of steel heh.

I also put on the Wixey and that thing is so sweet. I do see the need for a micro adjuster now though haha!