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Old 05-21-2015, 02:53 PM
bumpnstump bumpnstump is offline
 
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Default More brain sludge......

Thought I'd post one of my 'almost-but-not-quite' projects and see if someone can suggest how to 'fix' what I can't.

Ever since first using an EZ-1, I've wanted a quick set-up—and—adjust style of fence. Didn't want to use a table saw fence, and the Incra system was too cumbersome for me, so I settled on a simple design that many others use: straight piece of ply that is set parallel to the cut line of the track on the EZ bridge. Works great, and I'll probably never get too far away from it, due to it's simplicity and accuracy.

Still, my mind was searching for a better 'variation on a theme'.

What I came up with is shown in the pics. (Pic 1) It's a straight piece of 1/2" baltic birch that is attached to a pivoting hub, which is slid into one of the SMEs on my EZ-1. (I have an earlier model EZ-1, but the concept applies to the newer models.)

Pic one shows initial set-up: loosen the 4 clamp knobs at the hub; slide the fence/hub assembly up against the lowered EZ-1 track, making sure there is no debris between the track and the fence. While holding the assembly against the track, tighten the two levered knobs; then, tighten the two lobed knobs. You've now adjusted the fence to be exactly parallel to the track.

To use (pic 2), slightly loosen the levered knobs; slide fence assembly to the desired position and retighten the levered knobs. Theoretically, you should still have a parallel fence. Reality, tho, is that sometimes it is parallel, other times, it's out by a noticeable smidgeon (almost as much as 1/32"). The best I can determine regarding this error has to do w/the EZ connector that the assembly slides on doesn't always exactly re-center on the SME when it's retightened, allowing the possibility for a slight out-of-parallel situation. It's easily adjusted back to parallel, but I'm wanting it to be accurate every time, w/out checking.

I considered using spring plungers (see here: http://www.jwwinco.com/products/sect...pnl/index.html) on the bottom of the EZ connector that guides the assembly, but I have some screws in the way. (Yes, I could replace the SME w/a new, unfettered piece to try it out, and, I might do that some day.) The theory is that the spring plungers would keep the EZ connector up against the SME, reducing/eliminating the possibility for misalignment when moved and refastened. One thing I did do is shown in the components picture (pic 3). On the EZ connector (which I made as long as possible, to help re-center every time), you can see where I've routed out a bit of aluminum and inset plastic guides to help re-center the connector in the SME. This vastly improves recentering performance, but not 100%.

I'd love some 'outside' help on this, so please post your ideas. This fence adjusts quickly; removes/installs quickly from the SME; has 4-clamp lock-down (ie. secure; altho, once set and adjusted, I back up the fence w/a couple of EZ stops, just to make sure it isn't bumped out of alignment- see pic 2). Where it really shines, tho, is in taper cutting. Pic 4 shows a 6 1/4˚ set-up for some tapers I will be cutting. You can preset the fence to the desired angle before sliding into position, or, you can set the piece to be cut in the desired cut position and then adjust the fence to the piece- either approach works well.
Thanks,
Rick
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  #2  
Old 05-21-2015, 04:50 PM
tomp913 tomp913 is offline
 
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Rick,

It sounds as if there's enough tolerance between the connector and SME extrusions that the combination isn't exactly "self centering". Spring loading the connector up against the bottom of the SME may help but I'm thinking that it may not be 100% foolproof.

Here's an idea - since you like the Incra products so much :>), set a miter gauge slot extrusion into the panel in the top of your bench, get an Incra slider of the appropriate length and attach your protractor/fence to the top of the slider. The slider adjusts from the top for a tight/sliding fit in the miter gauge slot extrusion so would keep your fence parallel to the track. This assumes that the plywood panel is locked in position and doesn't move relative to the track - not really that familiar with the EZ1 and it's foibles. The only other thing to address is some way of locking the fence in position - how about a piece of connector in the SME underneath the fence with a knob that clamps one side of the fence to the top of the table. To set the fence, loosen the knob, move the fence/slider assembly to the required position and tighten the knob.

I looked at your photos again once I'd sent the message and saw that you have a piece of SME at either end of the fence - put the clamping knob and connector in each SME, this will give you positive lock of the fence and also eliminate the need to move the stops in place to hold the fence from being bumped (although I would still do that but that's me.

Sounds as if it will work.

Tom

PS Will be able to get back on Katie's project shortly (I hope).

Last edited by tomp913; 05-21-2015 at 04:56 PM. Reason: After thought
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Old 05-21-2015, 06:26 PM
bumpnstump bumpnstump is offline
 
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Quote:
Originally Posted by tomp913 View Post
Rick,

It sounds as if there's enough tolerance between the connector and SME extrusions that the combination isn't exactly "self centering". Spring loading the connector up against the bottom of the SME may help but I'm thinking that it may not be 100% foolproof.

Here's an idea - since you like the Incra products so much :>), set a miter gauge slot extrusion into the panel in the top of your bench, get an Incra slider of the appropriate length and attach your protractor/fence to the top of the slider. The slider adjusts from the top for a tight/sliding fit in the miter gauge slot extrusion so would keep your fence parallel to the track. This assumes that the plywood panel is locked in position and doesn't move relative to the track - not really that familiar with the EZ1 and it's foibles. The only other thing to address is some way of locking the fence in position - how about a piece of connector in the SME underneath the fence with a knob that clamps one side of the fence to the top of the table. To set the fence, loosen the knob, move the fence/slider assembly to the required position and tighten the knob.

I looked at your photos again once I'd sent the message and saw that you have a piece of SME at either end of the fence - put the clamping knob and connector in each SME, this will give you positive lock of the fence and also eliminate the need to move the stops in place to hold the fence from being bumped (although I would still do that but that's me.

Sounds as if it will work.

Tom

PS Will be able to get back on Katie's project shortly (I hope).
Tom, good suggestions. I'd actually thought about a similar approach, using one of the extrusions in the pic below, and might one day go that route. (Here are the extrusions: http://www.igus.com/wpck/3587/drylin_n) The track could be imbedded into the plywd. on my EZ-1, and the fence/hub assembly would be attached to the sliders in the track- no sideways movement and very smooth action.

I was hoping to keep this thing simple, and mostly EZ-centric in terms of materials used (well, not counting the wood, etc.). I agree w/you, tho, that the EZ connector will not give 'perfect' repeatable results- back to the drawing board.......!

Thanks,
Rick
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  #4  
Old 05-22-2015, 12:48 PM
sean9c sean9c is offline
 
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Totally impractical for the application but I always thought that cable/pulley system they used on drafting tables to keep the arm square when t was moved was slick.
Problem with a rip fence like that on a PBB is that it has to be perfectly parallel as any variation directly shows on your workpiece. Table saw fences only have to be sort of parallel the blade, a little variation isn't that critical.
Slick system, though costly and bulky and fragile would be digital readouts like the use on machine tools. You'd need scales on top and bottom and you'd match the readouts. You could do the same thing with stick on measuring tapes but then you'd have to walk around the table in order to see both of them and it wouldn't be nearly as cool.
Also always thought EZ needed to rename the Self Aligning Connectors the Sort of Self Aligning Connectors since they don't self align.
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Old 05-22-2015, 02:21 PM
bumpnstump bumpnstump is offline
 
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Quote:
Originally Posted by sean9c View Post
Totally impractical for the application but I always thought that cable/pulley system they used on drafting tables to keep the arm square when t was moved was slick.
Problem with a rip fence like that on a PBB is that it has to be perfectly parallel as any variation directly shows on your workpiece. Table saw fences only have to be sort of parallel the blade, a little variation isn't that critical.
Slick system, though costly and bulky and fragile would be digital readouts like the use on machine tools. You'd need scales on top and bottom and you'd match the readouts. You could do the same thing with stick on measuring tapes but then you'd have to walk around the table in order to see both of them and it wouldn't be nearly as cool.
Also always thought EZ needed to rename the Self Aligning Connectors the Sort of Self Aligning Connectors since they don't self align.
Before the advent of computers, my artist/graphic-designer wife had a light table w/the pulley system straight edge. Once set up correctly, they stayed set up correctly- a very good/accurate system. I'm guessing one could adapt that system for the EZ-one, but it would need to be semi-permanent, unless it was designed as a drop-in module that could easily be removed. (Actually, that might not be such a bad idea...... hmmm...... ) Plus, there wouldn't be the advantage of quick set-ups for taper cuts.

Re. digital scales: great idea- not sure how I'd make that work. (Doggone it, Sean! now you've put new frontiers in my head for me to explore...... lol... )
I currently use a poor man's version of the digital scales, shown in the pics. Set up is very fast and accurate; is quickly readjusted for varying saw kerf blade changes; repeatability is spot on when resetting to a desired measurement; right hand set-up on one side of the stick/left hand set-up is on the opposite side; this is my go-to measuring stick.
The idea of my single mount fence probably won't offer more than my current set-up, but the concept is intriguing nonetheless. Having gotten w/in 1/32" reliability, I was hoping someone might introduce the 'tweak' I'm missing.
Good input; thanks!!
Rick
ps heh-heh... "Sort of Self Aligning Connectors " ..... good one......
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  #6  
Old 05-22-2015, 03:44 PM
tomp913 tomp913 is offline
 
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Actually, I believe that there is/was a brand of TS fence that used the braided wire/pulley system (the name escapes me at the moment). I used one of these drafting machines many years ago - went from T-square, to the wire/pulley to the articulated arm to the top rail to AutoCAD over the years. Still have a T-square, wire/pulley set-up and articulated arm set-up downstairs (obviously I don't throw anything away - just ask my wife). I was always partial to the wire/pulley as they seemed to stay aligned for a long time - as you say the downside is that they only draw parallel lines.

The IGUS system is pretty fancy, and I'm sure that the parts are priced accordingly, whereas you could probably get into the Miter Slider/Track for less than $40. Re your comment about making the wire/pulley system a "drop-in" unit, the same would apply to the miter slider. You would need a piece of plywood to span between the two SME extrusions, and the fence would have to be long enough to allow for a curved slot at each end over the SME to allow for locking the ends down, whether perpendicular to or angled relative to the SME's.

Tom
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Old 05-22-2015, 05:20 PM
bumpnstump bumpnstump is offline
 
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Quote:
Originally Posted by tomp913 View Post
Actually, I believe that there is/was a brand of TS fence that used the braided wire/pulley system (the name escapes me at the moment). I used one of these drafting machines many years ago - went from T-square, to the wire/pulley to the articulated arm to the top rail to AutoCAD over the years. Still have a T-square, wire/pulley set-up and articulated arm set-up downstairs (obviously I don't throw anything away - just ask my wife). I was always partial to the wire/pulley as they seemed to stay aligned for a long time - as you say the downside is that they only draw parallel lines.

The IGUS system is pretty fancy, and I'm sure that the parts are priced accordingly, whereas you could probably get into the Miter Slider/Track for less than $40. Re your comment about making the wire/pulley system a "drop-in" unit, the same would apply to the miter slider. You would need a piece of plywood to span between the two SME extrusions, and the fence would have to be long enough to allow for a curved slot at each end over the SME to allow for locking the ends down, whether perpendicular to or angled relative to the SME's.

Tom
Yeah..... I think I'll stow this fence away for a while and revisit it another time. I don't want to over-think or over-complicate it. My current fence set-up works very well, and there really isn't a good reason to abandon it. I did use this center-mount fence to cut 11 tapers today- works well. (See pics)
-pic one shows a 'blank' in place, ready for cutting;
-pic two shows the cut;
-pic three shows the pieces of the cut'
-pic four shows all 11 standing together.
Rick
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  #8  
Old 05-23-2015, 12:53 PM
roy_okc roy_okc is offline
 
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Rick,

This is a great idea for a fence.I do have an LS positioner that I intend to someday use as a parallel positioning fence, however, this gives me ideas for an angled cut add-on or separate fence.

I wonder if your situation can't be rectified by reversing the EZ Connector and changing order of tightening. What I'm seeing is that if you first tighten the knob through the center of the fence when it is not parallel, you have so much friction that tightening the other knob doesn't create enough leverage to bring the fence into alignment. However, if you tighten the other knob first, which wouldn't have as much friction, there isn't quite enough leverage to swing everything into good alignment due to not enough EZC on the backside. By reversing the EZC, I'm thinking that you would have enough material to tighten the rear knob first and bring into close alignment without high friction and the fence knob would be able to tweak everthing into perfect alignment.

Another thing to try with the current positioning would be to tighten the fence knob, loosen slightly, tighten the rear knob, loosen slightly, tighten fence, tighten rear.

This might also benefit from some fender washers between the wood and the SME/EZC to prevent the wood from impressing into the SME which would make fine positioning difficult.
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Old 05-23-2015, 01:14 PM
sean9c sean9c is offline
 
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A thing that drives me crazy is having something that doesn't repeat every time. If you're always wondering if your fence clamped square this time or not and having to double check it all the time would be too irritating for me. I'd find that I was measuring both ends of the fence to make sure it's square and if I'm doing that I might as well just measure and clamp both ends.
Unfortunately I have the same problem when using the EZ connectors to connect tracks together and when using the EZ Square. They are so easily bumped out of alignment that I spend too much time double checking.
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Old 05-23-2015, 09:14 PM
bumpnstump bumpnstump is offline
 
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Quote:
Originally Posted by roy_okc View Post
Rick,

This is a great idea for a fence.I do have an LS positioner that I intend to someday use as a parallel positioning fence, however, this gives me ideas for an angled cut add-on or separate fence.

I wonder if your situation can't be rectified by reversing the EZ Connector and changing order of tightening. What I'm seeing is that if you first tighten the knob through the center of the fence when it is not parallel, you have so much friction that tightening the other knob doesn't create enough leverage to bring the fence into alignment. However, if you tighten the other knob first, which wouldn't have as much friction, there isn't quite enough leverage to swing everything into good alignment due to not enough EZC on the backside. By reversing the EZC, I'm thinking that you would have enough material to tighten the rear knob first and bring into close alignment without high friction and the fence knob would be able to tweak everthing into perfect alignment.

Another thing to try with the current positioning would be to tighten the fence knob, loosen slightly, tighten the rear knob, loosen slightly, tighten fence, tighten rear.

This might also benefit from some fender washers between the wood and the SME/EZC to prevent the wood from impressing into the SME which would make fine positioning difficult.
Roy, good suggestions. I went to the shop and tried your suggestions and came up w/the same results: sometimes spot on; other times a smidgeon off. BUT, while doing all of those calisthenics, I noticed I had a bit of wobble where the front, levered knob goes thru the hole in the wood, into the EZ connector, which could easily allow the 1/32" erraticness I'm getting (back levered knob is tight going thru the hole). I'll try bushing the hole and see what happens.
Or, I can just box this thing up and send it to you for an early X-mas project?
Thanks,
Rick
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