# Benefits of a parallel slide router table fence ?



## DrGang (Aug 23, 2012)

Hi all,

This is my first post on this forum and I'll start by asking people's opinion about an optional feature of router table fences : the ability to slide along a rail/channel. 
I'm making a new fence for my router table and find myself at a crossroad. I can go down the easy path and just use F-Clamps or T-bolts to secure the fence. Or, I can pick the uphill, rocky path and buy or design a parallel sliding mechanism. There is a number of options to achieve that and I think I can deal with such a project but my question is : *Is it worth the trouble ?*

I'm expecting the positioning the fence will be easier than using the Trend height/depth gauge, provided that the sliding mechanism is robust is reliable but precisely, will it be ? Do you guys trust what you read on the rule or do you end up double checking with a gauge or something ?

Right now, I'm in the mood of not bothering with a parallel sliding fence because I can't believe the fence will remain perpendicular all the way, rendering pointless the whole jig.

What do you say ?


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## Gene01 (Jan 5, 2009)

I use two fences. One is a manufactured one that stays parallel and, one is shop made and does not stay parallel. As you surmise, since the bit travels in a circular path perpendicular to the table, a parallel fence is of no consequence.


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## BillWhite (Jul 23, 2007)

I built sliding fence "faces" into my router table fence. Just routed a "T" slot in the sliders. 2 bolts for each side. I've had no probs wih it at all. Faces are mdf-shellaced and waxed.
Bill


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## DrGang (Aug 23, 2012)

To Gene :

Are you saying that fences not made of metal are going to give ? Or is it because the precision attainable by a DIY-er is not sufficient to guarantee the fence will keep the same angle when adjusted ? Or both ? 
There are fairly affordable systems out there like the Kreg table saw fence which can be adapted for a router table. If commercial products are significantly better than anything homemade, I'll have to reconsider my options because the minimum spending will be 100£.

To Bill :

There is probably a misunderstanding here. I'm not talking about the fence "faces" sliding to reveal more or less of the bit but the whole fence sliding along a rail while keeping its angle to the table's edges. I have built sliding "faces" on my fence but with a through-channel rather than a T-slot.


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## Loren (May 30, 2008)

I just clamp the fence to the table. Then you can move the fence
1/8" at one end while the other end stays clamped at the distance
at the bit changes by exactly 1/16". Most router table cuts are
edging cuts and most fence adjustments are small ones.

There's not much benefit to having a parallel fence imo, 
unless you are (a) using it as a stop in tandem with a miter
gauge in a miter slot (which you don't need either in a router
table) or (b) need parallelism because you are using a power
feeder.


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## DrGang (Aug 23, 2012)

Well, I'd argue about that exactly 1/16'' based on geometrical considerations. It depends on where the clamp is and where the 1/8'' is measured. You basically need to make sure the distance between the pivot point and the router bit centre is the same as the distance from the router bit centre to the point of measurement.

It's hard not to fall for that "arm race" when you're building a new piece of equipment I must say. There is always this nagging feeling in the back of your mind that you might need this fancy feature one day. You also know that building-in the feature is more exciting than having to upgrade a piece of equipment you got used to over time.

It's so difficult to get that balance right between what is optional but is better built-in than added-on.


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## jmos (Nov 30, 2011)

I've never had any real need for a parallel fence. If you were planning on using sled with a miter bar, I suppose it would be required (although I don't know why you would do that), or, as Loren mentioned, a power feeder, but for most operations it doesn't matter if the fence is parallel. Just make it easy to tighten and loosen and you should be in good shape.


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## DrGang (Aug 23, 2012)

Ok well, if there are no good reasons to bother about building or buying a parallel sliding system, good. I'll save money and time !


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## PurpLev (May 30, 2008)

If you are doing a lot of grooving/dovetailing/joint work on your RT than a system like the Incra positioner (example for a parallel fence system) really saves time and effort as the readings on the scales are precise and you do not need to check bit distance before every cut (something that for mid part cuts is not as easy as using a depth gauge as the bit can be 12"+ away from the fence). if on the other hand you are doing mainly (if not just) edge work than the benefit of such a system are almost non existent.


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## Gene01 (Jan 5, 2009)

DrGang,
I'm sorry I wasn't more plain. 
A one piece fence, no matter it's orientation relative to the table, will allow the same cut. A two piece fence is another story. The manufactured one I mentioned is a two piece fence and either side can be adjusted in or out. 
Even a one piece fence can be used as a jointer by adding a piece of laminate on the out feed and adjusting the fence to cutter to take just that much off.


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## DrGang (Aug 23, 2012)

Hey Gene, there was indeed a misunderstanding.

I've heard of, and used the trick of a fence for jointing when a small shift is introduced between the infeed and outfeed faces. I don't think I've ever come across a two-part fence, let alone a homemade one. Most fences have a common table-wide base to which (occasionally movable) faces are perpendicularly attached.

At this stage and with the replies I've had, my feeling is that there is very little use for a router table fence that can be adjusted while remaining parallel to the table front edge. I'll go by jmos' advice and focus on getting the fastening mechanism right. Real challenge here, let me think for a second … mmmmh how about t-tracks, t-bolts and knobs ? How original is that ?


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## DanLyke (Feb 8, 2007)

The only reason I can think of to care whether the fence slides parallel to the table is if you've got some sort of screw or indexed adjustment that gives you a very accurate fence-relative ability to change the fence position. I say "fence-relative" because normally what I'd do is put a spacer in between my bit and my fence.

I'm currently building (as in the white oak is planed, waiting shop time for cutting and assembly) a fence for my new router table. It will have screw-type end clamps that go over the edge of the table. My plan is, at some point, to route a slot behind the bit on the table and make an attachment for the fence that rides in that slot and lets me adjust the position of the fence. I'll still have to unclamp the ends, I want a fence that stays really solidly where I set it, but I'll be able to unclamp the ends and either thread-adjust the position, or step it in precise 1/16" increments.

So maybe just planning on a hybrid like that? It's not like you need indexed moves for everything, just for things like nested dovetails that are too complex for a dovetail jig, so something you can take on and off that gives you the precision relative movements when you need it, but lets you just slide the fence when you don't, seems like a reasonable compromise.


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## DrGang (Aug 23, 2012)

Yeah precisely, that was my point in my first post : ease and precision of positioning, I did not expect any other benefit from such a fence. That said, if the precision I can achieve when I build my fence is inferior or comparable to a reading from a depth gauge, I may as well not bother. 
The more I think about it, the less I feel like spending 100£ on the Kreg table saw fence !


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## NiteWalker (May 7, 2011)

I use a pivoting fence and have for years.
IMHO parallel fences bring nothing to a router table.

For precise measurements, I use workpieces and set-up bars as much as possible to avoid measuring.


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## OggieOglethorpe (Aug 15, 2012)

What he ^^^^ said…

I do sliding dovetails, dados, etc… without a parallel fence. MDF is really cheap, and very reliable for fine tuning a test cut.

Remember, outside of factory production, there is very rarely a need for one-thousandth repeatability in woodworking. Simply learn to think from a reference point and run matching parts with the same setup.

For example… you're building a gallery of cubbies for a desk, or the internal dividers for a spice box. Cut the top and bottom with the same setup, and every divider will be square and accurately spaced.

The best way to accurately measure is not to measure at all… It's relative vs. absolute woodworking.


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## oldnovice (Mar 7, 2009)

My Benchdog RT came with a single piece extruded aluminum fence with two MDF faces that can be moved to open and close on the bit. Additionally two spcaers were supplied to move the out feed MDF outward so that the router can be used as a jointer (skeptical at first, but it does work)!

Bench dog fence


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## KnickKnack (Aug 20, 2008)

I have both fences - a pivoting one, and a home-made micro-adjustable one.
I'd make 2 comments…

The pivoting one is nice and easy to use and set up, and, yes, you can "niggle" off a bit more just by moving one end a bit. The one thing to take note of here though, is that if you're using *stop blocks* attached to the fence then things can, and do, get a bit weird. If the stop block is set to stop your cut, say, 2" from the end of the piece, then as you rotate the fence away from the bit that 2" becomes steadily more and more.
IMHO parallel fences bring nothing to a router table
I'd have to disagree strongly with that *if* your fence is accurately adjustable. I can route a 12mm dado, for example, using a 10mm bit simply by cutting a single slot and then moving the fence over by exactly 2mm and making another pass. You can use it to produce accurate box/finger joints, etc etc - the ability to do a cut "another half a mill" over is, I find, invaluable.
Should you be interested in the micro-adjustable design, I wrote some stuff about how I made it here (the guts are in part 2).


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## DrGang (Aug 23, 2012)

I was surprised until this morning at the poor turn-out of parallel fence supporters. This is now sorted.

Regarding positioning, it's hard to beat a proper micro-adjustment system by hand.
However for a practical setting and reading of the fence position, I just thought about that : One could apply two strips of adhesive ruler on the router mounting plate so that the zeros are aligned with the bit centre. If the fence faces are really parallel and aligned, a reading can be made directly from there. 
A very shallow dado cut needs to be made in the plate for the strips to sit flush though. This may be tricky.


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## b2rtch (Jan 20, 2010)

" Additionally two spcaers were supplied to move the out feed MDF outward so that the router can be used as a jointer (skeptical at first, but it does work)!' 
That remind me that I have no idea where I put these spacers.


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## DanLyke (Feb 8, 2007)

Bert, you space out the outfeed side of your split fence, so that when you run past the bit the second part of the board is resting on fence, and not hanging out in the wind (which would cause jointer snipe at the tail).


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## b2rtch (Jan 20, 2010)

Dan, I understand that I just do not remember where I put the spacers.


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## b2rtch (Jan 20, 2010)

http://www.benchdog.com/profence.cfm

I look at this picture on the webpage advertizing all the benefits of the Bench Dog fence, and I wonder what could be the advantage of using the feather boards upside down!!!!!

Any idea?
May be if the table flip over.


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## KnickKnack (Aug 20, 2008)

I look at this picture on the webpage advertizing all the benefits of the Bench Dog fence, and I wonder what could be the advantage of using the feather boards upside down

I believe it's being used as a stop block in this picture.


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## b2rtch (Jan 20, 2010)

What about the one on the right side?


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## DrGang (Aug 23, 2012)

I guess the right one is there so that you don't lose it, like the spacers…


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## ssnvet (Jan 10, 2012)

*so that you don't lose it, like the spacers*

touche'!

I confess I never really got the paralell fence thing… though I guess it could be a convenience, the cost seems excessive.

I think the ideal application would be routing fluted columns with a bullnose bit.

I made a Federal style pediment with columns and plinth blocks for my front door… routing the fluted collumns out of 8/4 clear pine stock, using a 3/4" bull nose bit and managed to get perfectly spaced geometry by measuring carefully and making test cuts in scrap.

I think the parallel fence would have saved me some time, but in my situation would have hardly justified the expense.


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## Viktor (Jan 15, 2009)

"There's not much benefit to having a parallel fence imo, 
unless you are (a) using it as a stop in tandem with a miter
gauge in a miter slot (which you don't need either in a router
table) or (b) need parallelism because you are using a power
feeder."

- In addition to what Loren mentioned c) your router can tilt (a feature that only shapers usually have).


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## oldnovice (Mar 7, 2009)

I saw a photo on LJ where the TS rip fence was connected to the RT fence to keep it parallel. Of course the TS fence must also stay true (not like mine) in order to work properly.

I have system I use that works but I don't have any pictures to show how it works so I will attempt to describe it.

Essentially it was a home made tenoning jig that fits into the miter slots on my TS. For the RT I turn the jig away from the saw blade and towards the RT fence with the jig in contact with the RT fence. My jig has a magnefied rule scale with it's zero set at the center of the router. So if I set the jig to zero and adjust the RT fence in contact with it the RT fence is dead center on the router center. Sine the jig has a wide face that makes contact with the RT fence I get very good parallelism.

The description is not as good as a photo so if anyone wants a photo please let me know and I will post it here!


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## pintodeluxe (Sep 12, 2010)

You will never need a parallel fence unless using a miter gauge on the router table. 
I just use a square of MDF to hold end-grain cuts perpendicular to the fence (or a sled with hold-downs).


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