Benefits of a parallel slide router table fence ?

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Forum topic by DrGang posted 08-23-2012 01:17 PM 6680 views 0 times favorited 28 replies Add to Favorites Watch
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14 posts in 2128 days

08-23-2012 01:17 PM

Topic tags/keywords: router table fence parallel slide

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 ?

28 replies so far

View Gene Howe's profile

Gene Howe

10535 posts in 3454 days

#1 posted 08-23-2012 02:13 PM

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.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View Bill White's profile

Bill White

4948 posts in 3986 days

#2 posted 08-23-2012 02:21 PM

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.


View DrGang's profile


14 posts in 2128 days

#3 posted 08-23-2012 02:58 PM

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.

View Loren's profile


10476 posts in 3673 days

#4 posted 08-23-2012 04:15 PM

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

View DrGang's profile


14 posts in 2128 days

#5 posted 08-23-2012 04:37 PM

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.

View jmos's profile (online now)


839 posts in 2395 days

#6 posted 08-23-2012 04:51 PM

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.

-- John

View DrGang's profile


14 posts in 2128 days

#7 posted 08-23-2012 05:00 PM

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 ! :)

View PurpLev's profile


8536 posts in 3674 days

#8 posted 08-23-2012 05:09 PM

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.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Gene Howe's profile

Gene Howe

10535 posts in 3454 days

#9 posted 08-23-2012 07:48 PM

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.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View DrGang's profile


14 posts in 2128 days

#10 posted 08-23-2012 10:01 PM

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 ?

View Dan Lyke's profile

Dan Lyke

1520 posts in 4150 days

#11 posted 08-23-2012 10:42 PM

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.

-- Dan Lyke, Petaluma California,

View DrGang's profile


14 posts in 2128 days

#12 posted 08-24-2012 12:10 AM

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 !

View NiteWalker's profile


2737 posts in 2602 days

#13 posted 08-24-2012 12:37 AM

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.

-- He who dies with the most tools... dies with the emptiest wallet.

View OggieOglethorpe's profile


1276 posts in 2136 days

#14 posted 08-24-2012 01:09 AM

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.

View oldnovice's profile


6898 posts in 3393 days

#15 posted 08-24-2012 01:20 AM

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

-- "I never met a board I didn't like!"

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