Clone of a Biesemeyer Table Saw Fence

Building a Clone of a Biesemeyer Table Saw Fence

© John A. Swensen 1996, 2006. All rights reserved.

The stock rip fences that come with many table saws leave much to be desired, and there is a booming business in improved, after-market fences. One of the

more popular fences is the Biesemeyer T-square® saw fence system, which provides an rugged, accurate, and reliable fence constructed from standard

structural steel shapes, rather than from custom aluminum castings and extrusions. The simplicity of construction and the cost of over $300 for thecommercial version of the fence convinced me to try to make my own.

This article describes a fence I built for my table saw. It resembles, and was based upon the Biesemeyer T-square® fence, and is thoroughly rigid and

accurate to 1/64" using a vernier cursor. The fence angle can be easily adjusted parallel to the blade or to provide slight clearance past the blade. The fencehas tapped holes to simplify mounting of auxiliary fences, and is sufficiently high to provide a place for push sticks and to hook extra fingers during narrow

rips.

I built this fence about thirteen years ago, and I continued to refine it for a few years after that. Since then, Beisemeyer was bought by Delta, and I replacedthe saw and fence with something I like better.

About four years ago I gave away my table saw and fence after I found an Inca model 250 tilting-table saw for a reasonable price. Since the table height-

adjusting mechanism was broken and replacements were unavailable, I made a new mechanism out of solid aluminum, straightened a few bent castings, and Ihave been enjoying the exquisite precision of this Swiss beauty ever since.

The Inca has a completely different fence than the one descibed on this page; is lightweight, easily knocked off square, and has no builtin measuring scale but,

when used with care, it can be very accurate. I sometimes miss the ruggedness and ease of setting rip widths that I enjoyed with my shop-built fence, but Ihave never missed the vibration, wandering settings, and general crappy construction of my old imported contractors saw.

Please note that I took no photographs of my old fence, nor did I make drawings, and my memory of it is beginning to fade, so this slightly-edited description

is about all that I can provide for those who may want to try to build one, themselves. Those wanting more concrete illustrations are encouraged to examinethe advertising literature from Delta, Jet, and other machine manufacturers.

Be warned that this project is a lot of work, and it is not all that cheap. Welding is probably required for the T-square joint, and the builder will likely

experience a few burns and ragged, oily wounds in the process. Drilling and sawing thick steel requires cooling fluids, and drilling 3/8" and 1/2" holes in thick

steel kills little drills. (To repair such drills see Fixing Makita Drills).

Description

I have tried to use consistent colors to show different parts of the saw and fence; the original saw table is sage green, the added extension table is forest green,

the fence support angles are rust colored, the front rail is purple, the fence, itself is light blue, and the fence T-square is dark blue. The fence clamp is red,fasteners (usually 1/4-20 machine screws) are grey, and glide bearings are coral colored.

A front angle supports the front rail and extension table. On the front of the saw is mounted a 3"x3"x.250" steel angle, with the corner down. Attachment uses

1/4-20 bolts on 10" centers, with holes drilled and tapped into the saw table top (alternatively, you could use any existing holes in the top). The top edge ofthe angle is flush with the top of the saw table, with cut-outs for the miter-slots.

Building a Clone of a Biesemeyer Table Saw Fence http://home.comcast.net/~jaswensen/machines/fence/fence.html

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A similar angle is mounted on the rear of the saw to support the fence and extension table. Besides the cut-outs for the miter-slots, contractor-type saws with

motors that hang out the back of the saw require a notch to clear the motor mount during bevel cuts. The 3"x3"x.250" angle is overkill for the rear, and a

2"x.125" flat bar would probably do. However, the angle is nice for mounting legs, out-feed tables, etc.

Legs bolted to the ends of angles are required to keep the saw upright. Most commercial legs are made from 1-2" square tubing welded to a piece of angle.Although I didn't build these kinds of legs, I wish I had.

A 2"x3"x.125" rectangular-section front rail rests horizontally on the front angle with a gap large enough for the fence cross angle to clear. The rail supports

the fence cross angle, and has a Starrett stick-on measuring tape for the gauge. The rail extends past the front angle on the left and right ends to support thefence cross angle through the full range of fence positions. The front rail is attached to the front angle using 1/4-20 bolts from the bottom of front angle on 10"

centers, into Thread-serts (made by Creative Engineering). The .125" rail thickness is needed to resist crushing from fence clamp. The front rail must be

perpendicular to the miter slots, uniformly distant from the edge of the saw table top, and parallel to the top in the horizontal direction; shim and/or enlargebolt-holes to adjust.

The T-square fence consists of a fence bar on top of the table and a cross angle that sits above the front rail. The rectangular fence bar is 2"x3"x.080", longenough to hang 4" in front of the table edge, and even with the back angle (to allow a hold-down clamp in back, if desired). The fence-bar lays on its longer

side, and is faced on either side with 1/2" Finnish or Baltic birch covered with Formica on both sides. Fence height is 3.5", which allows for clamping on jigs,

junk between faces, etc. Fence sides have 1/4" holes backed by 1/4-20 Thread-serts in the bar on 4" centers. Every other hole is counter-sunk for flat-headattachment screws, leaving the extra holes for mounting auxiliary fences, jigs, etc. Brass shims are used between the Formica-plywood faces and the fence bar

to get them straight and vertical. Exposed edges of the brass shims are cut off to avoid slicing fingers.

The fence cross angle is 2"x3"x.250", long leg horizontal, short leg dropping down between front angle and front rail. A 23" length is adequately rigid.Although I welded my fence bar to the cross angle, very-accurately drilled holes and bolts might be rigid enough. (A first attempt, using 4: 1/4-20 bolts in

oversized holes failed because I could not tighten the bolts enough to prevent slipping during use.) The ends of the short leg are drilled and tapped for 1/4-20

short bolts with the heads on the front-rail side, and with jam nuts on the front angle side. The heads of the bolts need to be ground flat and a little thinner, asthey are used to adjust fence squareness. Note that only slight adjustments are possible. These bolt heads are covered with flat springs made of 4.5" lengths of

old hack-saw blades, mounted at the inboard ends using two 8-32 or 10-24 screws each. (To drill hacksaw blades see spot annealing. The ends of the springs

over the bolt heads are covered with little pieces of Formica glued on with epoxy, to act as low-friction glides. The springs and glides also help keep the boltheads from turning when sliding the fence.

The ends of the long leg of the cross-angle are drilled and tapped for 1/4-20 nylon screws, mounted upside down, to keep cross angle level (these are not

essential with the wide fence bar and a flat table and extension table).


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On the right half of the cross angle a 3/4" by 2" cut-out allows the cursor to be mounted underneath. Two 1/4-20 Allen-socket set-screws have jam-nuts

silver-soldered to the ends opposite the sockets. These are screwed from the under side into tapped holes about 1" beyond the edges of the cutout, and clampthe cursor in position and allow zeroing the cursor. The Allen sockets allow adjustment of the cursor from above. The cursor is 1/8" acrylic, glued to some

1/16" slotted aluminum straps on either end. Epoxy will hold if you don't put much force on the bond. By bending the aluminum straps, the cursor can be

made to hang just above the stick-on measuring tape, reducing parallax error. (If you like magnifying cursors, a piece of 1/2", half-round acrylic rod, with theflat side down and the long axis parallel to the fence bar, can be substituted for the flat acrylic.) The hairline is made by cutting the smallest possible scratch

with a sharp knife on the underside of the acrylic, running a permanent marker over the scratch, and cleaning the surface with alcohol afterwards, leaving just

the scratch colored. A vernier is made by using a precision rule to mark additional hairlines at 5/64", 5/32", and 15/64" from the main cursor line. Make thesea different color than the main hairline to avoid confusion.

Fence clamping uses a Destaco toggle clamp mounted on a piece of angle welded between cross angle and fence bar, hanging down to make a local U

covering the front rail. A piece of brass is bolted between the front rail and hanging angle, and hangs down to the pressure point on front rail. This isolates theshearing forces from the clamping force produced by a bolt through the slot in the toggle clamp. The fence has 3-points of contact with front rail: the two ends

of cross angle behind front rail and the bolt on the toggle clamp. Clamping pressure is adjusted by screwing the clamping bolt in or out. It is important to mask

out any paint on the front and back of the front rail at the lines of contact to avoid chipping and wearing off paint and affecting accuracy.

Sizing

Any fence length can be built, but don't forget to add half the sum of the widths of the fence bar and cross-angle to the desired maximum rip widths. For

example, my fence bar is 4.5" wide and my cross-angle is 23.5" wide, so for a 50" right and 12" left rip capacity, my front rail must be 50 + 14 + 12 + 14 =90" long.

As the stiffness of beams is proportional to the cube of the depth, and as the accuracy and stiffness of the T-square is linear with the width, be careful about

reducing the width of the fence bar, front rail, or cross angle. It is essential that the cross-angle rests below the table top, so be careful about using too shallowa front angle.

Materials

Thick metal is required for the clamping surfaces; the original .080" front rail dented from repeated clamping. I found a steel supplier locally that caters tohome builders and, although they charged a premium prices, their prices were lower and selection was much better than at the local home center or hardware

store.

Additional Construction Notes

I used oversized bolt-holes and bolts to allow room for adjustment. In view of some of my errors, this was prudent, but a neater job would use counter-sunk,

flat-head screws in accurately-drilled holes. The cast-iron table drilled and tapped nicely, although cutting, drilling and tapping the 1/4" steel was miserable. If

you mount the front and rear angles first, you can easily clamp the front rail and fence pieces in place to check clearances, etc. You will want to build and fiteverything together, then disassemble and paint. Zynolite Epoxy Rust Mate paint worked very well, and scotch tape did a fairly decent job of masking off the

clamping lines on the front rail (it was hard to get off, though). Wax has prevented rust in these unpainted areas. If you paint the top of the front angle and the

underside of the front rail, a piece of Mylar packing tape between them will allow adjusting the angle and spacing without the paint sticking (permanently) toitself.

Areas for Improvement

The fence is heavy and bulky, especially with its 48" rip capacity, but that seems to be a property of most long fences. Some weight could be saved byreducing the thickness and size of the front and rear angles, or by using channels or I-beams, as noted below.

There is no micro-adjustment feature, although the vernier cursor and judicious bumps work almost as well.

The exposed bolt heads attaching the front angle catch on my knuckles when I wipe out the chips in front slot. Flat-head screws in accurately-drilledholes would eliminate this problem. This sawdust-catching slot is also a minor pain, too.

I used torsion-boxes for the extension table (and router table), bolted to front and rear angles with threaded inserts. With the clamping force limited by

the inserts pulling out, the torsion-boxes shift from time to time. I would prefer resting a table board on additional angles mounted on insides of front


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and rear main angles.

The front angle and front rail are redundant, and could be replaced with a channel, with another piece of channel acting as the fence cross piece.Clamping to the solid channel face would eliminate the crushing problem, as well. This variation would require that the scale and vernier be located on

the front face of the channel, which would have the advantage of keeping them free of sawdust, although it might require stooping to read.

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Building a Table Saw Fence / [email protected] / revised 2006 December 27


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Clone of a Biesemeyer Table Saw Fence