This document covers my repair-rebuild of a Rockwell tablesaw, model 34-348. This model was the precursor to the current delta 34-444 and I'd imagine most of the items discussed are relevant to similar contractor-style saws.
I acquired an old 10" Rockwell Contractors Saw and wished to make it "run and look like new". The mobile base was in good shape, as were the wheel cranks. However the cast iron tabletop and all steel items were badly rusted (although structurally sound) and the arbor had about 1/8"+ play side-to-side.
Saw was basically useless as is, but the price was right.
It should also be noted the more I take apart and "make like new" the more I take apart the "marginal" stuff, then the stuff that looked good to begin with starts to look bad ... you get the picture.
Obtaining The Paperwork And Creation Date
Called Delta at 1-800-223-7278 and gave them the model and serial numbers. Literally within 30 seconds I was told the saw was made in 1975 and that a parts list and user manual would be sent immediately, no charge. Received the paperwork five days later. Nice way of doing business. I also called and spoke with technicians twice they answered each of my questions accurately and with no hesitation. I'll buy Delta again.
Other than rusty bolts, this was painless. Four bolts hold the cast iron top to the base, four more bolts hold the trunnion assembly (trunnions,
cast housing for arbor/bearings, worm gears, motor mount plate, etc.) to
the cast iron top. Knock two pins from the crankwheel shafts and the cast
iron top and trunnion assembly come right off. Be aware that the only
thing holding the female section of the trunnions to the male section of
the trunnions is grease -- that is, both trunnions can slide off if the
(lack of) grease permits.
Arbor and Bearings
"See through" diagram showing bearings and
stops in housing and where bearing A and B are positioned:
My arbor was badly worn and wiggled side-to-side quite a bit, seemed like
the bearing on the pulley side was "shot". This would never allow a straight cut of any kind on this saw.
A Little Background:
The arbor/bearing assembly depends on "press fits" on both surfaces of the bearing, that is the outside of the bearing itself (the OD) is press fit into a cast housing, and the arbor is press fit on the inside (the ID) of the bearing.
Inherently there are problems with this design, the first of which is that
care must be taken not to "crush" the bearing during assembly. If both press fits are "tight" you will crush the bearing so that it is difficult or impossible to turn.
The second problem will show up over time in just about every such
application requiring press fits on both bearing surfaces. The problem
is that one press fit will loosen over time more than the other -- this
begins a cycle whereby the one "looser" fit begins to "walk" on the mating surface. When this happens on the ID of the bearing, the bearing itself can literally "eat" right through the arbor (called fretting corrosion) and actually cut it in half! I doubt this is a real concern in a tablesaw as drastically poor performance would show up long before the arbor gave way (which describes my case).
Before you begin disassembly of the arbor and bearings, itís a good idea
to take the following measurements (refer to diagrams):
- Length of arbor from the end (pulley side) to a point on the cast
- Distance from any point on the pulley to a point on the cast housing;
- Distance from any point on the flange to a point on the cast housing.
Also, check to see if the small part of the flange butts up against the ID of the bearing. This may depend on whether changing blades on your saw requires a spanner wrench to be inserted on the non-blade side of the flange -- the flange may have flats. If you need to fit a spanner wrench in there, make a measurement.
NOTE: My flange was a "universal" flange used by Rockwell which has flats on the bearing side of the flange. However my saw does not make use of these flats, therefore the flange is pushed flush to the ID of the bearing, which means the flats are then inaccessible. Your saw may or may not need access to these flats.
These measurements will need to be duplicated during re-assembly UNLESS
(as in my case) the whole assembly is so worn/shot that these measurements
are probably not reliable to begin with. If youíre simply changing
bearings due to mild problems and there is no obvious sign of axial arbor
movement on the bearings*, take these measurements. Chances are oh, astronomically small that your owners manual or parts list has these
One way to check is if your saw has a mounting bracket or plate for a splitter, check to see if the flange on your arbor lines up with the mounting plate for the splitter (although this mounting plate should be adjustable within a small range). Remember (when installed) the splitter should end up in-line with the blade, so you may have to visualize a blade and splitter in place, particularly if your splitter mounting location is offset from the splitter itself. Mine was in-line with the blade, therefore the mounting bracket should be in-line with the arbor flange (this would also be a sign of arbor movement -- if your splitter no longer lines up with your blade).
Check your assembly for any locking or retaining nuts on the bearings.
On the flange side chances are you wonít be able to see that side of the
bearing, but chances are better than great that there is no retaining nut
on that side (impossible to install and the flange acts as a retainer in
my case). So, after removing the pulley look for retaining nuts on the
pulley side and remove. My particular saw was missing a retaining ring
for the OD of one of the bearings ($9.45 replacement cost from Delta,
which is a lot for a $.50 nut but at least they keep 'em in stock).
Assembly and disassembly of a pressed bearing requires slow, consistent
application of force. Translation? Use an arbor press to remove or
assemble arbors and bearings. If you do not care to save the current
set of bearings, you can disassemble by gently tapping the non-flanged
end of the arbor with a hammer, but youíll have to (80% of the time)
scrap the bearings. Impact forces are generally destructive to bearings.
Donít worry too much about ill affects on the arbor, it will come out
unscathed. Please note that depending on how far youíve "broken down" your assembly, staging the cast housing to allow access to pressing the arbor or bearings using the arbor press is somewhat tricky. It will require a few different types of rams and two or three pairs of hands
If you do not have access to an arbor press you simply will not be able
to re-install reliably. If your saw is relatively new and you think
you may be replacing bearings 10 years from now, Iíd suggest checking
the paper for used arbor presses and scoop one up. Otherwise, call
around to machine shops, repair shops, etc. in your area or give your
local Delta (or other) dealer a call -- they may know someone or may
perform this as a service.
After disassembly it was apparent one bearing was less than optimal.
The major problem however was that the arbor had worn down over 1/8"
per side under the suspect bearing, so that it was literally spinning
"free" on the pulley side. Although both bearings were "OK", I decided to replace them.
Since I deal with bearing distributors I was able to fax my bearing specs
and identifiers (markings on the bearing seals) to a few places for quote.
I selected 17mm ID x 40mm OD x 12mm WD, 2 seals, standard lube, ABEC-3
bearings, NSK model number 6203VVC3. You should strive to get ABEC-3 bearings, although ABEC-1 rated bearings would probably do (higher ABEC rating = closer tolerances). Higher than ABEC-3 is probably overkill for a tablesaw, and very expensive (i.e., ABEC-7's may cost close to $100 ea).
I decided to add weld beads to my arbor and grind it down to itís original
diameter (figure 2, section B). I also had to make a wider retaining nut
since a threaded section of the arbor was worn away (figure 2, section y
has threads for a retaining nut). If you canít do this yourself or find
someone to do it cheaply, youíll probably have to purchase a new arbor.
Section A (figure 2) is where bearing A is pressed. This surface
is ground to a tight tolerance. NOTE: Your saw may have a space between section A and the flange;
Section B (figure 2) is where bearing B is pressed. This surface is
ground to a tight tolerance;
Sections x and y (figure 2) are non-ground surfaces and will have smaller
OD's than sections A and B, thus they should float freely under the
bearings. Some saws will have a spacer or spring in section x;
Section z (figure 2) is where the pulley is mounted;
As mentioned earlier, staging your assembly is the trickiest part here.
In my cast housing for the bearings (and I imagine in most), a stop was
built in so that the bearings are pressed in from one side (the outside)
and down to the stop (see figure 3). Assuming you can stage OK, the
sequence for re-assembly that I found worked best is:
- Press* a bearing (A) into the cast housing on the flange side.
Press it all the way down to the stop.
- Press the arbor through the first bearing (from the outside), starting with the pulley end of the arbor. In other words from figure 2 above, section y and then section B pass through the bearing A. The arbor section x should now float freely under bearing A. I did this step after step one only because the housing is already staged in this direction.
- Step #2 can be done before #3 if you wish, however do not press the arbor all the way through to section A yet (which is itís final destination).
- Now flip the housing over and press* bearing B into the cast housing (down to the stop). If your saw has a spacer or spring for section x, put it on prior to this press.
- Now flip the housing back over and press* the arbor down through bearings A and B simultaneously. Make sure bearing B is supported and does not move away from the housing stop. Press the arbor until you hit the measurements taken above prior to disassembly. If your flange originally butted up against the ID of bearing A, press to this point.
- Make sure the arbor spins freely and there is no play. Re-install retaining nuts.
- Re-install the pulley to the original measurements. The arbor keyway was dinged on my saw which did not allow the new machined pulley to slide on. A few strokes with a metal file took off the burrs.
When pressing, go about 1/4" at a time and then stop and check to make sure the bearing still spins freely. If it does not, if the "feel" has degraded at all, the press fit is too tight or the bearing is misaligned. If the press is too tight, you may have to take the bearing out and rub emory cloth on the mating surface to take off a fractional amount of material. If it's misaligned, press the bearing out and try again.
Cast iron Table Top
My top was badly rusted and was at some point used as a stand for painting and/or paint supplies. I tried oven cleaner and Naval Jelly, which worked OK but would have taken (literally) 3-4 hours to use. After much contemplating, I decided to sandblast the cast top. I started on a small section and much to my surprise it worked extremely well. After 5-10 minutes of sandblasting it came out looking like new. Checked for flatness (fine) and coated it with lubricant IMMEDIATELY after wiping off excess sand.
Rip Fence and Guide Bars, etc.
The rip fence, rip fence guide bars, and throat plate were all rusted. Sandblasted to bare metal and repainted.
Machined Pulleys and Link Belt
The saw had the original cast pulleys and original(!) belt. Not much of a decision here. I purchased the machined pulley/link-style belt kit for Delta saws from the Woodworkers Store. This was kinda neat they put Tech Support on the phone for a three-way conversation between myself, the order taker and Tech Support. They asked for current pulley sizes and the Tech person had the order taker send the order to him, he would fill it personally with the correct kit (there are two available).
The machined pulleys did not fit on the arbor due to a burr on the ID of the machined pulleys where the set screw through-hole meets the ID. Quick deburr with a file made all fit fine.
The Rockwell comes with a lightweight toggle switch for on/off operations with a junction box mounted inside the saw. My switch was stuck in the "on" position and needed replacement (the power cord was also frayed and taped up). I purchased a two button box and new power cord from McMaster Carr. I mounted the two button box on the outside of the cabinet.
I would recommend reading any or all of the following:
Shop Notes, Vol 5 Issue 25, January 1996
Fine Wood Working, October 1995, #114
Woodworker's Journal, Vol 20, #2, March/April 1996
They each contain articles on the components of tablesaws, what lubrication to use where and how to re-align everything once you get it put back together (the FWW article is a little more detailed, but they each have their strengths). I use tips from each article and cannot add a whole heck of a lot more than what these three articles provide.
The saw was put back together, aligned and then sold to a lucky new owner. Had to make room for the incoming used Robland X31, which is an entirely different story, detailed in yet another file.