gD

28/12/2003 10:19 AM

"Building Up" Tablesaw Top?

Folks,
Need some advice here. First, a disclaimer. I hereby acknowledge
that the best solution is to replace the item in question with a new
(or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
itchy trigger fingers, and save the bandwidth.

On to the problem. I have a Craftsman tablesaw (NO, I cannot
replace it). The top is "dished" towards the center. The lowest spot
seems to be just ahead of the throat--it's about 0.04" lower than the
sides. In his book, "Mastering Woodworking Machines," Mark Duginske
mentions filling low spots with epoxy paint. I've also thought of
filling with some kind of auto-body filler.

So my questions--is this enough of a flaw to be worth correcting
for a properly tuned saw? Otherwise, it's in excellent shape--arbor
runout < 0.002, miter gauges parallel to each other to within 0.001,
blade dead-parallel to miter gauges. On the other hand, how can I get
the blade perpendicular to the top when the top's not flat? And has
anybody done this, and what material would you suggest? I'm thinking
of building a "dike" around the throat and miter slots, then flooding
the top with something that'll self-level, letting it harden, then
gluing sandpaper to a sheet of glass and sanding the top flat.

Comments?


This topic has 17 replies

dd

"dmiale"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 7:02 PM

There is a 2 part epoxy that is used for leveling machinery foundations on
ships. I think it's called Level-All or Level-lite, but I'm sure a Google
search will turn up something.

gD

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 8:06 PM

B a r r y B u r k e J r . <[email protected]> wrote in message news:<[email protected]>...
> How does it cut?

Aside from the fact that I can't figure out where/how to square
the blade or the fence to the surface? Fine.

gD

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 8:09 PM

"Dan Parrell" <[email protected]> wrote in message news:<[email protected]>...
> Question: how did the dip get into the top in the first place ?
> "Dave G" <[email protected]> wrote in message

No clue. Does cast-iron "creep" under steady strain and 90degF
temperature swings? The motor hangs from the front of the top. It was
kept in Dad's unconditioned shed in Northern Virginia until he died,
and then spent at least one winter/summer cycle outside under the
deck.

gD

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 6:39 PM

B a r r y B u r k e J r . <[email protected]> wrote in message news:<[email protected]>...
> >> How does it cut?
> >
> > Aside from the fact that I can't figure out where/how to square
> >the blade or the fence to the surface? Fine.
>
>
> In that case, once you can square it up, use it until you can replace
> it.

That's my problem ... I can't square it up. Where the wood rides
(and hence what blade angle will give a square edge) depends on how
wide the piece is, since the top is curved up away from the blade on
both sides.

gD

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 6:43 PM

"John D. Farr]" <[email protected]> wrote in message news:<[email protected]>...
> Is it a cast metal or stamped sheet metal?

Cast iron.

It's sounding like the recommendations are:

1. JB-Weld, epoxy paint, or something similar, followed by
sanding it down (probably with a full sheet of paper spray-glued to a
flat piece of glass or some such).
2. Call a local machine shop and see what they can do, or
3. Relax my sphincter, and accept that I can't get square edges
... which would be acceptable if I had a decent jointer, but I was
relying on my WWII blade to make up for that ...

Bn

Bridger

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 6:48 PM


>> On to the problem. I have a Craftsman tablesaw (NO, I cannot
>> replace it). The top is "dished" towards the center. The lowest spot
>> seems to be just ahead of the throat--it's about 0.04" lower than the
>> sides.


if this were a metalworking machine the solution would be to hand
scrape the high spots down to flat. might be worth looking into...
Bridger

fh

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 5:12 PM

[email protected] (Dave G) wrote in message news:<[email protected]>...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>
> Comments?



Sounds like overkill to flood the whole top -- you'll probably sand
off 90% of what you put on. Typicl paint film thicknesses are
measured in mil's and your dished-ness is only 40 mil. You'll also
probably want something harder than paint. I wouldn't go with body
filler. And a final note: you might want to sand blast the low spot
to get better adhesion of any material you apply. Blasting can raise
the surface a few thousandths on it's own.

hex
-30-

JD

"John D. Farr]"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 12:51 AM

Is it a cast metal or stamped sheet metal?

--
Bongs not Bombs
Free Tommy Chong
"Dave G" <[email protected]> wrote in message
news:[email protected]...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>
> Comments?

FK

"Frank Ketchum"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 10:27 PM


"Dave G" <[email protected]> wrote in message
news:[email protected]...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>

Well, you didn't mention whether or not the thing cuts good. That's all
that matters. Have you built much with it? Has the problem with the saw
caused any trouble with your projects? If not, I'd say don't waste any time
on it. Don't fix it if it isn't broken.

Of course some will say that all tolerances on any woodworking machine
should be within 0.001 even if the machine is just used to cut 2x4s for an
addition to your house.

Frank

LT

"Lyndell Thompson"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 2:20 AM

This answer will be considered way out by most but here goes, call a local
automotive machine shop and ask them the width capacity of their vertical
mill. If it sounds like it will fit....tell them what you have and get a
price quote on cutting a .004" flycut. If you have a welder you can use a
nickel based rod to build up the hole, and then it can be machined down
(nickel machines easily but will hold up for along time, I have used it on
unreplaceable exhaust manifolds). Of course this means you will have to
remove the table top for the saw...........but depending on machine shop
rates in your area could save you the price of a new saw if a reliable
repair is absolutely necessary. Just my two cents worth. If you decide to go
this route, email me and I will try to dig up the info on the nickel based
rods I used. You can try standard machine shops, but usually the automotive
types are cheaper. Lyndell
"Dave G" <[email protected]> wrote in message
news:[email protected]...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>
> Comments?

EP

"Edwin Pawlowski"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 3:49 AM

>
> In his book, "Mastering Woodworking Machines," Mark Duginske
> > mentions filling low spots with epoxy paint. I've also thought of
> > filling with some kind of auto-body filler.
> >

Just a couple of thoughts.

Will whatever you use hold up being that thin?

How will you machine, sand, or otherwise level it to a closer tolerance than
what you have now?



DP

"Dan Parrell"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 3:29 PM

use liquid metal(JB weld)wash the top first with a cleaner to remove any oil
residue sand lightly and coat with metal,let harden up good for several days
and sand smooth with block.
Question: how did the dip get into the top in the first place ?
"Dave G" <[email protected]> wrote in message
news:[email protected]...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>
> Comments?

Ba

B a r r y B u r k e J r .

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 11:50 AM

On 28 Dec 2003 20:06:05 -0800, [email protected] (Dave
G) wrote:

>B a r r y B u r k e J r . <[email protected]> wrote in message news:<[email protected]>...
>> How does it cut?
>
> Aside from the fact that I can't figure out where/how to square
>the blade or the fence to the surface? Fine.


In that case, once you can square it up, use it until you can replace
it.

Barry

AD

Andy Dingley

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 11:54 AM

On 28 Dec 2003 20:09:16 -0800, [email protected] (Dave
G) wrote:

> No clue. Does cast-iron "creep" under steady strain and 90degF
>temperature swings?

Yes (although it's not strictly creep).

Saw tables are big wide, but thin, castings. Like all castings, they
cool down form the outside first and so they have a stressed skin on
the outside (a bit like tempered glass). Machining _one_ side of this
smooth gives an unbalanced casting that's almost guaranteed to warp.

It also used to be good practice to "season" large iron castings for
six months (or even a year) before machining them. This is no longer
done, for cost reasons. That said, seasoning is no longer as necessary
as it used to be, owing to modern metallurgy being different.

Personally I'd ignore it. If you get that worried, it's time to look
for basically better saws.

--
Klein bottle for rent. Apply within.

sE

[email protected] (EJ_Sawmill)

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

29/12/2003 5:50 AM

I sold a craftsman table saw with a cast iron top having the same
trouble, the fella I sold it to was an auto mechanic who took the
table off and took it to an auto machine shop that had a wide belt
sander for flattening automotive machine heads. Cost him $15 worked
like a charm according to him. I do think he followed that up with
some 600 grit and a nice wax job to complete it.

EJ

Ba

B a r r y B u r k e J r .

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 9:30 PM

On 28 Dec 2003 10:19:30 -0800, [email protected] (Dave
G) wrote:

>
> Comments?


How does it cut?

Barry

Td

"TeamCasa"

in reply to [email protected] (Dave G) on 28/12/2003 10:19 AM

28/12/2003 5:34 PM

Dave, I had the same problem with my old Craftsman. There is no good fix as
the top, in my case continued to dip. However, if it still cuts fine then
just rip then run it through the jointer.

Dave


"Dave G" <[email protected]> wrote in message
news:[email protected]...
> Folks,
> Need some advice here. First, a disclaimer. I hereby acknowledge
> that the best solution is to replace the item in question with a new
> (or used) PM/Jet/Grizzly/Delta/whatever. Not an option. So rest your
> itchy trigger fingers, and save the bandwidth.
>
> On to the problem. I have a Craftsman tablesaw (NO, I cannot
> replace it). The top is "dished" towards the center. The lowest spot
> seems to be just ahead of the throat--it's about 0.04" lower than the
> sides. In his book, "Mastering Woodworking Machines," Mark Duginske
> mentions filling low spots with epoxy paint. I've also thought of
> filling with some kind of auto-body filler.
>
> So my questions--is this enough of a flaw to be worth correcting
> for a properly tuned saw? Otherwise, it's in excellent shape--arbor
> runout < 0.002, miter gauges parallel to each other to within 0.001,
> blade dead-parallel to miter gauges. On the other hand, how can I get
> the blade perpendicular to the top when the top's not flat? And has
> anybody done this, and what material would you suggest? I'm thinking
> of building a "dike" around the throat and miter slots, then flooding
> the top with something that'll self-level, letting it harden, then
> gluing sandpaper to a sheet of glass and sanding the top flat.
>
> Comments?


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