LumberJocks

Revamping my Delta Contractor Saw #9: Taking Back What I Said, and An Experiment

  • Advertise with us
Blog entry by Mark Colan posted 09-01-2010 01:39 AM 2045 reads 0 times favorited 7 comments Add to Favorites Watch
« Part 8: Problem Solved! Phase I Complete: Success! Part 9 of Revamping my Delta Contractor Saw series Part 10: The Core of the New Extension Table »

Taking Back What I Said

Mark Mueller disagrees with my statement (in Part 8, Conclusions for Phase I) that “re-zeroing the fence will be required any time the positioner base unit is moved.” He points out that the fixed stops (against which the base is positioned) make re-zeroing unnecessary, and he may well be right (he should know). I will revisit this subject later, after doing some experiments to learn the truth.

An Experiment

I want to make a new extension table measuring (with trim) 29” x 36”. This extension table will be two layers of 3/4” MDF, in order to make a router base that will maybe stay flat. I envision cutting two pieces of MDF a bit larger than I need, gluing them together, then trimming them to exact size.

But how can I get very exact 90 degree angles, and exact sizes? The obvious answer is to use my table saw with the new fence… except that the standard setup yields a cutting capacity of 32” to the right of the blade, and I need 36. The instructions say that the standard setup give 14”-0” range on the left of the blade, and 0”-32” on the right.

So I have moved the rails 8 inches to the right, in hopes that this will modify the capacities to 6 – 0”, and 0-32” plus 8-40”. (The carriage arm does not give a 40” range, so wider cuts require moving the base.)

I plan to experiment with this setting for awhile, to see if I could be happy with that as my standard set up. I imagine I will, as I almost never make cuts to the left of the blade with a rip fence.

Since I have to live with having two ranges, it would be good to have stops set to quickly move between the two ranges.

A Problem I Haven’t Been Able To Solve

In setting up the 8-40” range, I cannot figure out how to precisely zero the fence. The fence won’t reach the blade. I could cut a strip of a specific width, then measure, and turn the micro-adjust the same number of clicks of the error in mils. But I don’t have a precise tool that can tell me how close it is in mils (thousandths of an inch), because my calipers only go to 6 inches.

The closest solution I’ve thought of:
  • set the 0-32” range precisely using the standard methods described in the manual
  • cut a strip of wood to 8”. This should be correct +/- 2 mils.
  • move the base unit 8 inches to the right.
  • place the 8” strip against the blade
  • move the fence against the 8” strip
  • set this to zero

This solution should give me accuracy of 1/64 to 1/32”. I’d like to do better. Any thoughts?

-- Mark, hack amateur woodworker, Medford (greater Boston) MA



7 comments so far

View PurpLev's profile

PurpLev

8523 posts in 3115 days


#1 posted 09-01-2010 02:55 AM

here’s another question to consider – I assume rips wider than 32” would be made seldom. in those cases – do you need to be 0.001” precise? or as long as all the rips are the same size shouldn’t that be satisfactory?

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

View Mark Colan's profile

Mark Colan

209 posts in 2312 days


#2 posted 09-01-2010 04:12 AM

@PurpLev: I have been asking myself exactly that question. I probably do not need .001” precise for big pieces, but if I could have it, I’d like it. Call it OCD. But I would like better than 1/64” (which is about 16 mils). I guess the cuts WOULD be the same size, assuming I set a stop for the long range, which I plan to.

But the reason I want the extra capacity is that I think such cuts might not be so rare, as in when I am building cabinets. When working with plywood, a rip fence can be also used to cut to length. In the case of this table, which should be a finished size of 29×36”, I AM talking about cutting to length. Technically, it’s a cross cut. I don’t see danger in doing this. Do you? It’s much easier, and probably safer, and certainly more accurate than using an Incra 2000 cross-cut fence.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA

View Bob #2's profile

Bob #2

3809 posts in 3488 days


#3 posted 09-01-2010 03:05 PM

A couple of suggestions:
1. Do a couple of small projects to see if your saw is producing the accuracy you need.
2. Consider upgrading from what is essentially a jobsite saw to a cabinet saw if your are still concerned with accuracy at that point.
Many contractor saws are pretty good at accuracy but now compare with a decent cabinet saw.
For a start they don’t have the power to be consistently accurate with large stock.
If you are ripping stock more than 32” wide on your table top using the fence as guide you are asking for a kickback. That’s very dangerous.

-- A mind, like a home, is furnished by its owner

View PurpLev's profile

PurpLev

8523 posts in 3115 days


#4 posted 09-01-2010 03:17 PM

there is no danger in “cross cutting” plywood with the rip fence on a TS regarding grain direction, but as Bob mentioned – the extra width will make it harder to control the pieces accurately – and could potentially create a kick back.

if you are planning on using this to build cabinets, and need wide/tall cross cuts – I would highly recommend forgoing the use of the rip fence all together and build a crosscut SLED that would hold the large parts, and allow you to position stops (Incra fence/stops? or shop build) to get your desired sized cuts. much safer (the sled rides on the table/miter slots and you don’t have to keep the cut parts perfectly parallel to fence), much easier (plug and play for multiple cuts).

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

View Mark Colan's profile

Mark Colan

209 posts in 2312 days


#5 posted 09-01-2010 03:33 PM

Thanks to both Bob2 and PurpLev for alerting me to a danger I was not aware of.

Mostly I do NOT try to rip a full sheet, because they are heavy and hard to control. I either get them with one rip cut to a size just larger than what I need, then rip to trim to exact size, or I put them on a sheet of foam insulation as a backer on the floor and use a guided circular saw.

Here, my plan to “rip” greater than 32” is really to trim to length: it is a cross cut, and only 29 inches wide, not the full width of a sheet.

I did build a sled for getting uniform size shelves, but it is only about 16” wide inside. Longer than that and I have an infeed problem. I suppose that could be solved with infeed/loutfeed tables.

So maybe my project ideas are pushing against the constraints of my relatively small shop. And maybe my goal of pushing the capacity of my table saw from 32 to 40 inches is pushing the limits of safety.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA

View PurpLev's profile

PurpLev

8523 posts in 3115 days


#6 posted 09-01-2010 03:52 PM

yup. thats why cabinet shops, and shops that use sheet goods usually have a sliding panel saw (can cross cut 48” sheets with ease). not saying all do, but from my experience – most do.

As for dealing with sheet goods – unless it’s manageable sizes (read – small cabinets, and drawers) I’ll do all my cuts with a circular saw, a good blade (I have a 40tooth freud Avanti blade which gives fantastic clean cuts) and an alumunum straight edge on top of a sheet of MDF to act as a backer board. I end up with final clean cuts this way, and don’t even need to trim or clean it up usually.

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

View Mark Colan's profile

Mark Colan

209 posts in 2312 days


#7 posted 09-02-2010 03:05 AM

Ok, I figured out the solution to my problem. To get perfect “zero” setting for the 8-40” position:

1. Rezero for the 0-32” position. If it’s already there, you don’t need to do it again. The red handle should be in the locked position, and it should be pointing at 0”.
2. Clamp down the fence at this position, by tightening the knob at the front end of the fence. Optionally set the floating stops in front and back, so you can return to this quickly.
3. Set the red clamp to fully unlocked position (all the way open)
4. Loosen the knobs and set screws on the base
5. Pull the base away from the blade until the pointer in the LS Positioner window says 8”.
6. Tighten the knobs and set screws on the base. Optionally set the fence stops.
7. Move the metal ruler on the magnetic strip to position it so the point shows 0”, but remember to add 8” to every reading on the ruler. Or: get the plastic scales from Incra that were designed for exactly this purpose, get them set correctly, and read the scale directly.

At this point, the LS positioner is set as exactly to the 8-40” range as it was for the 0-32” range, that is, probably within 1/1000 or two. Also, if you set the hard and floating stops, you should not need to rezero when you go between these two ranges

I felt SO clever to figure this out! Until I read Mark Mueller’s email reminding me that something similar was documented in the instructions he sent me, which are also right here. The difference is that I am describing how to change the range from 0-32” to 8-40”, and his instructions change it to 20-52”.

-- Mark, hack amateur woodworker, Medford (greater Boston) MA

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com