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DIY Dewalt 788 table ....

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  • DIY Dewalt 788 table ....

    As a most of my regular contacts on the forum know I recently imported a 220v model DW788 Type 1 scroll saw into Mexico, my home country, which I bought second hand in Italy last year whilst working there.

    In view of exorbitant shipping costs and the threat of having to pay a large import duty if I freighted the saw to Mexico I decided to risk bringing it into the country on my return home in my check-in luggage. The only problem was that due to recent changes in check-in luggage allowances to Mexico it was going to cost me up to 200 USD in excess baggage charges if I couldn't reduce its weight somewhat. With this in mind I decided to 'loose' 22 lbs of weight by leaving the cast table in Italy and make a provisional one back at home until such time as I could bring the original back on a future trip.

    Having taken all the critical dimensions from the original table I decided to make my table from 18 mm MDF and support the backside of it with a ring of the same thickness material. Since MDF is fairly weak when edge drilled I fitted the rear of the table with an inset of hardwood to take the standard Dewalt table pivot pin. I tongue and groove glued this insert into the MDF then waxed the inside of the bore drilled for the pin in order that it would turn smoothly.

    I made a couple of design changes to my table from the original. Firstly, I changed the table shape to give me more working area surface and to make the rear of the table stronger. Secondly, I included an interchangeable insert around the blade hole to not only provide a very smooth cutting surface around the blade, using 6mm acrylic plate, but to allow me to easily switch inserts between a standard slotted one to a no-clearance one for when cutting small pieces. Also, since I have impaired sensibility in the tips of my right hand index and middle fingers from a table saw accident and often struggle to 'feel' my way when fitting a blade beneath the table, I can either see through this insert or flip it out completely to make changing blades really easy.

    I intend to provide a dust extraction system under the table, and probably over the cutting blade as well. I particularly want the system under the table since the Dewalt has no lower dust collection tray and the sawdust just trickles out from the tilt quadrant area onto the floor - definitely a minus design point in my mind.

    Having fitted the table my final move was to mount the saw on my homemade base which has an adjustable back to front tilt mechanism which I normally have set at around 6 degrees angle to minimize neck strain when cutting. I also intend to purchase a set of industrial use lockable casters for the base so that I can easily move it around.

    Now I just have to wire up a 110v to 220v transformer to power the European voltage motor the saw is fitted with and I'm be ready to start scrolling. Btw - thanks go out to my forum friends who offered advise on how to step up the voltage from 110v to 220v. After asking an engineering pal where I could buy such a unit in Mexico he gifted me an old Westinghouse 3 Kw transformer he'd had buried in his obsolete equipment pile for years. It was originally meant to step down from 480v to 110v but a trip to a knowledgeable local electrician sorted this detail out. It cost me all of 12 USD for his work to reverse the wiring which i was well pleased about. Apart from being free, as an added advantage, the transformer adds a hunk of weight to the base of my stand making it rock steady!

    The saw has been tested and works perfectly. I'm really happy with my table and the only sacrifice I've made from the original is that due to the thickness of the MDF I can only tilt it around 20 degrees right or left without the MDF fouling on the bottom arm. I know that I can engineer my way out of this problem if necessary but since I rarely use the tilt for anything more than 10 degrees I'm happy to leave things as they are.

    The funny part - most of my projects seem to turn up one annoying problem or another which you can smile at after the event and this saw table was no exception. I originally thought to cover the top surface of the MDF with a piece of Formica and did actually do this. After trimming the table edges the end result looked really neat - until the following afternoon! Mexican sun can show no mercy and during the afternoon my provisional lean to shed with translucent roof sheeting soared to around 40 degrees C (105F) - high enough to soften the contact adhesive I'd used to attach the Formica. When I opened the shed door the following morning I found that the Formica had curled up from all around the periphery of the table surface. It took me about 3 hours to remove the Formica and adhesive using mineral spirits and then apply several layers of Miniwax water based polyacrylic satin finish top coat direct to the MDF as a compromise. This may not look as pretty an end result but it does the job. Lesson learned - sometimes it pays to try to be not so smart - LOL!

    In resumen - another long tale over. Now I just need to clean out my shed to make some scrolling space and later in the week change the roofing for opaque insulated sheeting. No rest for the wicked !
    Attached Files
    Last edited by jim_mex; 05-21-2012, 08:01 PM.
    Jim in Mexico

    Logic will get you from A to B. Imagination will take you everywhere.
    - Albert Einstein

  • #2
    You are one very clever man!!! Don't you have a neighbor with a macine shop?
    If you do have him clone your creation in some 6061 Aluminum.
    I really like the clear window idea.
    Rolf
    RBI G4 26 Hawk, EX 16 with Pegas clamps, Nova 1624 DVR XP
    Philosophy "I don't know that I can't, therefore I can"
    Proud Member of the Long Island Woodworkers Club
    And the Long Island Scrollsaw Association

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    • #3
      I am going to have a buddy look at what it would take to machine the Jim-window in my stock 788 top.
      Steve.
      EX-16, DW-788, Dremel 1680

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      • #4
        Thanks Rolf/Steve -
        @Steve - find a shop with a big capacity lathe and get them to turn a circle out of the middle of the table about 3/16 " deep (according to the thickness of the insert you choose to use) and 2 1/2 - 3"" diam. Drop into this a circular piece of acrylic or plexiglass.. To stop the disk from spinning fit a small 1/8" diam pin on the circumference of the turned out boss so that half its diameter can fit into a corresponding notch in the inserted acrylic and that will do the trick. This system is similar to that used on my budget Delta saw except that the Delta uses a 1/8" thick metal insert. I much prefer the see through acrylic for the reasons I gave earlier, also I can easily cut new inserts on the saw if the original gets too damaged or worn.

        By the way, the reason I went for a rectangular window on this table was simply because it was easier to cut out the insert with my pocket router rather than use a centre point jig.
        Last edited by jim_mex; 05-21-2012, 07:57 PM.
        Jim in Mexico

        Logic will get you from A to B. Imagination will take you everywhere.
        - Albert Einstein

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        • #5
          Nice work around Jim.

          Steve I would recommend a milling machine over a lathe to cut a window in your table. Once you find a machine shop they will know what to use.
          Tim

          In God we trust, all others must pay cash!

          I don't want no bargains, they always cost me more money.

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          • #6
            Nice job ,would not be hard to make vertually dust free !
            M.V.B. Carl
            "Home Of The Dust Free Scroll Saw"
            Remember (IT is WHAT it IS)( Unless YOU change IT!)

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            • #7
              The ever resourceful Jim!!!!

              Good job mate.

              Rhys

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              • #8
                Nice table Jim. Did you make your stand? It looks very much like my Hegner stand.
                Hawaiilad
                Larry

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                • #9
                  Great stuff Jim...!!!!
                  So happy for you to have been able to get that baby home....
                  So what's the first thing you're going too cut on it???
                  Jim

                  The limits of the imagination are imaginary.
                  No task is too tedious for Art.
                  Rock and Scroll

                  My Gallery

                  My Website
                  Featherwood Woodcrafts

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                  • #10
                    Have you considdered a lexan clear top done basicly the same way recessed in a hardwood edge frame ,allowing you to see from any angle not covered small lite under
                    then manifold and vac and waalaaa all you need is upper vac adjustable pick up tee to
                    remote vac and all you problems solved! Lexan is bullet proof ! M.V.B Carl
                    "Home Of The Dust Free Scroll Saw"
                    Remember (IT is WHAT it IS)( Unless YOU change IT!)

                    Comment


                    • #11
                      Another thing to look at ,If you have frt.to back movement on your blades stroke shimming your angle gage to the table ,you can remove most not all ,but much more accurately and easier then other fixs while your modifing your table ,That was the real main reason for spiral blade failures backing up blade angle osilating back and forth on the saw stroke .M.V.B. Carl
                      "Home Of The Dust Free Scroll Saw"
                      Remember (IT is WHAT it IS)( Unless YOU change IT!)

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                      • #12
                        Did you make your stand? It looks very much like my Hegner stand.
                        Hi Larry - yep and it is my design and not copied from any commercial stand. I built it about 4 years back just after I started scrolling after reading on the forum that lifting the back edge of the saw up makes for much more comfortable scrolling. I went for three legs basically because my shop floor wasn't to level at the time and unlike the Dewalt tripod stand which has two legs at the back I went for two at the front because I felt it would give me more room to move my legs around under the table. The design is nothing too complicated but it is well made, heavy and extremely stable which is what counts.

                        So what's the first thing you're going too cut on it???
                        Hey Jim - my mark II balancing dragonfly design to put up as a forum challenge is waiting to be cut and gets top priority as soon as I can clear out the junk Norma filled my small workshed with whilst I was AWOL in Italy!

                        Have you considered a lexan clear top
                        If i thought I could source this locally that would be an interesting option but you have to remember Carl where I'm based. I'd probably have to steal the windows from one of the Mexican drug barons SUV's to get hold of that stuff.

                        Ref shimming to stop the front to back blade movement. I had thought of that but after checking the blade movement out it turned out to be pretty darn good. Probably more luck than judgement on my part but I'm not going to adjust something which at the moment seems to be ok - LOL!
                        Last edited by jim_mex; 05-28-2012, 07:47 PM.
                        Jim in Mexico

                        Logic will get you from A to B. Imagination will take you everywhere.
                        - Albert Einstein

                        Comment


                        • #13
                          Jim -- Gotta love the challenges you take on. Nice work at addressing the some of the design issues in the DW table. The insert is great! -- and I think the rectangular shape is better than a round one. The adjustable tilt mechanism on your stand is wonderful!

                          Thanks for once again sharing your resourcefulness with us.
                          Mtnman Jim

                          taking life as it comes and trying to make the best of it

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                          • #14
                            Thanks Jim - good to see you back from the ditch again. Thanks for the kind comments pal.

                            Btw - last night I was talking to our mutual forum pal Tim (evilbadger) and we came across another big advantage using the MDF table instead of a metal one.

                            During the winter months, because of our altitude, my shed can get pretty cold at nights and I remember several times having to wear cotton gloves because the cast metal table of my Delta was so darn cold to touch during the mornings. MDF is definitely a better alternative from this point of view.

                            Btw - ref my experience with the shed overheating.
                            I ripped off the old translucent fibreglass/acrylic panels this weekend of my very low roof , fitted a white painted metallic lamina roof and lined the underside with 1" styrofoam sheeting. I now have a much cooler workshed and hopefully a warmer place to work in winter. Now its back to the final cleanup and and getting my work area organized so I can finally start scrolling again.
                            Last edited by jim_mex; 05-28-2012, 09:41 AM.
                            Jim in Mexico

                            Logic will get you from A to B. Imagination will take you everywhere.
                            - Albert Einstein

                            Comment


                            • #15
                              Great project. Thanks for sharing with us. You are very resourceful indeed. I noticed on your European version the dust blower is on the opposite side from my 788.
                              "Still Montana Mike"

                              "Don't worry about old age--it doesn't last that long."
                              Mike's Wood-n-Things LLC

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