Author Topic: DW788 type 2 blade tensioning  (Read 3674 times)

Spartan scroller

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DW788 type 2 blade tensioning
« on: December 23, 2014, 05:42:01 pm »
Having a problem tensioning the blade on my DW788 type 2.  The cam doesn't grab like it used to when I try to tension the blade.  Used to stop at 3.5 or 4 on the scale.  Now having to tighten the cam all the way to the end. Is the gear wearing out? Is this a repair I should be able to do my self? Has anyone else had this problem?

Regards
Terry

Offline jscott2

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Re: DW788 type 2 blade tensioning
« Reply #1 on: December 23, 2014, 11:12:20 pm »
Terry, not sure why the tensioning has changed, perhaps something is worn inside.  Rick's site http://www.scrollsaws.com/ might have a fix.  On the left, scroll down to, and click on "Dewalt Tuneup".  This takes you to a long page with a lot of reading about the 788 - adjustments, modifications, etc., and there are instructions on adjusting the tensioning rod.

Hope this helps.
Jim
Using a Delta 40-690 in the Montreal, Quebec (Canada) area

jbrowder

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Re: DW788 type 2 blade tensioning
« Reply #2 on: December 24, 2014, 12:09:21 am »
I'm having the same problem with my DeWalt. I know that if you can get to it, there is a rod inside the upper arm that is connected to the tensioning device. If you can gain access to that rod, it can be adjusted. I started to attempt this, but became too much of a scaredy cat to continue. Not sure what to do next.

Jim

Offline jscott2

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Re: DW788 type 2 blade tensioning
« Reply #3 on: December 24, 2014, 09:03:13 am »
jb, the link I mentioned above has a write-up and, on the same page, a bit further down, there is an exploded diagram of the tensioning area with instructions.  To get at the tensioning rod, you have to remove items 71, 26, and 80.  With a bit of careful tugging, you should be able to lift 71 enough to continue. 

This http://servicenet.dewalt.com/Products/Detail?isId=true&productNumber=DW788&selectedType=21612 page has parts diagrams, the "default" shows the area you are interested in.

When you take it apart, don't miss-place the washer, item 87.  I also found that bolt 52 tended to loosen as the tension knob 26 is turned.  A little blue Locktite solved that.  (Don't use the red or you will never remove the bolt again.)

It can be scary to take it apart but if you work carefully (take pictures of each step if you want) you shouldn't have any problems.

Good luck,
Jim
Using a Delta 40-690 in the Montreal, Quebec (Canada) area

Spartan scroller

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Re: DW788 type 2 blade tensioning
« Reply #4 on: December 24, 2014, 09:57:03 am »
Ya know I just have to laugh at myself sometimes? I forgot to mention that I had an
Easy Lift bar attached to the upper arm. When I unbolted it to take off the switch cover it occurred to me that maybe that bar wasn't letting the arm go all the way down into position. Sure enough that was it. I tried a blade with the bar disconnected at VIOLA! I have plenty of blade tension now! I love it when simple solutions present themselves!
Thanks everybody for your help and a very Merry Christmas to all (and to all a goodnight)

Regards and HO HO HO,
Terry

Offline jscott2

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Re: DW788 type 2 blade tensioning
« Reply #5 on: December 24, 2014, 10:20:39 am »
Terry, glad you found a simple solution.  I also have an Easy-Lift.  When I install the blade, I fist put the balde in the upper holder, then push the upper arm down to the bottom of it's stroke, then reach under and push up on the lower arm while I tighten the thumbscrew under the table.  Works for me.

Jim
Using a Delta 40-690 in the Montreal, Quebec (Canada) area

 

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