Howdy, Are you saying the bottom holder is not holding? If that is the case, try sanding the holder on the side that touches the blade and also sand the opposite side. This usually helps me.... Hope this helps, Mark

Well I tried that but my blade is still coming out. I put the blade in & tighten dont hardly get started & the blade comes out of the bottom tightner. Any more help would be appreciated.       Linda

I lightly sand the ends of my blades before inserting them.  Also pull the screw used to tighten the blades and make sure it isn't pointed.   Any chance you got some wax or some sort of oil down in that area?

Ive tried all these things & it still is doing it . HELP

Might be time to order some new clamps and set screws. You can order them from

here http://www.dewaltservicenet.com/ServiceNet/logon.asp if you have no place to get parts locally. You have to register first to access the site. Part Numbers are Knob Assembly/Clamp 286303-00 and Set Screws 286301-00. You need two of each (one each for the upper clamp and lower clamp).

When I ordered some I got a couple of sets so I would have some on hand.

 

Tom

ok I ordered the new parts and have received them. Now can you tell me what I need to remove the set screws?

Linda,

You need a 3mm hex key to remove the set screws. There should have been one included with the saw if you bought it new. Otherwise a trip to the local hardware store may be in order. May be a little hard to remove as there is thread-loc on the set screw to keep it in place. Also you should put a drop of thread-loc (loctite) on the new one when you put in.

 

Tom

Thank You all that have helped me. Ive got everything now so wish me luck.lol

Red,

Let us know how things turn out. Make sure the new set screws protrude the same on both the bottom and top clamps and check your table to make sure it is square with the blade after you are done.

 

Tom

Thank you all it works lol.  thank you so much

I've had my 788 for a couple years and it has always driven me crazy with the blade slipping in the bottom clamp.  I'd tried wiping the blades with laquer thinner, sanding the blade ends, sandng the set screws and anything else I'd read on the posts.  I'd talked to the DeWalt guys at the wood shows and they say they'd never heard of the problem before.  On one of the posts somewhere, maybe on this site, but I can't remember where someone said to oil the threads on the thumb screw.  I tried it and it seems to have fixed my problem, the blade is staying tight.  I'm in a high school and they guys are finally able to use it with me always on them about tightening the blade. 

 

I have no idea why it worked, but my blade stays tight now.