DeWalt 788

[Fretnot]

Hi Everyone. I have a mark 1 788 and up until recently I have never had a problem with it but I have one now and I would be grateful if you good people can maybe put a finger on what is causing the problem.

I am using FD blades as I always have, not that they are the cause of the problem. After putting a new blade in I start cutting and then after a few seconds I have to stop the saw and when I release the tension lever there is a big bow in the blade where it has become quite slack in such a short time. I can always tell when I need to stop the saw by the sound from the saw. Its quite frustrating as I cut maybe an inch into the wood then I have to release the tension, undo the top clamp and re-tighten. I have looked at the thumb bolt and it still looks brand new. I just cannot figure out why I am having this problem.

[Hawaiilad]

Perhaps you need to clean the oil off the ends of some of the blades you are using and/or you need to take out the tension thumb screws and take a little sandpaper to ends. It sounds like your blades are just slipping when you tension them up.

[ubgoofy2003]

I think I would have to agree with Larry, that the blade is slipping, but, not coming all the way out of the holder. Then, with the blade so loose, it will bend it. You're lucky it isn't breaking the blade. Well, not really lucky, but, it could break if that is what is happening. I have never had to clean the blade ends, but, I have taken the thumb screw out & filed the swivel part of the holder, so that it is smooth & flat. Hope you can work this problem out without any expensive repairs. Good Luck

[Bill Wilson]

Perhaps your tension mechanism is slipping. Take a look at the DeWalt tune up section of Rick Hutcheson's website. I think there is some info there about how to check & adjust the tension mechanism.

Rick's Scrollsaw

[Steve_S]

Never had that on an FD and I never remember to clean or scuff the blades.

But some other things to consider, take the thumb screw out and scuff the end of it so it isn't shiny/slippery, make sure you leave it flat. It can get polished and not have any friction on the blade when clamping. I do the same to the allen screw side also.

Make sure the left side allen screw of the blade holder isn't below the casting surface. Just look in the notch and make sure the blade can rest on it when clamped. This will sometimes show up with the blade having a dimple on it when you are done cutting. If it is below, then the thumb screw is trying to clamp the blade against the casting which isn't anywhere as strong a clamp.

Lastly, if it is a "small" blade like 2/0 then check to make sure the thumb screw and allen screw are getting enough surface to clamp on. On my DW there is a small clearance behind the two screw surfaces and I found the 2/0 was only being clamped by its front half. Now I use a small needle that I space the 2/0 blades forward so they get full clamping.

Ricks Scrollsaw is a great resource.

Steve.

[Fretnot]

Many thanks to Larry, Ubgoofy, Bill and especially toSteve for your very fine detailed reply. I am so grateful. I tank God it was nothing serious, in fact it was the most simple thing imaginable. Over the years there has been a build up of crud for want of a better description and as it was mainly grease and oil the blade was slipping. I cleaned off the ends of the thumb bolts onto sandpaper and was amazed that as I rubbed them square to the sandpaper black lines appeared. Now it is all like new and the blades are holding fine. Thanks again guys for taking the time to reply.

[sawman101]

I experienced the blade slippage problem, as have many others. Even after dressing the end of the thumb screw, and sanding the ends of the blades, they were still slipping. To remedy this problem, I took a piece of 1/4" thick wood, roughly 1/2 to 1" wide and 2 or more inches long, drilled a hole near one corner that alowed the thumb screw to be threded into. Turned the screw in until it is just protruding through the wood, then I dressed it on the disc sander, with the table set square. Or, you could use a file to dress the screw end flush with the end of the piece of wood. I've had no more blade slippage.

[Paladin]

If you do take out the set screws on the blade holders, I suggest reapplying some blue loc-tite to the threads.