Bevel Cut with TS75 - not straight

[phmade]

I'm cutting a 45degree miter with my TS75 through 1-3/16" White Oak.  I thought the saw would handle this fine but it really seems to be struggling.  I have a sharp blade on the saw but at the beginning and end of the cut the saw seems to "dive".  Has anyone experienced this before?  I really need this to be straight since I'm mitering another piece onto it.  I'm attaching a couple of images to help clarify. 

 

[semenza]

Wow thats kind of wacky  ???

Both ends of the cut?

Could the rail have shifted  after you made the plunge because of the sidewards force on the handle due to the bevel?

Did it only cut that way the one time is this a consistent problem?

Seth

 

[lino-man]

I'm wondering if it's because the clamps were holding the real really tight. did you use clamps when making the cut?

 

[phmade]

Both ends of the cut are affected but the "exit cut" side is much more severe.  I have everything clamped so I'm sure the rail isn't moving and I'm really concentrating on my technique to make sure it's not me.  It's happened before but I wasn't doing anything so precise so I didn't really investigate.  This is for a dining table and I don't want any wood filler on my miter!

 

[harry_]

my first guess would be that the material was not adequately supported.

 

[Rick Christopherson]

Harry is on the right path. What is most likely happening is that there are areas where there is a gap between the saw and the workpiece. This will move the bevel cut sideways. In addition to that, the force of the saw moving sideways is pulling the guide rail with it.

 

[Mike B]

Was the end of the rail supported?

My guess would be that if you ran the saw completely through the cut, that the weight of the saw pushed down on the unsupported track. With a bevel cut, that could easily deflect the back of the blade into the work.

 

[phmade]

The material is definitely supported - and flat.  The rail end isn't supported so I'll try that but I'm skeptical because I'm pressing on the saw plate over the supported section.  Maybe I should just try to use a router with a 45 degree bit.  I know that will work if I can find a 45 degree bit that's big enough.  Does anyone know of one that will work for 1-3/16" thick material?

 

[tjbnwi]

I'm with Mike on this one. The rail dropped as the saw exited, it changed the cut point.

Support the ends of the rail.

Tom

 

[Michael Kellough]

I'm with Mike on this one. The rail dropped as the saw exited, it changed the cut point.

Support the ends of the rail.

Tom

I'm with Tom, on a bevel cut the weight of the saw is cantilevered off the rail already. As the saw transitions to or from a supported or unsupported rail the rail will twist allowing the saw to over cut the work. More-so with the larger heavier saw.

If you have similar results with a well supported rail then you should look for burning on one side of the blade which would indicate a toe-in misalignment and/or a riving knife that isn't positioned correctly.

 

[CharlesWilson]

I have made 45 degree bevel cuts using the TS75, but with difficulty. I did test cuts first, and noticed some irregularities, and finally determined that the cantilevered weight of the saw was primarily responsible for them. The TS55 is much better balanced for this type of cut.

It may not be pretty, but you could try clamping some weight to the left side of the saw on a short lever arm to better balance the saw for this cut. Maybe Festool should have an accessory to do that in a more graceful manner.

Charles

 

[peter halle]

One accessory that can help you - I use the corresponding one for my TS-55, is the Parallel Guide.  The image below shows it in it's normal usage, but if you remove it, flip it upside down and then insert from the other side of the saw, then it becomes an outrigger where you can place a hand for extra support.  You can also flip it upside down and insert it into the blade side and it will prevent tipping - if you enough material for the bottom edge to ride on.  Another double usage for an accessory.

Peter

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[phmade]

I finally had some time for closer investigation.  It turns out that it was a combination of a few things.  Most importantly, the workpiece had a slight bow which was greatly exaggerated when beveling the entire surface.  It make sense when mitering a sharp corner with a .015 or .020 bow results in a huge dive at the end of the cut.  Also, the guide rail wasn't supported as well as it should have been at the end of the cut.  

I ended up cutting the miter on my table saw and I'll try to avoid using the TS75 for big bevel cuts in the future.  It just seemed awkward... I don't have a TS55 but I think it would be more comfortable although with a greatly reduced depth of cut.  Thanks for the responses and suggestions!

 

[butzla]

I had the same problem while making miter cuts on a cherry humidor I made.  It was very frustrating and spent more than an hour trying to set it up.  In the end, I went over to the table saw and spent a minute setting up the miter gauge and cut flawless miters first try.

 

[Paul G]

A good example why my future shop will include a nice table saw. I like my track saw but some things are better done on the table saw.

 

[phmade]

I'd really like to try a TS55 and see if it was more comfortable on a 45 degree bevel.  Although - the TS55 doesn't have the depth capacity that I need at 45 degrees...
Either way, I'm thrilled with my TS75 and all of my Festools.  Sometimes I complain that they won't do something that a sliding table will do and then I realize the $20k price difference!