MFT accurate cuts

[NewbieRaf]

Hey All

I’m making my first cabinet and it dawned on me that I’m measuring, marking and lining up with the cut line or splinter guard which obviously can not always be consistent or accurate.

I’m wondering what other people do aside from using the flag stop to get exact cuts?

I’m including the great @petermillard as I know he’s an mft guru

thanks

 

[porker]

I have an MFT type top but no fence, just the dogs and the rail. I just clamp an offcut on the table as a stop to get repeatable cuts

 

[petermillard]

Hey Raf. Lots of ways to do this, and rather than second-guess with lots of ifs, buts and maybes, can I ask if you're actually using an MFT with fence, flagstops etc..., or just an MFT top with eg rail dogs or tall Benchdogs, or no MFT top and just a rail square, or Just the saw and rail? Thanks! P

 

[Britman]

I'm very new to using an MFT and I only have dogs and few lengths of extruded aluminum that I use as a fence. Then for repeatable accurate cut its a combination of dogs and off cuts to give me a stop. Can be a pain having to size the off cut to give the right stop for any given piece, if that makes sense.

 

[NewbieRaf]

Hey All and @petermillard my mft is with the fence and angle guide that it came with. To give you guys a better idea my workflow is the waste board is always to the right of the track. So yes I could put a stop or a dog on the left (or in the table) but that would mean measuring from the cut line or splinter guard to the stop - I’m sure that’s not the best way.

the other way I’ve done it is to cut a scrap piece until the perfect dimension then flag Stop or use dogs on that but something tells me I don’t have to do all that faffing around - there must be another way right?

 

[MikeK]

Maybe I've been lucky, but I've never had a reason to distrust the edge of the splinter guard on any of my guide rails. I have a roll of replacement splinter guard on hand in case the splinter guard on the guide rail is damaged.

 

[Doug71]

I don't have an MFT myself but hear some people say a slop stop improves accuracy but other people say they are not needed if you always push the saw to the same side?

https://picclick.co.uk/Tune-your-Festool-MFT-rail-with-Slop-Stop-273137784779.html

 

[NewbieRaf]

Thanks both, maybe it is just me and a matter of running my tape measure from the splinter guard. Maybe @petermillard has some tricks up his sleeve - - we will see

 

[petermillard]

Thanks for the update. The way I do it is to measure the width of cut on your workpiece, set the mark against the splinterguard, set the flagstop against the back edge of the work, and make my cuts. They’ll all be consistent.
I’m sorry, but I don’t understand why you can’t trust your splinterguard? It’s on the edge of the cut line, unless it’s very old and worn - in which case replace it, or move it and recut it.

I do use a slop-stop btw, because over time the steel pin that the rail locates on can wear a slight groove in the aluminium, and cause some slop; the (delrin??) slop stop helps prevent this.

Hope that helps. P

 

[NewbieRaf]

It does thank you Peter - - in the sense that I now know that I’m not going mad. I’ll have to dig deeper into why my last cuts on the cabinet were a mm maybe 2 out - - yes I’m a perfectionist to my detriment haha

 

[petermillard]

It does thank you Peter - - in the sense that I now know that I’m not going mad. I’ll have to dig deeper into why my last cuts on the cabinet were a mm maybe 2 out - - yes I’m a perfectionist to my detriment haha

When you say 1 or 2mm out, do you mean inconsistent ie between boards that should be identical, or 1 or 2mm different than what you were expecting? If it’s inconsistent, then there’s something else going on eg the workpiece moving, or the rail moving, or the saw not snugged onto the rail. With a properly set up MFT you should getting much finer tolerances than that.

 

[NewbieRaf]

Inconsistent between boards. Yes indeed this is what I am thinking also a. To be honest I was rushing a little so that could be it but I need to find out the exact cause. I may try and do that tomorrow and keep you posted

 

[NewbieRaf]

Oh one question - should I allow for kerf of the blade? @petermillard?

 

[petermillard]

Oh one question - should I allow for kerf of the blade? @petermillard?

Not if the waste is to the right of the rail, you should be able to line up the mark against the splinterguard, and that’s where the cut-line will be.

 

[NewbieRaf]

Thought so thanks again peter. The weird thing is I cut some shelves last week for that kitchen no issues at all

I’ll get to the bottom of it

 

[NewbieRaf]

Hi again all

Weirdness is occurring so I decided to show you by means of a 2min video, please see below.

I decided to make some test cuts to make sure that the cut is actually the length and width that I am expecting. I cut the length of the board, no issues and the result was accurate. When cutting the width of the same board, its about 1mm out. Here is the link:



@petermillard for his thoughts

The only thing I can think of is the width of the splinter guard is not even - Just thought of that, need to check

Thoughts???

 

[Simon89]

Three things I would check:

try measuring with the tape as straight and flat as possible, twisting And flexing it over your rail may produce some inaccuracies.

check your tape is accurately measuring using both faces of the hook/end, if the tape is worn, damaged or cheap this may be a source of inaccuracies.

I would also do a test cut by:
1. Mark 249mm & 250mm on the material
2. Set your stop to 250mm
3. Cut the material
4. Check where the cut was before lifting the track in relation to the splinter guard & your line
5. Remove the material and have a measure up. By having marked 249mm you should have a reference point if your pencil line @ 250mm has been cut away.

 

[niemeyjt]

Is the saw tight to the rail and correctly fitted to the rail?

 

[Doug71]

It's because you are using your tape measure wrong, you should be pushing it against the flag stop not pulling it tight.

Tape measures have a couple of mill "give" in them for if it's an internal (pushed against something) or external (hooked over something) measurement to allow for the thickness of the hook. When measuring from the flag stop to the splinter strip you should be pushing the tape towards the flag stop but in the video you clearly say "Pull it across".

If you push the tape towards the flag stop your measurement will be longer than if you are pulling it away.

What do I win ?

 

[niemeyjt]

But he said "Inconsistent between boards."