MFT and large or small cuts

[Raymien]

I’m not a professional joiner, but I make radiator covers and other smaller pieces of furniture in my spare time. I want to build a new workbench in my double garage, and I want to incorporate an MFT style top to help with cutting square pieces of stock. I already have a track saw.
The table will be the size of a full sheet, however I’m in two minds whether I want to put dog holes in the whole top, or only a portion of it. I’m considering buying an MFT replacement top from a CNC company, and adding this to one side of the workbench, but I want to be sure I accommodate all my needs from the start.

To help me decide, I wondered if you guys with more experience of using an MFT could answer a few questions please:

1) Most of the stock I need to cut is in the region of <1200mm x 100-160mm. Am I correct in assuming anything larger than that will need dog holes down at least one length of the workbench too? To cut a piece that size from a full sheet of MDF for example?

2) How would I take a full 8’x4’ sheet, and cut a piece 1600x200mm accurately and squarely? Am I right in thinking I would need a rail longer than the standard 1400 festool one, and dog holes/dogs far enough apart to cut the width from the long side of the sheet at ~210mm. I then trim square on one edge, and then use these two square sides to cut the other two sides to the correct measurement? If so, would I not need dog holes >2440mm apart in order to fit the sheet in between them? Therefore my bench needs to be larger than a full sheet? Or am I missing something?

 

[sometimewoodworker]

Depending on the number of times you need to cut 1600~2440 you have no need to use dog holes for accurate cutting.

I rip for length parallel then trim for accurate square on the short cuts. The bench has no need to be under the complete length of the cut for the parallel cuts. Mine is 1700 long and I’ve ripped many sheets on it. So are you missing something? Yes.

You absolutely need rails that in combination are longer than the cut you are going to make. I use a 1,440 + a 1,080 and an 800 rail for a 2,440 cut using a Betterley Straightline Connector when joining the rails to guarantee perfect alignment each time.

If you are doing these cuts all day long then these are the wrong tools. If you’re going to breakdown a lot of sheets and your workshop is huge then a 3,000mm bench is needed.

I could afford a 3,000 rail but the local importer will not guarantee to get it to me from them perfectly straight and a 1,300km round trip drive to pick it up is just too much, so I’m doing the next best thing.

 

[Mrs C]

For larger pieces a rail square and some parallel guides (even if the are home made) works well for me as it reduces the handling of the board as I struggle with large pieces.

If you are careful you can get away with moving the rail for cuts longer than the rail, but it’s easier with a longer rail.

The MFT will come into its own for smaller pieces when it is more manageable to move the board than the rail. MFT standard size is something like 1100x700 so not really designed to cut very large pieces.

 

[Raymien]

Thanks for the replies guys. I’d say 90% of what I will be cutting will be under 1200mm, so I can happily cut the full sheet down and work away with the MFT at one end.
It’s just occasionally I’ll need to make a piece which is 1600mm x 200mm or similar, and so I thought adding dogs across the long side of the bench top would to assist with keeping longer rail rips square too. Naturally I’d need rails long enough, and so was considering the Youtool 3m, however I’m guessing that’s the one you’re referring to that can’t be guaranteed to arrive straight. So the connector you refer to is useful and I’ll look into it. Thanks

 

[harryc]

I assume you will be doing a lot of repetitive cuts for the same length, in which case get yourself a bench fence with a stop incorporated for accurate repeat cuts.

https://benchdogs.co.uk/