New MFSlab table built!

[donwon]

So I thought that the MFSlab table would be a good addition to the shop.  Something I have been looking for, quick setup / tear down, able to cut 4 x 8 sheets, good for clamping and working on boards as required, etc.  I have looked at things such as two MFT tables, the MFT cart and the Paulk setup.  All very good ideas and have excellent uses, however the slab was something that could be built very easily and quickly.

I bought a piece of 1" MDF .. wow it is heavy!  Found someone through Kijiji who would machine the top and used my existing saw horses.  I have attached a picture of it to the message.  I have to customize the second shelf to fit my saw horses but not a big deal as that means I get to make more sawdust  [big grin]

After machining the top, the holes are made according to the plan .. 20.1 mm.  I have some dogs and clamping elements that I tried.  The festool clamping elements fit snug but the dogs I have, fit but I have to push them back out with a piece of 3/4 dowel. 

So I have some silly questions but please do not roast me too bad [crying]

1. Should the dogs fit that tight?  I do not know as this is the first I have tried them.  To fix the holes what is the best solution?  Live with it and bring a dowel and hammer, ream the holes, etc.  I have the 20mm forstner bit from the festool set but do not think that is the best way since it is an existing hole and forstner bit are not good at this. 
2. The dogs do not seem to have a leading chamfer on the edge that inserts into the slab (picture attached).  To me a 1/16 chamfer would help guide them in and there is plenty of material left to provide stability.
3. I have to round the back of the holes as the Festool clamps will not fit.  This has been mentioned before on this site.  My question is why would the top holes not have a 1/32 chamfer routed also.  It would help guide the dog in.  Again still lots of wood to provide stability.

Any other comments suggestions are more than welcome.  I can barely wait to try this puppy out!

 

[Vondawg]

How about the 3/4 dowel chucked in your drill with adhesive backed sandpaper wrapped around it....seeing how it's so slight (tight) a fit.
Looks great !

 

[overanalyze]

When I had an Mft top made I had similar results. I did chamfer every hole just a bit. That helped but they were still a bit to tight. Not wanting to deform the holes I started looking at my bits and tools.  I had an old worn 3/4" wire brush used to clean copper fittings before soldering. I cut the handle off and chucked it up in my drill. Ran it back and forth quickly in a couple if holes. It worked great for me. Did all the holes real quick and didn't have any more issues. Might work for you too.

 

[nclemmons]

Agree on using a dowel with sandpaper or finding a small drum sander that is 3/4" that you can put in your drill.  Should not take much sanding at all to loosen them up.

You could chamfer the tops of the holes slightly with a chamfer bit to maybe 1/16"  Given it is 1" thick, you have plenty of material holding the dogs.

If you have access to a drill press or a lathe, you could chuck the dogs in and use a file to chamfer the bottoms of the dogs as an alternative.

Top looks great!

 

[rmwarren]

donwon, that looks to be one of my Rip Dogs. They are speced at 19.9mm and so far as I know there haven't been any issues with them fitting standard MFTs.

This may not be much help but my hunch is the holes turned out to be undersized from your 20.1mm spec. You may want the ask the CNC shop to correct it if possible, although the I doubt they could without starting over.

RMW.

 

[donwon]

Hi Richard,

Yes they are your dogs. I am not questioning the dogs as they are excellent quality  except why there would not be more of a chamfer on the leading edge. I believe it is more with the top causing my problem.

Thanks for the feedback and gives me some ideas on how to fix. I was going to take a chamfer bit with guide bearing to the top and then a round over with bearing to the bottom will let you know how it goes

 

[donwon]

Well I have been playing around with the top today and put a small chamfer on all of the holes along with rounding over the bottom.  I have attached some pics for viewing.  I also had a round file / rasp which with a couple of strokes took off enough material for the dogs to fit quite nice.

I am starting to like this table as you will see the dust hose and extension cord along with clamps all fit nicely!

 

[johnredl]

That's great. Sorry, but I really don't know...in the 2nd pic, what's the smaller MFT for?  Smaller cuts?

 

[NL-mikkla]

That's great. Sorry, but I really don't know...in the 2nd pic, what's the smaller MFT for?  Smaller cuts?

It's a shelf that could be used underneath the slab!

 

[donwon]

Yes it is the shelf for underneath which houses your tools while you work above.

I used the bottom as my test piece so the top was perfect.

 

[johnredl]

Thanks

 

[DaleB]

Well I have been playing around with the top today and put a small chamfer on all of the holes along with rounding over the bottom.  I have attached some pics for viewing.  I also had a round file / rasp which with a couple of strokes took off enough material for the dogs to fit quite nice.

I am starting to like this table as you will see the dust hose and extension cord along with clamps all fit nicely!

Hello Donwon....
Read with great interest your option for changes to the holes top and bottom.  I'm about to get the CNC started on my MFSlab here in Australia and would love to know what the details of your bevelling on the bottom of the holes was.  Did this allow the use of the Festool hole clamps in 25 mm thick MDF?
And what was the hole diameter that you finally settled on? 20mm or something else? I'd really like to use the Festool range of dogs and other fixings. (The disease must have set in already!)
Many thanks for your thoughts and pix so far.. Really appreciate it.

 

[Tayler_mann]

I found I like to keep my holes tight (no pun intended). After you use the same hole a few thousand times with dogs for doing square cross cuts they tend to slop out. I like getting them so the dog just barely pushs in there and needs help from the bottom to get back out. I figure the tighter I start the better they stay. I have a few Ideas for my next top which I am making his week but not sure yet how they will work. I plan to sit with my CNC and 6 of my dogs I machines and get the best fit.

What happened to you is whoever CNC'd the top had bit deflection at the end of the cut. So basically your holes might tend to be a little oblong by .1 - .3 mm. I had this with my first top I made. If you look I'm guessing you have a little part of the circle that isn't perfect and has a small ridge. When machining if you don't do a clean up pass there is a good chance you get that. The other possiblty is that the mdf expanded slightly. I've heard of that being an issue. Ive never seen it myself.

What are the larger holes on the sides used for? I have always been curious about that.

 

[Amalix]

What are the larger holes on the sides used for? I have always been curious about that.

They are intended to put the head of a clamp in, so you can clamp workpieces to the sides.

 

[Tayler_mann]

What are the larger holes on the sides used for? I have always been curious about that.

They are intended to put the head of a clamp in, so you can clamp workpieces to the sides.

I see, why do that over having the holes closer to the edge if it's custom CNC'd? I have 12 Mft clamps (6 short and 6 long) and also two sets of elements. For me I'm not sure if it would pay however you can always use one more clamp at times. Do you have any pictures of examples with them in use? I'm just trying to think of applications where it would come in handy more than the Mft clamps.

 

[Amalix]

I looked up the demo video I saw a while back:=2m35s

Starts right about the time he shows the side clamping.

 

[Tayler_mann]

I looked up the demo video I saw a while back:=2m35s

Starts right about the time he shows the side clamping.

I see I guess for myself I really like my elements for vertically clamping. However, I do see the usefulness if you didn't have a t track on the side of your table you don't use for guide rail cutting.