MFT table top type of work - custom

[Frankie Hunt]

There are a few jigs out there that help you drill or rout those holes. I thought Woodpeckers had one but I couldn't find it on their site.
Good luck.

The woodpeckers kit was a "one time tool" offering.

https://www.woodpeck.com/hole-boring-jig.html

[Bob Vallaster]

Laura, thanks for raising this topic. I want to do a similar project.

To Frank and Brian, the Woodpeckers one-time-tool deadline passed in November; deliveries to commence in February. Made me think, "no harm in asking...". I just visited the link above (works dandy), called them, and placed an order.

I'm a happy camper.

BobV

[laura vianello]

That is great! What is the new dead line? Which items did you buy? Why did you feel that it was better than Parf system? Do you have Veritas benchdog? Tx

[Ben Abate]

I would suggest going over to the FOG Festool site and do a search. There is a lengthy discussion on how to do it your self with CNC accuracy. Peter Parniff from the UK along with Axminster Tools offer a set up that has gotten great reviews.

I went the CNC route and had a fellow I knew make my top. It took a few times for him to get it to my specs. A lot of time and money. If you go the CNC route find a reputable person and find out who pays for the mistakes. Also there will most likely be a setup and a charge for doing the programming. Some things you may have not thought of

take care

[Ted Derryberry]

Another thing about CNC is the operator might be tempted to use a smaller bit and "cut out a circle" rather than "drill a hole" if they don't already have a 20mm bit. Unless the machine and bit are very stiff you're going to end up with a tapered hole. I tried this on my CNC table and had to go back with a drill bit and chase all of them. I bought a full size bit for the next time I do it, once I get everything squared up.

Programming charges for this project should be minimal. I could set up the file in about five minutes from opening the program to ready to cut.

[laura vianello]

Is it an offer? I do not have a CNC.

[Victor Robinson]

Of all the methods, the UJK Parf guide (that Lee Valley as well as TSO Products sell in the US) is probably the best combination of accuracy and price. It costs about as much as having one top made by a competent CNC operator, but you'll be able to make as many tops as you need. It's also the most labor-intensive since you're drilling (not even routing) each hole yourself.

The Woodrave jig is fine (I have it also) but you're dependent on the quality of the pegboard you source so if you're looking for absolute accuracy you might be disappointed.

[laura vianello]

Yes, I love the Parf System. I am currently evaluating if I need a corded drill though. My 2 cordless are not going to to make it. Do you think I need a corded?

[Hoang N Nguyen]

I made a big MFT style table, 3'x6' and use it as an assembly table and outfeed table. Works great and love it. I'm lucky enough where the company I work for has a 20' CNC router and I was able to throw an entire sheet of MDF on it to have it cut.

If you do find a company to CNC the top for you, I would suggest having more than one cut and just saving it for later. This will increase the amount of machining time as well as cost, but would also entice the company to take on the job and save you money down the road when it comes time to replace. I use my table to make cuts with using my TS55 track saw so there's a lot of cut lines in it. Over time, stains, paints and glue gets on it as well and will need replacing.

[Brad Shipton]

Cutting out these holes on a CNC is not that complicated, but I do agree you need to add a tolerance spec to the diameter callout for circles on your drawing. The tolerance should read 20mm -0.000" / +0.010" (assuming the exact diameter of the MFT dogs is 20mm). If you put a spec like that on the drawing and they ask what that is, go to someone else. Anyone with Biesse, CR Onsrud, Thermwood or another of the industrial machines can produce a ridiculously simple piece like this to a tolerance of 0.005". If you need better than that you are working with the wrong media. If you start talking to someone with a hobby machine you will need to make sure they understand the capability of their machine. I could produce this on my 4'x8' machine to within 0.010", but that takes time and the interest in setting up your machine to do so when you buy an entry level machine (grid squares in image below all within 0.010" so I can use vacuum pods).

I think Ted means an oblong hole. That will be largely the result of a sloppy operator that never checks the X/Y accuracy of his machine. So long as they use a 3/8" diameter bit, and the machine is not a cheap pile, using a pocket tool path is fine. If you spec that you want them to use a special bit they do not own, they will charge for that. A 20mm bit will be in the realm of $100 and they may need a $30 collet as well. Keep in mind you will be begging for someone to do this. Someone that owns a $100k machine could care less about your $100. The less annoying you are the more likely they will do it.

If you could live with a reduction in the length that will make the operators setup a bit quicker. To utilize the full 60" length without much extra setup time they would need popup pins. Most cab shops have that, but some of the smaller machines do not. Also, you can probably get two for very little cost. If it were me, I would charge you for the full sheet of Baltic Birch unless I had a piece kicking around.

Shipton_CNC-Table-exx.jpg

[Ted Derryberry]

I actually meant a tapered hole that is tighter at the bottom than it is at the top. My machine isn't so out of square that a 3/4" diameter hole is noticeably oblong! I don't even start to notice anything being oblong until I get to a 24" diameter circle and then it's within "sanding tolerances".

I was "drilling" using 1/2" bit on a spiral ramp to create a 3/4" hole through 1" MDF and 3/4" cabinet birch plywood. By the time it got through the bottom of the plywood the machine/router motor (not a spindle)/bit were flexing enough that it was trying to stay in the center of the hole. I couldn't get any of my dog clamps to fit and had to chase all the holes with a forstner bit. Now I know better and have a long 3/4" bit. Someone with less experience might be tempted to try the same thing in lieu of buying a 20mm bit, which I suspect is a little harder to find and more expensive than a 3/4".

In short there are two issues that could easily come up with a hobby machine and/or inexperienced operator. Out of square pattern and out of spec holes.

I agree the biggest issue is going to be finding someone with the proper machine that cares about a small job. The guy willing to take on the small job is less likely to have the machine capable of doing it well and the guy with the right machine can't be bothered. I'd probably go with one of the jig systems myself or make my own jig with very careful layout.

[Brad Shipton]

That is interesting Ted. I have never had tapered holes, but I did have some oblong holes long ago when I did not always check my tolerances as carefully. I did a small project a few years back for someone where the a lot of dowels had to fit into holes, but the holes had to be quite reasonable so the dowels would not fall over. I nearly lost my mind, but I learned a lot about my machine. Small circular pockets are not the best on smaller machines. When I crank up the cut speed I can feel my machine vibrate back and forth a little bit and my machine still weighs 2600lb. There is a reason the industrial machines tend to weigh in around the 6,000lb+ mark.

[Jim Becker]

Cutting out these holes on a CNC is not that complicated, but I do agree you need to add a tolerance spec to the diameter callout for circles on your drawing. The tolerance should read 20mm -0.000" / +0.010" (assuming the exact diameter of the MFT dogs is 20mm).

The dogs for 20mm holes are typically 19.95-19.98mm. They can't be exactly 20mm or they'd be unusable. But that backs up your +/- specification. Smaller than 20mm is absolutely no-good. "Slightly" large by a tenth of a mm will likely be ok. CNC tool paths also have to be stepped enough to maintain tolerance at this depth of cut so there's no taper from excess lateral pressure on the cutter.

[John Stankus]

On the Alpharetta Georgia craigslist there is a shop that is making these
Also there is a guy selling cad drawings for multifunction slab mfs (google it) so you can get you local CnC shop.
There are replacement mft tops and lee valley has something though it looks smaller
Dominofix has a jig to make your own

Google is your friend

[Brad Shipton]

Thanks Jim. I had never measured my MFT hold downs, so that is why I assumed the size. Industrial CNC machines drive 3/8" and 1/2" diameter bits at 1000 - 2000ipm in many different woods cutting irregular shapes where you would see taper if you bit deflection were a problem. That is the reason they need 25 - 40hp vacuums for stock hold down. The head cannot accelerate to speeds anywhere near that speed for such small holes, so I highly doubt taper would be an issue with a reasonable machine.