MFT Top

Birdhunter

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Jun 16, 2012
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I have a pair of MFTs. Both suffer from "sag". I have flipped the tops but this seems to be a poor solution.

Anything better on the market?
 
Attach a stiffening beam either screwed directly to underneath the plate, or to MFT frame. The frame conveniently has t-slots on the inside. It will interfere with clamping a bit.
 
This is my experience with MDF for what it’s worth. I have a 4’x8’ cnc router table with a vacuum table that I use a ¾” MDF sheet as a spoil board. The unit is in an air-conditioned environment and my spoil board was continually bowing up on the corners – even more so whenever I would surface the top to renew it. Since I’m in southwest Louisiana, I contributed my problem to the climate. I was buying the product from a local home center and since I’m not in a production shop, I didn’t have to change the sheet very often. All of the sheets that I had put on it had the same bowing characteristics to the point that when I turned on the vacuum, I had to go around and physically push the corners down.

I scoured the internet for a solution, but as you already know what worked for one person didn’t work for the next. I made up my mind that I was going to find a supplier with light weight MDF and I did. I went over to pick it up and the sheets weren’t in good shape at all. They had a lot of warehouse wear. I told the person what I was doing and the problems that I had. He suggested that I buy a sheet of Plum Creek MDF and I did. Now my spoil board is absolutely flat with zero bowing.

I know that my sheet is fully supported and is not in an installation like the MFT table top. I will be machining an MFT style top in the next two to three weeks. I know that it should take some time for sagging to show up so I won’t be able to report back any time soon. I really wonder if the material grade will make a difference.

 
Festool make a phenolic-faced ply top for the MFT, but they only use it for their roadshows; they are not for sale.

Ply is much stiffer than MDF and therefore will sag much less.  I have exactly the same problem as you and am thinking of getting some ply and making my own.  Ideally I'd like it in hardwood (baltic birch?) ply with a phenolic laminate on both faces.

Axminster sell tops made from Valchromat:http://www.axminster.co.uk/ujk-technology-hdf-valchromat-top-for-parf-dogs-102537
but I'm not sure they'd be any better than MDF.  Certainly the specs suggest it's no stiffer than MDF; it just looks nicer!

If anyone knows better please correct me.

Andrew
 
Hi Roseland.  I would expect the HDF (High Density Fibreboard) Axminister use, to be be far superior to MDF. 

Google MDF vs HDF - then take your pick.  Lots of good info' out there. 

As an aside: have you ever been involved with commercial HDF office furniture - heavy, very heavy; and, doesn't want to twist, bend or anything!

Richard (UK) 
 
Richard,

You're absolutely right, HDF is stiffer than MDF, but I think the standard MFT tops are actually HDF, and they still sag.  Valchromat is coloured HDF, unless I'm mistaken.  Ply is still stiffer and less prone to sag.

I'm only slightly familiar with HDF outside of MFT tops and, yes, it's very heavy!

A
 
HDF is not so easy to get hold of these days, partly because it is so expensive but there are cheaper products around which have similar engineering properties.

I use Medite MR for all my track saw cutting stations and I have made several replacement MFT3 tops with it. It drills cleanly (with the special PGS 20 mm cutter), is moisture resistant and I have not experienced any deformation in an MFT3 size top.

Peter
 
For those in the US Anderson Plywood has a good selection of phenolic plywood.
I have thought of ordering from them but being all the way across the country shipping would probably be a killer. I have not contacted them yet to inquire about shipping. Unfortunately I have not found anyone with as wide a selection locally. I know there are others who do sell and ship nationally.

I believe Anderson has a presence here and hopefully they will weigh in on the shipping question and maybe provide information on shipping a half sheet (4x4) and a full sheet cut into two 4x4 pieces. A full sheet cut in half would give enough for two MFT tops plus some bits that would be useful for jigs and such, or one MFT top and a half sheet for whatever.
https://www.andersonplywood.com/284/phenolic-plywood/

You may be able to get a sheet of phenolic ply used for concrete forms at your local lumber yard. I believe it's also available one inch thick. But, because its intended use is concrete formwork it's not always handled with respect and may have surface imperfections/blemishes that mean nothing for concrete work but would not be acceptable for other uses.
 
Bob D. said:
For those in the US Anderson Plywood has a good selection of phenolic plywood.
I have thought of ordering from them but being all the way across the country shipping would probably be a killer. I have not contacted them yet to inquire about shipping. Unfortunately I have not found anyone with as wide a selection locally. I know there are others who do sell and ship nationally.

The local Menards stores sell 18mm thick black colored phenolic plywood, it's called Tiger FORM. A 4' x 8' sheet runs $50. I haven't tried or used it, just saw it when I was picking up some maple ply.
 
Hi I am Don I work at and handle the Festool at Anderson Plywood.
We have Phenolic ply. It's on a Baltic Birch core.
We make the MFT squares out of it.
We tried making MFT tops out of it but the phenolic is very slick.
And it was hard to keep things from moving ..........
It Looked cool but ............ Not sure if phenolic is the right stuff .
 
The local Menards stores sell 18mm thick black colored phenolic plywood, it's called Tiger FORM. A 4' x 8' sheet runs $50. I haven't tried or used it, just saw it when I was picking up some maple ply.
[/quote]

What is the quality like on the maple plywood from Menards?  I am looking at it for a winter project.
 
Roseland said:
I think the standard MFT tops are actually HDF, and they still sag. 
No, MFT tops are regular MDF. There was a discussion on this before and someone posted an official response from Festool stating that MFT tops are made of MDF, and not HDF. You could easily weigh your top and calculate the density yourself. Whether MDF in Germany is different from MDF from a hardware store in the US is another question.
 
TacoTraveler said:
What is the quality like on the maple plywood from Menards?  I am looking at it for a winter project.

Not bad, there are some issues however. The veneer is thin .016"-.018" (1/64"), you have to check the ply thoroughly for the veneer chipping on the edges of the ply and usually on one side, there are a lot of dark mineral stains while the opposite side is relatively stain free.

In my case, the cabinets will be placed inside of an upstairs knee wall so they will be completely hidden. The front of the cabinets will all be solid maple, so this ply works for me especially at $50 per sheet and on sale it's only $44 per sheet.

The photo below shows one side of the cabinet with 3 coats of water based clear...just to give you an idea.

The second photo gives you an idea of the mineral stains I was referring to. Just look at the side of the fake mini drawer I made.
 

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[member=44099]Cheese[/member] , I'm curious what is that on the pictures? Some robotic sliding table?
 
Svar said:
[member=44099]Cheese[/member] , I'm curious what is that on the pictures? Some robotic sliding table?

Just some Blum slides fitted with reed switches that will control LED lighting for each drawer. Waiting for the LEDs to arrive so I can dry assemble everything and then do the final assembly of the whole cabinet and tidy up the wiring. If everything works/fits as it should, then I'll fabricate 3 more cabinets and join them altogether. Should give me 10 feet of storage for the loft.

 
A great thread, with some useful information.  And thank you Don, for saving me the cost and work in making a phenolic-faced top!

Ply, which has a flex modulus of 10,000 N/mm2 (http://www.wisaplywood.com/Products/product-catalogue/wisa-birch/Pages/Default.aspx) looks the stiffest, Peter's Medite looks the next best, with a modulus of 3,790 N/mm2 (http://www.hardwoodweb.com/architectural/docs/MediteIISpecJul09.pdf).

MDF seems very variable, from 1,500 - 3,200 N/mm, depending on the glue used (http://www.decospan.com/media/files/en-decospan-decopanel-2.pdf).

Valchromat is up there with the best of the MDF family, at 3,100 N/mm2 (http://www.lathamtimber.co.uk/upload/files/EN_Valchromat_Product%20Data%20Sheet_13.pdf)

So what's wrong with a nice birch ply top?

Andrew
 
I think that a major consideration is the expected life of the top. Some may want to protect their bench tops but many of us use them and abuse them.

With Medite MR the cost is low enough that one just does not need to worry about any damage at all. Other materials may leave the owner a little nervous about doing woodwork !

One of the key things about this is the ability to reproduce the next generation bench top once the old one is too beaten up. That is one of the key USPs of the Parf Guide System. I am sorry to plonk a direct plug in like this but bench tops are at the forefront of the woodworking effort and the ability to replace an old top quickly with superb accuracy is quite important.

Peter
 
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