Fasteners for phenolic router table

[Michael Kellough]

I’ve been storing a Rockler phenolic table for a decade and I bought the Rockler “Rock-Steady” folding stand to mount it on.
(The stand is very strong and heavier than expected with nice sticky feet. Takes about an hour to assemble.)

The stand assumes an mdf top will be used. Only 3/4” wood screws are included.
And the mounting brackets have a bunch of small holes, about #8 size (4mm).

What screws could be used with those small holes and be compatible with phenolic?

Would self tapping screws work in proper pilot holes or should I just go ahead and make four new bigger holes and use countersunk flat head bolts?

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[Packard]

Where I used to work, the tool room used to produce welding fixtures for resistance welding (spot welding).  They used phenolic sheets about 1/2” thick. 

I recall them using machine screws into tapped holes.  These were conventional machine screws with standard taps for threading. 

Of course there are many grades of phenolic and I have no idea what grade they used.  And I don’t know the holding strength that was required.

You can test in a piece of scrap. 

Amusingly, they used the phenolic because it was a non-conductor of electricity.  But electricity always flows in the path of least resistance.  So when the positive and negative welding tips are just 0.040” apart, the fixture could be made from solid copper and you still would not get shocked.

Having said all that, welders use an awesome amount of current and I would not want to hold a welding fixture made from conductive materials.  [big grin]

 

[Mini Me]

Drill & tap was my approach when I built mine. You could drill and countersink from the top and use nylock nuts underneath as an alternative method which we also did using stainless steel allen hex drive fasteners,

 

[Michael Kellough]

This phenolic is just resin, no reinforcement and softer than expected, so I went with the wood screws provided. After popping the head off the first screw I used a slightly larger pilot bit and the next dozen went in good and tight.

Looking at the screws more closely they look like course thread #6 or #7. For the pilot hole a 1/8” bit worked well enough. There isn’t much stress on the screws in this application.

The Rockler stand is very good imo and for something that folds down amazingly stable. With the 3/4” table the top of the work surface is 36-3/8”.

 

[Packard]

The phenolic that they use in our shop had layers of fabric which I think were cotton canvas.

Phenolic is a thermosetting resin, meaning that it does not melt after forming.  Plastic ashtrays are made from molded thermosetting plastics.

Phenolic can be brittle so treat it as such.

 

[Mini Me]

Phenolic must vary as mine is extremely hard almost as hard as steel, There is no way any wood screw could be driven into it, the screw would not even start.

 

[Packard]

Phenolic must vary as mine is extremely hard almost as hard as steel, There is no way any wood screw could be driven into it, the screw would not even start.

I was talking about using a drill and tap intended of metals such as aluminum or steel.  I agree a wood screw would not work, and as hard and brittle phenolic is, if you pre drilled, driving in the screw would likely crack the piece.

 

[Cheese]

I recall them using machine screws into tapped holes.  These were conventional machine screws with standard taps for threading. 

I'd also use conventional drills & taps because as Packard mentioned, it's a thermoset material...very strong but very brittle.

For conventional thermoplastic materials I really prefer using a tri-lobular screw...think Plastite®or Taptite® because it reduces the chance of breaking/cracking the material. They also have a much lower insertion force.

I don't know how rough you're going to be with the table but #8-36 screws seem to be the minimum size I'd use, 1/4-28's would make me feel better. [smile]  Then again, you could install the #8-36 screws and if they start to loosen up, you can always redrill the brackets and retap the holes for the 1/4-28 screws.

 

[Packard]

Or he can use threaded inserts designed for phenolic and conventional machine screws.  Since the screws will be causing wear on the metal inserts, the phenolic will not experience that wear.

Note that there are different inserts for different materials.  Choose the correct ones.
https://www.google.com/search?q=threaded inserts for phenolic&ie=utf-8&oe=utf-8&client=firefox-b-1-m

 

[Michael Kellough]

After I used the wood screws to install the table I discovered that Rockler had produced a document describing how to use the phenolic table on the folding stand.

They said to replace the wood screws (which actually are #8) with #8 self drilling sheet metal screws set into 1/8” holes.

Maybe the wood screws worked for me because put them in immediately after drilling while the hole was hot.
Now that everything is cool I’m not go to try to change the screws as that will likely pop the heads off.

 

[Packard]

This thread is starting to sound like a critique of phenolic.  It is hard and makes a decent bearing surface.  It is flat and will remain flat.  It will not absorb water.  It does not have any seasonal movement.

It is stronger and lighter than aluminum

Property chosen, it may very well be the ideal material for this application.

More info on properties of phenolic:
https://www.piedmontplastics.com/blog/phenolic-sheet-explained

 

[Michael Kellough]

I think phenolic is great for this purpose.

I have been storing two router tables vertically, inside, for over a decade.
One was a nice hpl laminated mdf table and the other is this phenolic table.

The mdf table has a 3/16” deep depression in the middle of its 45” length. It’s useless.
The phenolic table remains perfectly usable.

 

[Mini Me]

I am a bit puzzled after reading the link above

>Phenolics are incredibly lightweight<

The phenolic I have is 12mm thick and no way could it be termed lightweight, maybe it is not phenolic but it sure makes a good router top.

 

[Packard]

I am a bit puzzled after reading the link above

>Phenolics are incredibly lightweight<

The phenolic I have is 12mm thick and no way could it be termed lightweight, maybe it is not phenolic but it sure makes a good router top.

https://plastic-craft.com/phenolic-le-sheet/

Phenolic is a hard, dense material made by applying heat and pressure to layers of paper or fabric, impregnated with a synthetic resin. Phenolics are approx half the weight of aluminum and their physical toughness resists abrasion, friction, impact, and material fatigue. Special properties fight off the corrosive action of water and many chemicals, increasing the service life and efficiency of your product parts. The insulating qualities of each grade, such as low dissipation factor and excellent dielectric strength, make them valuable for many precise electrical and electronic applications.

 

[Mini Me]

No way is mine half the weight of aluminium and if anything it would be heavier. I am just interested in identifying what it may be if it is not phenolic because the person who gave it to me said it was Phenolic. It has a grey surface colour and is black internally and is very smooth with no pattern on the surface or internally. 

 

[Michael Kellough]

McMaster lists 15 varieties of phenolic sheet. The one I guess is used for router tables is Garolite XX. It has a black core and a 2 ft x 3 ft sheet costs about $255. It can be made with either a plastic resin core or an epoxy resin. Made with impregnated paper rather than cloth, it is consider an economical grade and good electrical insulator.

While phenolic is heavy it is certainly lighter than aluminum, whose specific gravity is identical to granite.

 

[Packard]

Or maybe G10, which uses fiberglass and epoxy cured under pressure.  I believe it is denser than phenolic.

Note:  You don’t want to breath any of the dust from any of these sheets.  Masking is a very good idea.

 

[Michael Kellough]

Or maybe G10, which uses fiberglass and epoxy cured under pressure.  I believe it is denser than phenolic.

Note:  You dont want to breath any of the dust from any of these sheets.  Masking is a very good idea.

Looking at the drilling swarf I didn’t see any sign of any other material than the resin, which seemed more plastic than epoxy, maybe.

 

[Packard]

Or maybe G10, which uses fiberglass and epoxy cured under pressure.  I believe it is denser than phenolic.

Note:  You don’t want to breath any of the dust from any of these sheets.  Masking is a very good idea.

Looking at the drilling swarf I didn’t see any sign of any other material than the resin, which seemed more plastic than epoxy, maybe.

As far as I know all phenolic has paper or fabric layers encapsulated in the resin. 

Perhaps the paper is so saturated with the resin that it becomes one with it?  The stuff we used in the shop was purchased in larger sheets and you could see the tails from the fabric on the cut edges. 

I have very little first hand knowledge about any of these. G-10 is a prized material for pistol grip sides.
https://www.lymanproducts.com/g10-tactical-grips

G-10 material is a fiberglass based epoxy resin laminate. It is an extremely tough and durable material that is impervious to moisture, weather or chemicals, making it a perfect material for handgun grips. The multiple layered construction allows the use of different colors to be added to the semi-auto grips, creating attractive patterns as it is machined. Our Pachmayr G-10 Tactical pistol grips are available in two textures, our coarse Grappler pattern or fine checkered, and two color patterns, green/black and grey/black. Pachmayr G-10 Tactical grips are the toughest, most durable, and best looking semi-auto grips on the market.

 

[Cheese]

G-10 is a prized material for pistol grip sides.

That's interesting...the only G10 I'm familiar with is the stuff used for circuit boards.

Also ran across this:
"G10 material is a high-pressure fiberglass laminate that can be used in things other than Circuit boards.  However, circuit boards are one of the more common applications. It is created by stacking multiple layers of glass cloth into a soaking epoxy resin.  It is one of the toughest glass fiber laminates out there to date. This is why it’s so popular to work with. G10 material can be used in a variety of applications such as knife handles, boating applications, printed circuit boards, Insulators, jigs and fixtures, and other components.

The material must have custom fabrication and it is not an injection molding type of material.  It is quite difficult to machine and must use specialized cutters due to the strength of the material. However, G10 can be fabricated, machined and assembled with the correct equipment and the final product is amazing."

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