Drill Speed For Countersinking Into Phenolic Sheet

[pollys1dad]

Hi all,
I've got some 3mm thick phenolic sheet to make a zero clearance insert for my tablesaw.
I'm using a single flute countersinking bit. My floor standing drill press is 550 watts and has the following speeds.
190,290,310,420,470,490,610,680,740, 765. I think is correct to use a low speed so not mentioned higher speeds, the top one is 3645.
The Ebay listing description of the phenolic sheet is, TUFNOL 1P/13 Sheet Phenolic SRBP Plastic Plate Paper laminate 1P13 electrical
Is a brown colour. What would be the best speed to use?

I also bought a sleeveless sanding drum 50mm x 75mm fitted with 120g abrasive paper.To fit on the drill to round over the corners of the phenolic sheet. Sanding drum says max 1500rpm, as you guys know a lot, what speed should I run the sanding drum to get the best finish on the phenolic corners?
OK thank you.
Peter.

[SteveHGraham]

I can't tell if you're drilling holes, but if you are, hold the work down. Plastic likes to climb up drill bits. It also likes to catch and spin.

[warmstrong1955]

I've worked with nylons, UHMW's, teflon etc, but not that stuff. Speeds must me slow to ovoid overheating.

I'd give 'em a call: http://www.tufnol.com/materials-full/pa ... -size.aspx

As far as Steve's concern of the drill bit grabbing & climbing when you drill, that can be cured with a little drill bit 'rackectomy' on the grinder.
I've not had that problem with any of the plastics I've worked with when countersinking or counterboring.

Sorry....not much help.
Bill

[pollys1dad]

I can't tell if you're drilling holes, but if you are, hold the work down. Plastic likes to climb up drill bits. It also likes to catch and spin.

OK thanks.

[pollys1dad]

I've worked with nylons, UHMW's, teflon etc, but not that stuff. Speeds must me slow to ovoid overheating.

I'd give 'em a call: http://www.tufnol.com/materials-full/pa ... -size.aspx

As far as Steve's concern of the drill bit grabbing & climbing when you drill, that can be cured with a little drill bit 'rackectomy' on the grinder.
I've not had that problem with any of the plastics I've worked with when countersinking or counterboring.

Sorry....not much help.
Bill

I didn't realize I could call them in the UK, where I am.
Will give them a call Thursday morning.
Cheers.

[Carm]

I also bought a sleeveless sanding drum 50mm x 75mm fitted with 120g abrasive paper.To fit on the drill to round over the corners of the phenolic sheet. Sanding drum says max 1500rpm, as you guys know a lot, what speed should I run the sanding drum to get the best finish on the phenolic corners?

Run the drum at low RPM, enough to get a bite. Tufnol acts more like wood than plastic and will burn at higher speeds. Assuming the work is clamped, a drill won't grab for the size you're using.
A single flute c'sink will give better results.
A respirator or good draught recommended. (I think that's how you spell "draft")

[Harold_V]

(I think that's how you spell "draft")

Depends. It's a "regional" thing.
Here in he US, draft is a breeze, or to draw (a line, for example).
Draught is to do with pouring a fluid, like a draught beer, also pronounced draft.

I think (I'm not sure I'm right) that the Brits use the draught spelling for all situations.

Harold

[Lew Hartswick]

I just did one 5/16 Flat head and 2, 10-32 flat head c-sinks today in linen filled phenolic on the mill
today. I used a multi flute csink to have more cutting edges in contact at a time. I just left the
spindle at the same speed I had been using to drill and mill the edges 1150 rpm and fed the
cutter in small increments with a lift/pause after half sec. or so contact. Had to have the heads flush
or slightly recessed.
...lew...

[pollys1dad]

OK thanks everyone for your input.
Peter.

[Magicniner]

(I think that's how you spell "draft")

Depends. It's a "regional" thing.
Here in he US, draft is a breeze, or to draw (a line, for example).
Draught is to do with pouring a fluid, like a draught beer, also pronounced draft.

I think (I'm not sure I'm right) that the Brits use the draught spelling for all situations.

Harold

Here you go, English as she is meant to be spoke -

http://www.oxforddictionaries.com/defin ... lish/draft



- Nick

[SteveHGraham]

Run the drum at low RPM, enough to get a bite. Tufnol acts more like wood than plastic and will burn at higher speeds. Assuming the work is clamped, a drill won't grab for the size you're using.

Table saw inserts typically have finger holes maybe 7/8" in diameter. You better believe a drill bit that big will grab, and a hole that big will definitely provide enough grip to make the work ride up the bit.

I managed to punch myself in the face with a drill handle this week. Grabbed in mahogany. I feel good about my decision to never film anything I do with tools.

[tornitore45]

When drilling Printed Circuit Board in Phenolic or Fiberglass at very high RPM the bit heats up, but high RPM is necessary with small bits to reach the proper cutting speed in FTM.
I saw the manufacture use a thin aluminum sheet under the piece and drill into it to cool the bit.
Whether this techniques applies to what you are doing, I can't say.