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'[EE] Cutting holes in thick uPVC pipe caps'
2011\02\10@210609 by Philip Pemberton

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(EE because "making stuff" is part of engineering :P )

This has been annoying me since about 8PM.

I'm building a case for the night-vision tube using a couple of lengths of PVC pipe. One 90mm dia. length holds the tube proper, and a 50mm-dia. length serves as a spacer to keep the focal-plane distance (distance from the lens to the input coupler) correct. There's a 90mm pipe cap on either end -- one to hold the eyepiece, the other to hold the lens mount and spacer.

What I need to do is knock a ~45mm hole in the front of one of the pipe caps.

Problem 1: these are EXTREMELY thick pipe caps. The plastic walls are about 15mm thick!

Problem 2: I don't have a hole-saw suitable for PVC (actually, I don't have a hole-saw at all: the one in the toolbox has a broken setscrew so the drill bit won't pass any motion onto the saw-blade).

I've tried using the hot-knife bit on an Antex GasCat, which sort-of worked... apart from the fact that it filled my kitchen with acrid smoke and I had to give up part-way through. Turning the heat down only served to completely stop the PVC from melting. Lovely.

The Dremel won't work either -- the router bit gets clogged with bits of PVC very, VERY quickly and just plain stops cutting. I suspect my PCB router bit isn't geared up for uPVC, or the Dremel is moving too fast and melting the plastic (not surprising).

Short of "buy a new holesaw" (apparently *not* stocked by the local B&Q), does anyone have any ideas how I might be able to cut these holes?

Thanks,
-- Phil.
spam_OUTpiclistTakeThisOuTspamphilpem.me.uk
http://www.philpem.me.uk

2011\02\10@212208 by doug metzler

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maybe a stepped drill bit?

http://www.amazon.com/Neiko-Titanium-Step-Drill-Bit/dp/B000FZ2UOY

It might not solve your 15mm thick problem, though, but it'll do a great job
going through the material.

That said maybe you could use it in some ingenious manner to not only drill
the hole but also step-drill a shelf against which the lens can sit.

DougM

On Thu, Feb 10, 2011 at 6:06 PM, Philip Pemberton <.....piclistKILLspamspam@spam@philpem.me.uk>wrote:

{Quote hidden}

>

2011\02\10@213001 by Mark Rages

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On Thu, Feb 10, 2011 at 8:06 PM, Philip Pemberton <.....piclistKILLspamspam.....philpem.me.uk> wrote:
> (EE because "making stuff" is part of engineering :P )
> Short of "buy a new holesaw" (apparently *not* stocked by the local
> B&Q), does anyone have any ideas how I might be able to cut these holes?
>

http://www.mini-lathe.com

PVC cuts like butter in a lathe.

Regards,
Mark
-- Mark Rages, Engineer
Midwest Telecine LLC
EraseMEmarkragesspam_OUTspamTakeThisOuTmidwesttelecine.co

2011\02\10@213800 by IVP

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> Problem 1: these are EXTREMELY thick pipe caps. The plastic
> walls are about 15mm thick!

Can you cut it down to 5mm with a hacksaw

2011\02\10@214123 by Marc Nicholas

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Sent from my iPhone
416.414.6271

On 2011-02-10, at 9:22 PM, doug metzler <doug.metzlerspamspam_OUTgmail.com> wrote:

> maybe a stepped drill bit?
>
> www.amazon.com/Neiko-Titanium-Step-Drill-Bit/dp/B000FZ2UOY
>
I bought one of those to cut holes in a 55 gal steel drum. Worked like a champ!

-mar

2011\02\10@214228 by Matt Callow

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On 11 February 2011 13:06, Philip Pemberton <@spam@piclistKILLspamspamphilpem.me.uk> wrote:
{Quote hidden}

How about chain-drilling the hole, then finishing off with a sharp knife?

Mat

2011\02\10@214912 by PICdude

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- You can use the dremel, but keep it well lubricated -- have someone  spray WD-40 on it while you route.

- Get a hole saw (or next smaller size), and cut it, while keeping it  lubricated (as above).

- Lathe.

- CNC mill.

FWIW, making stuff is engineering, but not *electrical* engineering.

Cheers,
-Neil.



Quoting Philip Pemberton <KILLspampiclistKILLspamspamphilpem.me.uk>:

{Quote hidden}

>

2011\02\10@223811 by Bob Blick

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On Fri, 11 Feb 2011 02:06 +0000, "Philip Pemberton"  wrote:
> (EE because "making stuff" is part of engineering :P )

Yes! Someone who gets it!

> Short of "buy a new holesaw" (apparently *not* stocked by the local
> B&Q), does anyone have any ideas how I might be able to cut these holes?

Immerse it in a pail of water to keep it cool and then use your dremel
or drill multiple holes in it.

Cheerful regards,

Bob

P.S. don't electrocute yourself in the process!

-- http://www.fastmail.fm - One of many happy users:
 http://www.fastmail.fm/docs/quotes.html

2011\02\10@230730 by jim

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How about buy a large diameter auger bit or spade bit?

Jim

-----Original Message-----
From: spamBeGonepiclist-bouncesspamBeGonespammit.edu [TakeThisOuTpiclist-bouncesEraseMEspamspam_OUTmit.edu] On Behalf Of
Bob Blick
Sent: Thursday, February 10, 2011 9:38 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Cutting holes in thick uPVC pipe caps

On Fri, 11 Feb 2011 02:06 +0000, "Philip Pemberton"  wrote:
> (EE because "making stuff" is part of engineering :P )

Yes! Someone who gets it!

> Short of "buy a new holesaw" (apparently *not* stocked by the local
> B&Q), does anyone have any ideas how I might be able to cut these holes?

Immerse it in a pail of water to keep it cool and then use your dremel
or drill multiple holes in it.

Cheerful regards,

Bob

P.S. don't electrocute yourself in the process!

-- http://www.fastmail.fm - One of many happy users:
 http://www.fastmail.fm/docs/quotes.html

2011\02\10@230842 by Josh Koffman

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On Thu, Feb 10, 2011 at 10:38 PM, Bob Blick <RemoveMEbobblickspamTakeThisOuTftml.net> wrote:
> Immerse it in a pail of water to keep it cool and then use your dremel
> or drill multiple holes in it.

My machinist often puts certain plastics in the freezer before
engraving or cutting them.

Josh
-- A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.
        -Douglas Adams

2011\02\11@030102 by Picbits Sales

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Do you not have a Screwfix near you Philip ?

Its a bit expensive at £40 but its infinitely variable and even clears up after itself ;-)

http://www.screwfix.com/prods/48984/

Dom

{Original Message removed}

2011\02\11@044419 by Philip Pemberton

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On 11/02/11 02:49, PICdude wrote:
> FWIW, making stuff is engineering, but not *electrical* engineering.

And the [EE] tag means "Everything Engineering", not "Electrical Engineering"...

http://www.piclist.com says:
  [EE]: This label is for topics that, while not necessarily about PICs, are of general interest to the engineering community.

Although maybe [TECH] might have been a better choice...

-- Phil.
piclistEraseMEspam.....philpem.me.uk
http://www.philpem.me.uk

2011\02\11@045730 by IVP

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> Although maybe [TECH] might have been a better choice...

[TECH] is for stuff you can't do at hom

2011\02\11@065322 by RussellMc

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> > Although maybe [TECH] might have been a better choice...
>
> [TECH] is for stuff you can't do at home

But, he's asking about it BECAUSE he hasn't been able to do it at home ... ;-)

2011\02\11@075543 by Justin Richards

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That is thick plastic.

My 2 cents ...

Jigsaw

Lots of drill holes drilled close together in a circle.

Drill a large hole for a hacksw blade then re-assemble blade into
hacksaw while located in hole drilled in cap.

Fret saw similar to above.

borrow a hydraulic hole punch, these are great fun

Sharpen a socket with angle grinder/bench grinder then use as a punch
with the aid of a vice and a larger socket.  I have often used the
vice with home made punches to press thru thick material.  Have often
used stanley blades to cleanly knife thru thick material with the aid
of a vice.

Chisel and hammer. Might fracture the plastic.
>
> What I need to do is knock a ~45mm hole in the front of one of the pipe
> caps.
>
> Problem 1: these are EXTREMELY thick pipe caps. The plastic walls are
> about 15mm thick

2011\02\11@075735 by John Chung

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Use a drill first. Drill all the way. Then use a round file
to file out the plastic into circle.... Not pretty but it will work
well. You will need a round file and half round ring file.

John



--- On Fri, 2/11/11, Philip Pemberton <EraseMEpiclistspamphilpem.me.uk> wrote:

{Quote hidden}

> -

2011\02\11@075747 by Justin Richards

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Below may be refereed to as chain-drilling which was previously
offered as an option
>
> Lots of drill holes drilled close together in a circle.

2011\02\11@084047 by Dave Lagzdin

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Melting sounds like a feed rate issue, did you slow down the dremel?

Alternately the outrigger style cutters( as Dom suggested)  in a drill
press set very slow should work
www.acehardware.com/product/index.jsp?productId=1333354
D

On 11 February 2011 03:00, Picbits Sales <EraseMEsalesspamspamspamBeGonepicbits.co.uk> wrote:
> Do you not have a Screwfix near you Philip ?
> Its a bit expensive at £40 but its infinitely variable and even clears up
> after itself ;-)
> http://www.screwfix.com/prods/48984/
> Dom

2011\02\11@084921 by Carl Denk

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First I would suggest a hole saw, they are inexpensive,  don't require a huge drill to drive it, make a fairly neat hole, and are available in 1/16" (1.6 mm) increments.
2nd, a hand held jigsaw with a blade that is thin enough to allow tight radius cuts.

Both of these are very common, if can't buy, rental or borrowing should be a possibility.

No matter which method, drill briefly and allow material and cutter to cool, and if possible a coolant. If the material melts, a rougher hole happens, and possible to seize tool in hole.

3rd, with dremel, use a 1/8" dia. cutter used to cut wood and drywall like Dremel #560, 561, or Rotozip cutters. Here again material needs to be kept cool. A template that the chuck or smooth part of bit rides on will be helpful, these bits like to wander.

If drilling multiple holes in a circle, start with smaller pilot holes, then using progressively larger bits, say start with 1/8" and stop at 1/4". In plastic, if the drill gets near an adjacent hole, it might try to walk into the next hole, then it gets messy.

On 2/10/2011 11:08 PM, Josh Koffman wrote:
> On Thu, Feb 10, 2011 at 10:38 PM, Bob Blick<RemoveMEbobblickKILLspamspamftml.net>  wrote:
>    
>> Immerse it in a pail of water to keep it cool and then use your dremel
>> or drill multiple holes in it.
>>      
> My machinist often puts certain plastics in the freezer before
> engraving or cutting them.
>
> Josh
>

2011\02\11@090544 by Carl Denk

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Spade might (slight chance) work, but I don't think an auger will. Both of these have fly cutters that score the perimeter, and then with a hand plane (wood) or chisel action, shear the fibers. The plastic doesn't doesn't have the fiber structure. Neither of these will cut decently on end grain wood. Try a wood chisel, to shave off thin slices of the plastic, difficult.

On 2/10/2011 11:07 PM, jim wrote:
> How about buy a large diameter auger bit or spade bit?
>
> Jim
>
> {Original Message removed}

2011\02\11@091842 by Carl Denk

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On 2/10/2011 9:06 PM, Philip Pemberton wrote:
> (
>
> Problem 2: I don't have a hole-saw suitable for PVC (actually, I don't
> have a hole-saw at all: the one in the toolbox has a broken setscrew so
> the drill bit won't pass any motion onto the saw-blade).
>    The hole saw shank should be chucked in the drill, not the drill itself, but to use the drill, grind a flat on the drill for the set screw to clamp on.
>
> The Dremel won't work either -- the router bit gets clogged with bits of
> PVC very, VERY quickly and just plain stops cutting. I suspect my PCB
> router bit isn't geared up for uPVC, or the Dremel is moving too fast
> and melting the plastic (not surprising).
>    Wrong bit, one I suggested has about 1.5" cutting length, the flutes (grooves) are sharpened, and the spiral ejects chips. Try lower speed, maybe using 1/4" electric drill. Speed will melt plastic, and make a mess.
> Short of "buy a new holesaw" (apparently *not* stocked by the local
> B&Q), does anyone have any ideas how I might be able to cut these holes?
>    Borrow, or maybe even pay someone to make the hole. With right tools, it's a 10 minute job. Otherwise could be hours and not a neat job.
> Thanks,
>

2011\02\11@103757 by PICdude

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Quoting Carl Denk <cdenkSTOPspamspamspam_OUTwindstream.net>:

>> The Dremel won't work either -- the router bit gets clogged with bits of
>> PVC very, VERY quickly and just plain stops cutting. I suspect my PCB
>> router bit isn't geared up for uPVC, or the Dremel is moving too fast
>> and melting the plastic (not surprising).
>>
> Wrong bit, one I suggested has about 1.5" cutting length, the flutes
> (grooves) are sharpened, and the spiral ejects chips. Try lower speed,
> maybe using 1/4" electric drill. Speed will melt plastic, and make a mess..


Will have to disagree with this.  Cutting at almost any speed will  generate enough heat to melt the plastic, as the bit lingers in the  just-cut area.  The way to not melt the plastic is to move out of the  area just cut as quickly as possible, so that means faster feed rate.   And that means faster spindle speed.  Yes, that also means greater  side load on the spindle bearings, so the way to compensate for that  is to take shallower cuts... ie: cut a few mm deep very quickly, then  go around the same path again, but another few mm deep, etc.  This is  fairly standard milling procedure.

If you can make a wooden (or other) template for the spindle  guard-ring to ride on, so it follows the circle, this will make the  whole process MUCH easier.  And keep it cool with WD-40 also.

FWIW, you may want to cut the circle a bit smaller, then file or use a  sanding drum to open it up slowly to the perfect shape/size.

Or if all that fails, just send it to me and I'll CNC-mill it for you.

Cheers,
-Neil.


2011\02\11@111207 by Philip Pemberton

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On 11/02/11 13:49, Carl Denk wrote:
> First I would suggest a hole saw, they are inexpensive,  don't require a
> huge drill to drive it, make a fairly neat hole, and are available in
> 1/16" (1.6 mm) increments.

Well, I picked up two hole-saw kits -- a £10 one from Maplin, and a £15 one from B&Q.

The B&Q one is exactly the same as the "monkey-metal" one I rubbished earlier: a setscrew holding a drill bit in the middle of a metal holder. It sort-of works, but if the saw blade locks up while the drill bit continues spinning, it might (probably will) damage the drill bit.

The Maplin one is a little nicer. The saw blades are solid units -- you pick a blade, attach it to the drill bit via a mounting block, which uses an Allen bolt to hold the drill bit in place. The coupler (which goes into the drill chuck) has a few flat edges, apparently to make it easier for a 3-jaw chuck to grip. Similar idea, but the drill bit is more likely to stick in this case -- but even so, once the drill bit is through, it's not a big deal.

Unfortunately my POS cordless drill decided to play silly devils. The battery won't hold a charge, and because it's a noname POS, you can't get replacements. That'll teach me to buy no-name kit...

Solution: another new toy. A Bosch PSR 18 LI-2. Feels like it was built to hammer nails, fast charge battery, and apparently you can buy everything from case components to the motor, gearbox, switches and the even the speed controller module as a spare part...
Wish I'd bought it from Amazon (about £60 cheaper than B&Q) but I wanted it today, and paid the price... It's still worth £160, IMO.

> No matter which method, drill briefly and allow material and cutter to
> cool, and if possible a coolant. If the material melts, a rougher hole
> happens, and possible to seize tool in hole.

That's pretty much par for the course when cutting/drilling any type of plastic. "Go slowly!"

I still ended up using a set of files to clean up the hole (and the Dremel to cut off a few bits for the lens mount), but it went pretty well. Just need to give the plastic a good clean and apply a bit of black Milliput putty to get rid of a few light leaks.

> 3rd, with dremel, use a 1/8" dia. cutter used to cut wood and drywall
> like Dremel #560, 561, or Rotozip cutters.

I went looking for the Dremel round-cutter while I was at B&Q -- but not a Dremel tool to be seen. Spent a good 15-20 minutes perusing the "electric tools" aisle, to no avail.

> Here again material needs to
> be kept cool. A template that the chuck or smooth part of bit rides on
> will be helpful, these bits like to wander.

In my experience all drill bits like to wander unless you're using a drill press...

Plasterboard bits can usually be persuaded into running straight using a bit of masking tape arranged in an "X" over the desired location, and a small hole (made with a bradawl) in the middle. An automatic centre punch works great on aluminium and other soft metals. It's been a while since I've tried the masking-tape trick on plastic, though IIRC it didn't work too well.

> If drilling multiple holes in a circle, start with smaller pilot holes,
> then using progressively larger bits, say start with 1/8" and stop at
> 1/4". In plastic, if the drill gets near an adjacent hole, it might try
> to walk into the next hole, then it gets messy.

And yet... I didn't think of that. A bunch of 3mm holes joined up with a carbide router bit would have worked pretty well...

(... and it's at this point I start re-reading the "panel building" section of Steve Kasten's book, and all the old EPE "Techniques: Actually Doing It!" columns by R. A. Penfold...)

-- Phil.
spamBeGonepiclistSTOPspamspamEraseMEphilpem.me.uk
http://www.philpem.me.uk/

2011\02\11@114318 by Carl Denk

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On 2/11/2011 11:12 AM, Philip Pemberton wrote:
{Quote hidden}

http://www.rotozip.com/en-us/Pages/CategoryDetail.aspx?pid=9_8#

{Quote hidden}

>

2011\02\11@115018 by Bob Blick

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On Fri, 11 Feb 2011 09:44 +0000, "Philip Pemberton" wrote:
> On 11/02/11 02:49, PICdude wrote:
> > FWIW, making stuff is engineering, but not *electrical* engineering.
>
> And the [EE] tag means "Everything Engineering", not "Electrical
> Engineering"...
>
> http://www.piclist.com says:
>    [EE]: This label is for topics that, while not necessarily about
> PICs, are of general interest to the engineering community.
>
> Although maybe [TECH] might have been a better choice...

Hi Phil,

piclist.com does not have the official description. The subscription
page has the real one:
http://mailman.mit.edu/mailman/listinfo/piclist

The [EE] topic tag is basically for engineering that you can do
yourself. There is some blend into [TECH] depending on the type of
engineering. In this case it is engineering that someone doing EE is
likely to do at some point, so it fits fine in either EE or TECH.

Cheerful regards,

Bob

-- http://www.fastmail.fm - Choose from over 50 domains or use your own

2011\02\11@115202 by Carl Denk

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On 2/11/2011 10:37 AM, PICdude wrote:
{Quote hidden}

>

2011\02\11@121612 by Philip Pemberton

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On 11/02/11 16:43, Carl Denk wrote:
>> The B&Q one is exactly the same as the "monkey-metal" one I rubbished
>> earlier: a setscrew holding a drill bit in the middle of a metal holder.
>> It sort-of works, but if the saw blade locks up while the drill bit
>> continues spinning, it might (probably will) damage the drill bit.
>>
> Gripping the drill bit, and relying on the bit to turn the hole saw, is
> only for very light work at best.

As I found out... The drill bit tended to slip in the chuck (it's covered in silver marks where the chuck jaws have spun around the bit). Hopefully it didn't damage the chuck...

> Yep that's what the flats are for, the quality drill bits, larger than
> 3/16" that I buy at the local independent tool store, all have the
> flats.

It's pretty rare to see drill bits with a flattened shank around here. The vast majority are round -- even the PCB drills.

> I always buy name brand that there are local repair stations for parts.
> Long term well worth it. A lot better than at most inopportune time,
> having to go chase tools.

Oh, too right. Before I got the Dremel, I used to drill PCBs with an Expo Reliant "mini-drill". That was an exercise in futility. The 3-jaw chuck wasn't mounted straight on the motor shaft, so the bit moved to either side. Broke most of my tungsten bits before I figured out what was going on.

>> Wish I'd bought it from Amazon (about £60 cheaper than B&Q) but I wanted
>> it today, and paid the price... It's still worth £160, IMO.
>>
> Could be counterfeit.

Point taken. I did notice that even the likes of Axminster Tools were only selling them at ~£150 (per Google Shopper) so £169 isn't too bad a price.

Yes, it's complete, yes it works, yes it's the "genuine article" (at least as far as I can tell!).

> I have on order a set of Rayban sunglasses, as
> hard a I try, I am quite sure they are counterfeit, if they arrive at
> all. The Seattle address is for the main Seattle newspaper, and they
> have concurred that they don't have an address there. :(

LOL! So the scammers used the address of a major newspaper in Seattle?
IME, they usually use addresses which just plain don't exist...

> Check out these Rotozip
> http://www.rotozip.com/en-us/Pages/CategoryDetail.aspx?pid=9_8#

I don't think I've ever seen a Rotozip tool in any of the local shops... they seem a bit thin on the ground outside of the USA...

> If you have a router, that should work if you make a jig to hold the
> work and guide the router.

I don't have a router -- what I have are a couple of 2mm tungsten-carbide PCB router bits which just happen to fit the Dremel.

> Sometimes I have spent much more time
> building a jig/guide that actual cutting, but end up with a neat hole.
> Just last night was watching a woodworking show on the TV, the whole
> show was on router jigs. :)

I wish we had shows like that on TV... closest we get to that is "Changing Rooms" or "Grand Designs". Neither of which is even remotely interesting...

And then there's X Factor and American Idol... I wish ITV would just give up on those shows, they really are atrocious. Lowest-common-denominator tripe at its very worst.

(though as long as Auntie Beeb retain some semblance of integrity, the TV license will continue to be paid... ITV could disappear entirely, and I'm not entirely sure I'd be able to give half a tweet, much less an entire hoot!)

-- Phil.
EraseMEpiclistspamEraseMEphilpem.me.uk
http://www.philpem.me.uk/

2011\02\11@122229 by Walter Banks

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Use a forstner bit. $10-$15 use water or alcohol as a coolant. This will
make very clean holes. I have used them on PVC caps for telescope
parts.


Regards,


w..
--
Walter Banks
Byte Craft Limited
http://www.bytecraft.com



2011\02\11@124107 by Carl Denk

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> The drill bit tended to slip in the chuck (it's covered in silver marks where the chuck jaws have spun around the bit).
> Hopefully it didn't damage the chuck...
>    Not likely to damage the chuck, just tears up the drill shank. Clean it up with a fine file.
>    
>
> It's pretty rare to see drill bits with a flattened shank around here.
> The vast majority are round -- even the PCB drills.
>    These are good quality industrial production machinery quality, but not that much more money.
>    
>> I always buy name brand that there are local repair stations for parts.
>> Long term well worth it. A lot better than at most inopportune time,
>> having to go chase tools.
>>      
>
> I don't think I've ever seen a Rotozip tool in any of the local shops...
> they seem a bit thin on the ground outside of the USA...
>    And on Walter's suggestion of Forstener bits, will have to try that, wouldn't have expected that to work. :)

What I saw those Dremel bits were very similar to the wood/plastic bits.
>    
>
> I wish we had shows like that on TV... closest we get to that is
> "Changing Rooms" or "Grand Designs". Neither of which is even remotely
> interesting...
>    We have Directv satelite, and there is a large variety available including a wide variety of Do it programs. :)
> And then there's X Factor and American Idol... I wish ITV would just
> give up on those shows, they really are atrocious.
> Lowest-common-denominator tripe at its very worst.
>    The local Fox TV channel news always is promoting "Idol", when I  hear that word, it's to a different channel

2011\02\11@124243 by Gary Crowell

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Just a comment, and I don't mean to sound pretentious or arrogant, or
anything; and I know it's not possible for everyone.  But, I think about the
hundreds of hours I've spent over the past 40 years flailing away at bits of
metal and plastic with files, hacksaws and various implements of
destruction...  and I can't believe I didn't buy a mill and lathe sooner.

Gary
----------------------------------------------
Gary A. Crowell Sr., P.E., CID+
Linkedin <http://www.linkedin.com/in/garyacrowellsr>
Elance<www.linkedin.com/redirect?url=http%3A%2F%2Fgaryacrowellsr%2Eelance%2Ecom&urlhash=kJm9>
 KE7FIZ <http://www.arrl.org

2011\02\11@133849 by Walter Banks

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Carl Denk wrote:

> And on Walter's suggestion of Forstener bits, will have to try that,
> wouldn't have expected that to work. :)
>
>

The trick with any cutting of plastic is to keep the bit cool. There have been
suggestions to pre freeze. I have done that works but a better way is to use
coolant to keep the plastic below its melting point as it being cut. Plastic is
an insulator and doesn't conduct heat very well so the bit needs to be cooled.
Alcohol is a good coolant because of its low boiling point. Water will work
quite well but needs more care. It the plastic starts to stick to the bit it isn't
cool enough.

For plastic caps that I have drilled I have usually used a mill or drill press
at relatively low speed.

w..

2011\02\11@144649 by William \Chops\ Westfield

face picon face

On Feb 11, 2011, at 10:38 AM, Walter Banks wrote:

> Alcohol is a good coolant because of its low boiling point.

Alcohol would make me very nervous, given the sparks I see the average  drill motor make.

BillW

2011\02\11@163322 by PICdude

flavicon
face
WD-40 and automatic transmission fluid make pretty decent coolants.


Quoting "William \"Chops\" Westfield" <@spam@westfw@spam@spamspam_OUTmac.com>:

>
> On Feb 11, 2011, at 10:38 AM, Walter Banks wrote:
>
>> Alcohol is a good coolant because of its low boiling point.
>
> Alcohol would make me very nervous, given the sparks I see the average
> drill motor make.
>
> BillW
>
>

2011\02\11@170354 by Walter Banks

picon face


PICdude wrote:

{Quote hidden}

It is always alcohol and water. I have never had a coolant
ignite. WD-40 will work well

w..

2011\02\14@093748 by Michael Rigby-Jones

flavicon
face


> -----Original Message-----
> From: .....piclist-bouncesspam_OUTspammit.edu [TakeThisOuTpiclist-bounces.....spamTakeThisOuTmit.edu] On
Behalf
{Quote hidden}

have
> been
> suggestions to pre freeze. I have done that works but a better way is
to
> use
> coolant to keep the plastic below its melting point as it being cut.
> Plastic is
> an insulator and doesn't conduct heat very well so the bit needs to be
> cooled.
> Alcohol is a good coolant because of its low boiling point. Water will
> work
> quite well but needs more care. It the plastic starts to stick to the
bit
> it isn't
> cool enough.
>
> For plastic caps that I have drilled I have usually used a mill or
drill
> press
> at relatively low speed.

I've even managed to use the "spade" bits designed for boring holes into
wood with great success on soft plastics like PVC.

Mike

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