I have a recurring need to reach inside a closed space and grind a weld.
Sometimes I have enough room to get a right angle die grinder in
there, if I distort the shape, but then I have to distort the shape
back, which is kind of a pain. Sometimes there is not enough space to
do that, depending on the size. I use a 2 inch Roloc disk on the die
grinder as a kind of miniature right angle grinder. The headroom
requirement for that setup is 4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld. The Roloc disk
mounts on a 1/4 inch shaft, so perhaps I could put two bearings and a
pulley on that 1/4 inch shaft, and then run a drive belt to the die
grinder, which would have another pulley on it, using a 1/4 inch shaft
mounted in the die grinder. The sketch at the link below should help, I
always have trouble visualizing what people describe in words, a picture
is worth a thousand words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would
survive that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard


--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

Richard:
Google Dynafile. I've also seen belt attachments for right angle 4.5"
grinders. Check with your abrasives dealer.
-Mike

I've used band grinders for close quarters, if there's room enough. HF
has a conversion kit for an angle grinder cheap, if you just want to
try the concept out. I've got my eye on one of the pneumatic dedicated
units, though. The HF unit works well for snagging castings and welds
in odd spots. Just not going to be that long-lived, it's cheaply
built.

Here's one type, there's other sizes:
http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

There's also a pneumatic right-angle micro die grinder:
http://www.use-enco.com/CGI/INSRIT?P...PMAKA=801-1685

Both on sale, how's that for timing?

Hope this gives you some ideas

Stan

At 20,000 RPM, I'd say BELT.
Less stored energy when the chain breaks.

For this you want the smallest pulleys possible to keep the linear
speed down- less stored energy.

20Krpm, 1 inch diameter pulley, the belt's moving at, lets see...

dist at edge = radius times theta, theta is 2pi, 2 x 0.5 xpi = pi
inches per rotation. 20,000 pi is 62831.
So 62.832e3 inches per minute, or 87.3 ft/s or just about 60 mph (which
is 88ft/s).

Not sure a belt will survive turning a tight radius at these speeds.

Maybe a housing with a shaft drive and bevel gears might be found?
You could come straight off the die grinder and just do 1 90-turn at
the head.

Dave

Richard Ferguson wrote:

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld.

Are you looking for something like this?
http://www.werkzeugfachmarkt.de/shop...shop/cl/detail
s/cnid/9b64417fdb436eb14.00669661/anid/3e54224fde069aed7.39029057/Winkel
schleifer-MSfv-649/

The picture at www.fein.com is broken, so you have to live with the
german text. For english description, see Fein's homepage and use this
article number: "MSfv 649"

We call that "long neck angle grinder".


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO // Eigenbau-Digitalanzeige
http://www.yadro.de

Richard Ferguson wrote:
I have a recurring need to reach inside a closed space and grind a
weld. Sometimes I have enough room to get a right angle die grinder
in there, if I distort the shape, but then I have to distort the shape
back, which is kind of a pain. Sometimes there is not enough space to
do that, depending on the size. I use a 2 inch Roloc disk on the die
grinder as a kind of miniature right angle grinder. The headroom
requirement for that setup is 4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically
offsetting the Roloc disk a few inches via a drive belt or chain, to
reduce the headroom required to get inside and grind the weld. The
Roloc disk mounts on a 1/4 inch shaft, so perhaps I could put two
bearings and a pulley on that 1/4 inch shaft, and then run a drive
belt to the die grinder, which would have another pulley on it, using
a 1/4 inch shaft mounted in the die grinder. The sketch at the link
below should help, I always have trouble visualizing what people
describe in words, a picture is worth a thousand words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would
survive that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard

Google Porter-Cable offset router base for ideas on how this can be done .
They use a belt to drive a cog pulley that's less than an inch in diameter .
Also has a collet for 1/4" tooling ...

--
Snag aka OSG #1
'76 FLH "Bag Lady"
BS132 SENS NEWT
"A hand shift is a manly shift ."
shamelessly stolen
none to one to reply

On Fri, 14 Apr 2006 16:18:10 GMT, Richard Ferguson
wrote:

I have a recurring need to reach inside a closed space and grind a weld.
Sometimes I have enough room to get a right angle die grinder in
there, if I distort the shape, but then I have to distort the shape
back, which is kind of a pain. Sometimes there is not enough space to
do that, depending on the size. I use a 2 inch Roloc disk on the die
grinder as a kind of miniature right angle grinder. The headroom
requirement for that setup is 4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld. The Roloc disk
mounts on a 1/4 inch shaft, so perhaps I could put two bearings and a
pulley on that 1/4 inch shaft, and then run a drive belt to the die
grinder, which would have another pulley on it, using a 1/4 inch shaft
mounted in the die grinder. The sketch at the link below should help, I
always have trouble visualizing what people describe in words, a picture
is worth a thousand words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would
survive that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard

I have one of these:

http://www.toolsforless.com/product/6355.html

The threaded part of the collet nose on mine looks like 5/8" - 24TPI,
YMMV. (Mine was bought 20 years ago) If you unscrewed the collet
ring, remove the collet and cut the collet housing off just at the end
of the threads (leaving the threads), the height would then be about
2.1". Perhaps you could then make an adaptor that screws on to that
and accepts your Roloc wheels.

You might have to tape the trigger down and use an external air valve,
as from a blowoff nozzle.

C.C. Specialty makes a heavy-duty 90-degree head for the Foredom style
flexible shaft porting tools that might work if you must have the tool
perpendicular to the weld: http://ccspecialtytool.com/pages/page03.html
I think I would try using an oval-shaped carbide burr on straight
handpiece first.
David


"Richard Ferguson" wrote in message
...
I have a recurring need to reach inside a closed space and grind a weld.
Sometimes I have enough room to get a right angle die grinder in there, if
I distort the shape, but then I have to distort the shape back, which is
kind of a pain. Sometimes there is not enough space to do that, depending
on the size. I use a 2 inch Roloc disk on the die grinder as a kind of
miniature right angle grinder. The headroom requirement for that setup is
4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld. The Roloc disk mounts
on a 1/4 inch shaft, so perhaps I could put two bearings and a pulley on
that 1/4 inch shaft, and then run a drive belt to the die grinder, which
would have another pulley on it, using a 1/4 inch shaft mounted in the die
grinder. The sketch at the link below should help, I always have trouble
visualizing what people describe in words, a picture is worth a thousand
words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would survive
that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard


--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

I am really impressed with all the ideas that people came up with. I
usually get good advice here, but these were really good, and everyone
had a different approach. I went ahead and ordered the angle die grinder
from Enco, 801-1685, even though the information about it was sketchy,
just a tiny photo. I hope that it has a pad to accept
pressure-sensitive sanding disks in some standard size. They said that
I could return it within 30 days if I don't use it. It looks a little
on the wimpy side, but with patience I think that it would work. It
looks like a very small tool with maybe 2 inches of headroom needed, but
I will get to see it next week.

After having my eyes opened, I found some alternative approaches that no
one has yet suggested.

1. Buy a right angle adapter for a Dremel, and mount a sanding disk on
it. Micromark has 1" dia pressure sensitive disk pads with 1/8 inch
shank. (One of the problems that I found was that almost all the
sanding disk pads had 1/4 inch shanks, so incompatible with Dremels,
Foredoms, etc.).

2. Micromark has a small right angle sander with a 2 3/8 inch diameter
sanding disk. It runs on 12 volts. I would also have to buy the disks
from them, as that is not a standard size of pressure sensitive sanding
disks, at least in the USA.

3. There are 2 inch dia. air powered disk sanders available for
$300-$500 US. The ones in the MSC catalog are made by Dotco and
Dynabrade. These look like right angle die grinders with a sanding disk
pad, but appear to require less headroom than a standard right angle die
grinder with a separate disk pad. This option is rather expensive, and
I am not sure how much headroom I would pick up, so this does not look
very attractive at this point. I found one catalog that indicated a
height of 3 3/4 inch, not much better than my current 4 inch height. But
I expect that these would be powerful industrial tools. I put a lot of
hours on my current right angle die grinder with sanding disks on it,
maybe it is worth it to upgrade.

From the catalogs, it is hard to determine the actual headroom that
each tool needs, that number does not seem to be listed, so you have to
guess based on the photo and whatever other dimensions are provided.

Thanks to everyone for their thoughts, and I will watch to see what else
people think of.

Richard



Richard Ferguson wrote:
I have a recurring need to reach inside a closed space and grind a weld.
Sometimes I have enough room to get a right angle die grinder in there,
if I distort the shape, but then I have to distort the shape back, which
is kind of a pain. Sometimes there is not enough space to do that,
depending on the size. I use a 2 inch Roloc disk on the die grinder as
a kind of miniature right angle grinder. The headroom requirement for
that setup is 4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld. The Roloc disk
mounts on a 1/4 inch shaft, so perhaps I could put two bearings and a
pulley on that 1/4 inch shaft, and then run a drive belt to the die
grinder, which would have another pulley on it, using a 1/4 inch shaft
mounted in the die grinder. The sketch at the link below should help, I
always have trouble visualizing what people describe in words, a picture
is worth a thousand words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would
survive that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard




--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

I like the style of that grinder, very low headroom, but it looks like
it is too big. I don't read German, what is the disk diameter? My
guess is that the disk diameter is 125mm, which would be 5 inches or so,
much too big for my application.

Richard



Nick Müller wrote:

Richard Ferguson wrote:


I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld.


Are you looking for something like this?
http://www.werkzeugfachmarkt.de/shop...shop/cl/detail
s/cnid/9b64417fdb436eb14.00669661/anid/3e54224fde069aed7.39029057/Winkel
schleifer-MSfv-649/

The picture at www.fein.com is broken, so you have to live with the
german text. For english description, see Fein's homepage and use this
article number: "MSfv 649"

We call that "long neck angle grinder".


Nick


--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

Richard Ferguson wrote:

I like the style of that grinder, very low headroom, but it looks like
it is too big. I don't read German, what is the disk diameter? My
guess is that the disk diameter is 125mm, which would be 5 inches or so,
much too big for my application.


The technical data can be found here, as I sayed: www.fein.com article
"MSfv 649"


If you want it smaller, then look a www.proxxon.com for a similar but
smaller product. But if the long-neck grinder is as bad as their
homepage is ....


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO // Eigenbau-Digitalanzeige
http://www.yadro.de

I like the Proxxon long neck grinder, it looks like the right tool to
meet my needs. It is available from a variety of sources in the USA,
mostly wood carving or model making suppliers. Of course I cannot tell
the quality from the web. The only downside is that the 2 inch disks are
kind of oddball, so you may have to buy the Proxxon disks. I may buy
one even if the little angle grinder from Enco works out, I have a
feeling that the Proxxon would be more powerful than a tiny angle die
grinder.

Richard



Nick Müller wrote:
Richard Ferguson wrote:


I like the style of that grinder, very low headroom, but it looks like
it is too big. I don't read German, what is the disk diameter? My
guess is that the disk diameter is 125mm, which would be 5 inches or so,
much too big for my application.



The technical data can be found here, as I sayed: www.fein.com article
"MSfv 649"


If you want it smaller, then look a www.proxxon.com for a similar but
smaller product. But if the long-neck grinder is as bad as their
homepage is ....


Nick


--
http://www.fergusonsculpture.com
Sculptures in copper and other metals

As I noted in an earlier post, I ordered the mini angle die grinder
from Enco, 801-1685. When I got it, I found that it used very strange
donut shaped pressure sensitive sanding disks, and I had no idea where
to get more. The package that I had appeared to have been opened. I
suspect that someone else had bought it, figured that he could not get
these abrasive disks, and returned it to Enco.

I liked the die grinder, so I started thinking about how I could
convert it to use standard abrasives. The backing pad screwed on using
a 7 mm by 0.75 pitch thread, kind of an odd thread. What I ended up doing
was buying a 1" Roloc backing pad and a tap for the 7 mm thread. I
drilled out the 1/4 inch threads in the Roloc backing pad, retapped it
to 7 mm, and that got me to where I could use standard Roloc abrasives.
The headroom required is 2.5 inches, a big improvement over 4 inches.

I have only used it to try it, but I think that it is going to help me
with my sanding problem.

I did like the small long neck angle grinder that someone suggested,
but it uses special abrasives, not available from the standard
industrial suppliers. I may yet end up buying one.

The rec.crafts.metalworking crew came up with solutions, again. Thanks
to all.

Richard




Richard Ferguson wrote:
I have a recurring need to reach inside a closed space and grind a weld.
Sometimes I have enough room to get a right angle die grinder in there,
if I distort the shape, but then I have to distort the shape back, which
is kind of a pain. Sometimes there is not enough space to do that,
depending on the size. I use a 2 inch Roloc disk on the die grinder as
a kind of miniature right angle grinder. The headroom requirement for
that setup is 4 inches, more than I would like.

I was thinking that I might make a stationary tool, basically offsetting
the Roloc disk a few inches via a drive belt or chain, to reduce the
headroom required to get inside and grind the weld. The Roloc disk
mounts on a 1/4 inch shaft, so perhaps I could put two bearings and a
pulley on that 1/4 inch shaft, and then run a drive belt to the die
grinder, which would have another pulley on it, using a 1/4 inch shaft
mounted in the die grinder. The sketch at the link below should help, I
always have trouble visualizing what people describe in words, a picture
is worth a thousand words, etc.

http://fergusonsculpture.home.att.net/offset_roloc.jpg

The problem with this concept is that die grinders typically turn at
20,000 RPM. Are there any small drive belts or chains that would
survive that kinds of speeds?

Maybe there is another solution that I have not considered.

Richard




--
http://www.fergusonsculpture.com
Sculptures in copper and other metals