How do I make thin circumerential grooves?

[Lee in Texas]

Like an o-ring groove, but really thin. I'm talking .010"-.030"and relatively deep (relative to an o-ring groove). Do I need to fabricate a way to hold a motor tool to my lathe cross slide? Is there a parting tool this thin?

It's for making models of thing like beehive oil filters and air-cooled engine cylinders (non-functional)

[Evan]

Not a good plan to link directly to a file like that, especially when it is 1800 pixels wide.

[edit] That's better.

Just regrind a cutoff blade.

[TGTool]

Lee,

There was an article in HSM or Machinist Workshop, within the last year or so, on using a slitting saw to make very thin grooves like that. It can be mounted on a small spindle and motorized to spread the cutting action over all the available teeth. That would give you considerable depth of cut, but if you need grooves on a long part you might need to make a special arbor, supported on both ends to get clearance.

[Swarf&Sparks]

"thin" and "deep" require quantifying, but here goes.....
I've used (broken or worn) donkey saw blades as parting tools.
Also used ordinary hacksaw blades on smaller jobs such as you describe.
The vacu-video method (AKA, suck it and see)

[Rif]

I have a couple of 1/4" HSS lathe tool bits that I have ground down to make narrow slits. Last week I used one, in my mini-mill, to make a slit for the valve in a carburetor shaft. Evan's suggestion of re-grinding a cutoff blade would work the same, as well and would be much faster to grind. I only used 1/4" HSS because I only have 1 cutoff blade; but, I have plenty of HSS tool bits.

Brian

[Rusty Marlin]

Funny you should ask this today.

Just yesterday I was grousing to the machinist here at work about hand grinding .025" grooving tools and how I'm having trouble keeping the sides parrel; without any hesitation he said, "Why don't you use an old hacksaw blade?" with that fatherly look on his face that adds "KIDS!" to the end of the question.
I hope he isn't planning on retiring anytime soon, he's full of great tips.

[ahidley]

Get a $3 carbide tipped circular saw blade and cut it up into approx 8 parting tools about 1"high x 4"long x the thickness. grind the carbide down to the desired width. If your cleaver you'll be able to mount it in your parting tool holder.

[speedsport]

do you mean like "Beaver Cleaver"?

[Scishopguy]

This brings up a question someone asked a while back, "What would I use a surface grinder for?" Over the years that I worked in Oceanography shop at FSU, I had to make tools to turn various O ring grooves in pressure case end bells and a variety of bulkhead penetrations. I found that I could grind a parting tool with the proper relief on the end of a high speed tool bit of any size. Some of the larger ones took a couple of hours to grind but, concidering the use I have gotten from them over the 26 years in that position it is not a lot of time wasted. The same tools came in handy over and over. The handiest ones I found to be .o62" and ,030" thick. The smallest one I made was .015" and was only used occasionally. The most rugged one was ground onto a 5/8" cobalt bit and was .100" thick. I used it to bore 8" diameter rounds out of a bunch of 1/2" thick stainless plates that became instrument hangers. Couldn't have done it without the good old surface grinder. Grooving tools and cutoff tools are some of the handiest tools in your collection of bits. Tool making and design is one of the most enjoyable parts of the machinist trade. Go out there and keep doing what you do, solve those tooling problems.

[GKman]

circumerential?

Aren't you supposed to get a Rabbi to do it?