Next time you want to fine tune a chip breaker, use a 1/4" shank mounted chain saw sharpening point. You get 3 or 5 in a blister pack. You get better finishes and the grinding striations align with the chip flow. And you can doctor up a dull tool up on the lathe.

W/S's tooling division, Manchester, makes a series of trepanning tooling that is very versatile. Trepanning tools may also be made from braised on carbide cut-off tools. Spelling courtesy Microsoft. However, brazing requires a rigid machine. If chatter is encountered, try removing the top-jaws, and running from the masters. The removal of 2-1/2" of overhang can make all the difference. I used to occasionally make beer fittings for the Olympia brewery, and trepanning face grooves in red brass, and SS, was commonplace. The finishes are easily food grade. Even on loose, old dogs. Mark

I remember spending way too much time on trepanning tools when I was training.We were taught to leave as much material as possible for the 'outer' curve then 'match it' to diameter required but include 7 deg clearance. Our tutor could be a right ass sometimes. Setting 0.010"~0.015" above centre gives some extra clearance and sometimes a better cut. Angle grinder would have been a great thing to have back then

Nicely done, I especially enjoyed the part where you got the chip breaker right and decided to quit before bozo showed up. I usually never quit until it is too late. lol

Great video Tom! I love using these types of tools.

Hi Tom New to your vids.i was directed to you by BlondieHacks.I have a part to make involving surface grooves and thought back to my days as a machine operator when I used trepanning a lot. But that was back in the 60,s(not 1860)and it was all set up for me as an operator by the setter.Your video brings it all back beautifully. Thanks a lot and keep em coming.

Very cool. I've watched a number of videos using one of these, but none that made one. Thank you. Now I need a cut off tool.

awesome man saved my day literally. don`t need the ring but have to make a lot of o ring grooves. 100% agree on developing the skill of grinding hss and knowing how to homebrew cutting fluids too. thanks tom. take care. pete

Nice demo, Tom. Very similar to how I do it, too. I use the same type of tool for a recurring job I do for a Coleman lantern parts business. If you look inside the fuel cap on an older (pre 1970) Coleman white gas lantern, you will see one of the types of parts I make for them. There is a brass insert inside the fuel cap, held in by a screw, and that brass insert has a groove for a rubber gasket. My tool grind to make that groove is so much like what you show here, but smaller, as needed. I just happen to have an order of 600 of those parts in the shop right now. Trepanning my can off. :) For some of the gents below who mentioned having a hard time cutting a chip breaker on the grinder, try holding your tool bit in a vise and use a Dremel tool with a thin grinder blade. It is a little easier to control, for me, anyway.

great video Tom. I like the idea of using the right angle grinder with a cut off wheel to save time !

I've actually been needing to grind one of these for o-ring grooves on a face, but haven't been brave enough yet. This guide is just what I needed!

Thanks Tom, another excellent and informative video. I actually liked the no guard grinder, simply because they get in the way, and really, you're supposed to be in control of the tool, not the other way around.

Great information and tutorial Tom. Enjoyed learning something new today. Thanks for sharing.

great example of practical machining using advanced tooling techniques and frugal methodology.

Very interesting for me: not only to make rings and save material, but also to make frontal grooving, that is what i have to do now! So super thanks from Italy !! Alberto

Very good video. I’m still at it after over 50 years. One thing I make my apprentices do is grind their own tools(sometimes). They seem to hate for doing so but they thank me later. It helps in learning visualization skills. Thanks.

SWEET IDEA. Thank you Tom, I definitely will put this too to use. Thank you for posting this as well as the hundreds of other videos that you have produced for us through the years. Your expert machinist skills coupled with thinking outside the box is a great boost to all who view your channel.

Thanks for this useful video. I’ve been pondering how to cut rings from 2 inch dia phosphor bronze for several days now. In general I hate the waste of time and material from boring large holes in anything, so I’ll be using this technique as often as I can.

Nice and handy. A definite advantage to a shop which knows how to make or select the best tool for the job.

Nicely ground toolbit. When i was an apprentice in RDN, I were only tought to grind toolbits. As you say, anything is possible, and even today, allmost 40 years on, I hardly ever uses an insert.

Thank you for the thorough explanation and example. My dad and I got talking about drills. I made a joke about the medical practice of trepanning and he said there was a similar workshop term using a lathe. Found your video and we both learned something today. This is really cool. Thanks.

That clears up a question I had for a long time. A friend gave me some HSS tools when I bought my first Myford and one was this tool, but he couldn't tell me what it was for. The only time I used it, it was as a parting off tool.

Hey Tom you your giving away all of my grinding stunts ether way that's an awesome lathe tool

Great video Tom! I use this technique making 4" dia. PET seals that are.08 cross section. I end up with a 3.62 dia, chunk of material left that other parts can be made from. ATB, Robin

I'm most familiar with deep hole trepanning after seeing a number of machines at an auction. One machine could drill an 18 inch hole 19 FEET deep, if I remember correctly. Apparently it is used in the oil/petrochemical industries to make extremely large pipe with very heavy walls.

Catching up on things I had missed. Very nice job explaining how and why you grind a high speed tool for a special job. Makes me want to go out to the shop and play with the lathe for a while. Take Care and Stay Safe. Bob

Tom You are one smart guy with exceptional bench skills.

Neat! It's always a pleasure to spend some time listening to a guy who really understands what he's doing. I hope someday to work in a place where there are people like Tom Lipton around.

needed to learn how to make that tool for future jobs. PS thanks for the couple of items I purchased from you at the Bar Z swapmeet. Used the mike a few times already. Still need to install the high pressure gage.

Wow: a new word, a new tool bit design and a new technique. Very good lesson.

Must of been reading my mind. Exactly what I need!!

Makes sense after seeing a pro do the magic. Lot of great information on tool geometry and what to look for. Thanks

Tom, EXCELLENT VIDEO! I've previously searched for a video on this tool (& came up empty), particularly for a quicker way to cut a round out of square plate stock, without having to spend soooo much time cutting the square corners off a chip at a time (think pulleys). Pay no attention to all of the safety complainers, or the confused comments about terminology or grinding/red hardness... Definitely the best trepanning bit video on the Tube! Thanks for taking us along.

Nice tool grinding, Just in time for me I'm making some bearing race compressors out of 0-1 tool steel and wanted to save the center of the stock for another project, this will be perfect. Thanks for the detail, Eric

Very informative video Tom; great as always. Just seeing that in action was giving me some ideas about possible applications. Thanks!

Great video. I can see this being useful. I am not sure why I have never considered using a but off wheel on tool bits before. It certainly is a lot faster than grinding to get the rough scape.

Making these tools for trepanning to make a .040 groove .150 deep with an ID of .250 and outer groove OD of .330 will teach you all about the clearances needed. I make these type of tools often in my work.

detailed and precise explanation....I should sketch the blank cobalt as you do to make the grinding easier....

You certainly made it look easy. Thanks for the video.

Thanks for sharing your knowledge

Very Nice, I like how you explained the need for clearing the outside surface of the of the tool. it is a real neat solution. Not to change the subject, but changing the subject. I want to tell you that I really enjoyed the video on the differential screw. I hope that you have more videos where you make tools that use that principle. I liked how the screw controls very fine movements over short distances. The only complaint I have about your videos is that there are not enough of them. Keep up the good work. P. S. I met you at the bash (6/24) and I hope to come and visit you at your shop some day. I'll definitely call first and make sure that you have some free time. I promise to not spend all day checking out the shop (:-).

Lol There you go . Not many machinists no how to build a cutter like this anymore . Great job . Old Tool Maker JT Hay Fort Worth Texas

Fantastic... I once did it using a hss power saw blade that was broken on some brass material for training of some trainees.. Glad to get some new idea from you. Thanks for sharing 🙏🏻

Thank you for covering this in great detail, I have had mixed success with trepanning but this demonstration gives me confidence.

Woodworkers use similar techniques to save material when turning bowls on the lathe. They can get two or three bowls out of the same block.

Extremely useful video, both for the trepanning and the hint on tool grinding. Thanks!

Thank you Tom. Elegant simplicity is always great

Excellent video! Thanks. I made similar tools for cutting large holes in the face of a half inch plate but after watching this video I suspect my next tool will function better.

Good video, learn something new with every video you put out. Thanks for sharing

I made a small groove bit for the seal on a air gun barrel talk about small and fragile LOL I enjoyed your video Thank you for taking the time I never thought about making a ring but now I know if I need one

Enjoyed that lesson. Thanks for sharing!

Nice job Tom. It was lovely to see the chip curling away so smoothly from a shop made tool. It reminded me of when I was making hand planes some years ago and the pleasure I got when the plane produced a long, thin, curling shavings. B

Nice job on the Trepanning tool, It is all new to me ,but i like it.

We once used a "face groove" carbide insert tool for a project at work. Basically the exact same thing you just made except I think the manufacturer was a little embarrassed of the depth capable. I think we needed 8 pieces and would use an insert and a half on one part, not particularly difficult material either. I think we ended up relocating the op on the next batch and milling the faces for the o-ring seats in one of our live tooling lathes. great video as always.

Being subscribed to Tom's channel is like having a pocket index. You may see him do something years ago and at the time think that's cool. Then when you need it you think how did Tom do that again, let's look it up.

Thanks Tom, I just did some trepanning today. I didn't grind the tool at an offset as you did but I can see the benefit to the offset.

Thanks Tom. Liked the video subject and also the video format. Cheers.

Simply AWESOME .. I don't have one Tom , Going to make one ASAP !! Thumbs up ..

Great tip Tom, many applications, O-ring grooves springs to mind, I've also used trepanning to cut large holes in 3mm plate clamped on a face plate in the lathe works like single point annular cutter. Regards Ralph

Tom, Excellent video! This lesson will really come in handy, well done my friend!

I was looking exactly the same tool.I remember David wilks trepanning tool

Hey, Tom, great video. I've done this in a mill but never thought of it as a way to economize on expensive round (or hex!) stock. Very practical. Thanks again.

Thanks Tom, heard about lathe trepanning a long time ago now I will have a clue when trying to make one , thanks for the cutting disk tip.

Little gem for the mental tool kit there Tom, cheers :)

Thanks Tom for showing this... got just the project needing me to grind one!

Thank you mr Lipton Ian South Africa

I enjoyed that Tom - good to see HSS being used - we home shop chaps seldom have the larger lathes capable of getting the best from insert tools. Tried trepanning on some aluminium round stock a while back - it got interesting when I got more than 0.500" deep ... sticky stuff and the fine honed edge still got gummed up - thankfully I didn't need too many rings.

Thanks for the demo Tom. I've heard of this method but never seen it in action. Cheers

Thank You Tom! I cannot express how much I learned from this video. Of course I'm just wanna-be home machinist. My next door neighbor is real machinist and gets tired of my constant requests for information. 73, Bob

That's a neat trick Tom! I'll have to lock that a way in the old noggin. I work with a guy that saves used carbide grooving inserts and regrinds them for special jobs. It's always cool to learn something new like that.

Great demonstration. I thought that I was the only one that used a cut-off tool to rough out a tool bit.

Great lesson!

When I think of trepanning, I think of putting holes in someone's skull, which usually uses some sort of annular cutter not unlike a hole saw. I suppose you could do the same thing on a lathe if you had an annular cutter of the right size mounted on the tailstock.

That's very useful. I think I have one of those tools but I didn't know what it was!

Thanks Tom. That'll come in handy.

Great video and very clearly explained and demonstrated. Thanks for posting this Tom!

Thanks, just the information I was looking for

Tom great demo and comentery Will

That was awesome! Thanks for showing us how it's done!

Very cool , I will be ordering some more HSS .

great that you posted this! I need to do something just like this and was puzzling over the tool geometry. TYSM! now I know what this is called haha. annular cutting, face grooving and trepanning

Great tip and demonstration! Thanks Tom!

Hi Tom . Thanks for your informative channel . I sometimes use a small ball shaped diamond burr , to make an indent , where you put your positive relief , at the front end of the tool . this causes the shavings to go concave and pull away from the job .

You can use those diamond coated discs used for cutting stone and ceramics to cut away the bulk of the HSS bit. It cuts HSS really fast and produces a lot less friction.

Great solution to that problem! Nicely done!

Super useful! Got me out of trouble for which very many thanks!

Another use for my angle grinder ! (roughing out tool bits)

Brilliant tutorial

I just had a job with a 2" deep face groove 3/8" wide. Tried it with high speed but gave up and bought a long series annular cutter and finished it with a small boring bar.

Amazing that there is so much to learn. This was informative and knowing that I can cut tool steel with an angle grinder is a big help. I love the Flexovit 0,8mm thick cutoff blades which makes cutting steel something like cutting butter compared to even a 1.0mm thick blade. Nice video for sure. Thanks for sharing!

Just learnt something new Tom thanks mate love all your videos.

awesome video Mr. Tom

Always an interesting time watching you Tom. enjoyed the tour of the high energy physics lab you did great to know our high tech is being serviced by American professional machinists

We call it a (tree-pan), trepan tool, the act of using it is called trepanning. Great video! Thank for sharing.

This Trepanning seems to be a bit of a trick. Nice work.

Thanks for the vid and the info. Wish I had thought of the cut off wheel or seen this video a couple of weeks ago, I ordered a piece of 16mm square Fagersta 10% Co and made a double ended chamfer tool and that stuff is HARD to grind away. Took me a long time to grind away the 45 degree bevels. I guess it was my own fault since I used a cutoff wheel in a dremel to cut it to length and never gave thought to cutting the bevels away.

Like the use of your cutoff grinder for this

Didn't know that's what it was called, but done it myself in the past worked very well, nice to see a true pro working with H S S. 👍

Blind monkeys can find nuts too Tom. Nice video, and you make a good point about knowing how to grind the tool you need when you need it. You can use a trepanning tool in combination with friction drive to make disks out of thin materials as well, very useful info. Thanks!

Thank you for an other informative Video. I am new at metal working and love these instructive videos.