Models for grinding HSS Lathe Tools

[WobblyHand]

My first thought for odd tool shapes is a die grinder/dremmel. I think I'd try to get the bulk of the material off with the belt grinder, then switch to the smaller tool. Probably hold on to the tool in a vise and cool with a squeeze bottle of water. I'm not sure what to suggest for grinding media though.

One alternative I have seen done on a Joe Pie video, cut in the mill with carbide tooling. It's probably tough on tooling, but it did work.

I'm interested in seeing what others suggest. I haven't made too many specialized tools.

Thanks for that. Guess I need to figure out how to make a clamp for the die grinder/dremel. I need to hold one item, not two... I find that holding the grinder is awkward and I'm always worried about wheel breakage and getting smacked in the face. I wear safety glasses, but, still when stuff breaks, stuff goes flying in an unpredictable fashion.

In the past I used a dremel and diamond files. The experience was slow, slow, slow and tedious. It was awkward using the dremel and the removal rate wasn't that quick. In the end, it did work, but took days of effort to finish the tool bit. Consequently, I have avoided doing it much.

Revisiting this, to find a way that is faster and hopefully a bit easier.

Trying to make something like this:

 

[ttabbal]

That is a tricky part. What does your tool look like?

For grinding, I like a full face shield. When something goes wrong, bits and grinding dust go everywhere. Less convenient for sure, but inexpensive and keeps junk out of the eyes, mouth, nose, etc..

 

[WobblyHand]

That is a tricky part. What does your tool look like?

For grinding, I like a full face shield. When something goes wrong, bits and grinding dust go everywhere. Less convenient for sure, but inexpensive and keeps junk out of the eyes, mouth, nose, etc..

Haven't designed the tool yet, might need two of them. Which is why I was asking the question about more efficient tool grinding.

I suppose the correct answer is some sort of real tool grinder, but unless one falls out of the sky, or I win the lottery, a nice tool grinder purchase isn't likely.

 

[rronald]

Greetings. I'm new here (just got a lathe) and I had some failing cuts that were at least partially due to a dull tool (made it dull it trying to cut rust). I was able to touch it on the grinder and get it working.....but I decided that I needed to learn how to grind tools. That brought me to this thread.

Doing some searches I dropped into page 11 of the thread where Mikey told how to grind keyway stock for the blanks. Yesterday, I made a version of his square tool from the instructions there. But I'm wondering if there's a specific guide that I should use versus reading thru all 186 pages of the thread?

I also have a few questions.

I have a terrible 5" grinder. I was looking at getting a better one....and then I stumbled on threads claiming a 2" belt sander is better. But, when I was doing the angles on my first attempt at a HSS lathe tool, I did the two side cuts using a 12" disk sander. It worked great! The disc sander has a good table and I can use the swivel for the table and a mitre gauge to precisely control angles. Removed metal quickly w/o a lot of heat and hardly even left a burr. The top relief can't be done on a disc, I used the terrible 5" bench grinder free hand. The grinder would probably be better with a new wheel. So, my equipment question (mostly for any cuts that can't be done on a flat surface) is....what's the most cost effective approach to be able to grind better? New wheel (5" seems to have limited options)? New grinder? Belt sander?

Since I'm here, I'll also ask if I'm in the ballpark on this tool:

 

[Aukai]

Pocket diamond lapping plates/cards will polish up the faces also, it makes for sharper edges.

diamond lapping cards - Google Search

 

[Aaron_W]

Greetings. I'm new here (just got a lathe) and I had some failing cuts that were at least partially due to a dull tool (made it dull it trying to cut rust). I was able to touch it on the grinder and get it working.....but I decided that I needed to learn how to grind tools. That brought me to this thread.

Doing some searches I dropped into page 11 of the thread where Mikey told how to grind keyway stock for the blanks. Yesterday, I made a version of his square tool from the instructions there. But I'm wondering if there's a specific guide that I should use versus reading thru all 186 pages of the thread?

I also have a few questions.

I have a terrible 5" grinder. I was looking at getting a better one....and then I stumbled on threads claiming a 2" belt sander is better. But, when I was doing the angles on my first attempt at a HSS lathe tool, I did the two side cuts using a 12" disk sander. It worked great! The disc sander has a good table and I can use the swivel for the table and a mitre gauge to precisely control angles. Removed metal quickly w/o a lot of heat and hardly even left a burr. The top relief can't be done on a disc, I used the terrible 5" bench grinder free hand. The grinder would probably be better with a new wheel. So, my equipment question (mostly for any cuts that can't be done on a flat surface) is....what's the most cost effective approach to be able to grind better? New wheel (5" seems to have limited options)? New grinder? Belt sander?

Since I'm here, I'll also ask if I'm in the ballpark on this tool:View attachment 462806

It requires searching through this thread but there are a couple of posts interspersed throughout that summarize the various tools discussed to that point.


Making a 2" belt sander is on my to do list, but while it is not perfect, my 8" bench grinder has not left me feeling inadequate. Seems to me a lot of the guys who own a nice belt sander still resort to a bench grinder for certain aspects of tool grinding. I've been quite happy with my Rikon 1hp low speed 8" grinder. When I finally wear out the white stones I'm thinking I will replace them with CBN wheels. It seems like this grinder will always continue to find a use as a dedicated tool grinder even after I finally get my belt sander built. I also do some woodworking so it does double duty sharpening some of those tools as well.

 

[mikey]

Your tool looks pretty good but I can't see the rake angles. A shot from the front of the tool will help. Also, you need to put a small nose rdius on your tool and hone all three faces. Otherwise, you did a fine job. For more detail on how to grind this tool, search for "How to grind a HSS lathe tool".

I've had extensive experience grinding tools with both a bench grinder and a belt sander and in my opinion you cannot beat a good belt sander for grinding lathe tools (and many other tasks). Ideally, you want a 2" wide belt and the sander must allow access to the right side of the platen. Search for "belt sanders tool grinding" and read up.

I don't expect anyone to read this whole thread. It is a monster at this point. However, if you wish to really understand how lathe tools work and how they are used then you might consider taking a deeper dive. I've read comments that the various tool angles on a turning tool are not important. I have ground more than 300 experimental tools and I KNOW that a tool ground with a specific tool geometry/angles can double or even triple the performance of a tool ground with stock or haphazard angles. I have a little Sherline lathe that will take a 0.060" deep cut in mild steel (0.120" off the diameter), then turn around and cut off 0.0001". Try that on any other lathe with only 0.08HP and you'll understand why I think tool geometry matters.

 

[ttabbal]

https://www.hobby-machinist.com/attachments/making-hss-tooling-for-the-lathe-pdf.245202/

Hope that works, it should link to a file with the most important posts distilled into one place. I call it the "Book of Mikey". It's in post number 312. Note that the numbers at the top and bottom are page numbers, the post number is in the top right of the post.

@rronald Your tool grind looks pretty good. Sharpening with diamond cards is quick and gives a cleaner cut, and lower cutting forces. The best, while still being reasonably priced grinder is to build a 2x72. Even DIY, they aren't "cheap", but they are really nice to use. You can modify wood sanders, but they don't work as well in most cases.

Wheel grinders do work, but tend to make concave faces that will be harder to hone. If you go that way, do some research into quality wheels. The wheels they come with are junk. I think you can use the side of the wheel as well, which would help with the shape of the grind. Your disc sander did a good job, so it might be worth while to get a nice disc for it. Try a ceramic 36 grit. If your speed is high enough, you can remove material super fast from HSS with one.

I use these diamond cards and like them... https://www.amazon.com/dp/B00006IIO...oding=UTF8&psc=1&ref=ppx_pop_mob_b_asin_title

 

[rronald]

Your tool looks pretty good but I can't see the rake angles. A shot from the front of the tool will help. Also, you need to put a small nose rdius on your tool and hone all three faces. Otherwise, you did a fine job. For more detail on how to grind this tool, search for "How to grind a HSS lathe tool".

I've had extensive experience grinding tools with both a bench grinder and a belt sander and in my opinion you cannot beat a good belt sander for grinding lathe tools (and many other tasks). Ideally, you want a 2" wide belt and the sander must allow access to the right side of the platen. Search for "belt sanders tool grinding" and read up.

I don't expect anyone to read this whole thread. It is a monster at this point. However, if you wish to really understand how lathe tools work and how they are used then you might consider taking a deeper dive. I've read comments that the various tool angles on a turning tool are not important. I have ground more than 300 experimental tools and I KNOW that a tool ground with a specific tool geometry/angles can double or even triple the performance of a tool ground with stock or haphazard angles. I have a little Sherline lathe that will take a 0.060" deep cut in mild steel (0.120" off the diameter), then turn around and cut off 0.0001". Try that on any other lathe with only 0.08HP and you'll understand why I think tool geometry matters.

Thanks for your comments.

Here's a pic looking at the front of the tool.

I did try honing a radius with a stone, but it's woefully small. I suspect that a hone is not sufficient and the radius needs grinding (the section of the thread that I used didn't have any radius instructions). I did find a .stl for a tool in the thread and printed one. I think I can duplicate that radius on the HSS cutter with my sanding disk.

 

[Aaron_W]

Wheel grinders do work, but tend to make concave faces that will be harder to hone. If you go that way, do some research into quality wheels. The wheels they come with are junk. I think you can use the side of the wheel as well, which would help with the shape of the grind. Your disc sander did a good job, so it might be worth while to get a nice disc for it. Try a ceramic 36 grit. If your speed is high enough, you can remove material super fast from HSS with one.

This is not always the case, more of the situation with cheaper "box store" grinders. My 8" Rikon came with good quality Norton white stones as it is marketed towards tool sharpening. The higher end Jet bench grinders also tend to come with white stones. The otherwise decent Dewalt grinder you get at Home Depot or Lowes for around $150 will probably come with cheaper grey stones since they are being sold as generic bench grinders and those stones work fine for somebody sharpening lawnmower blades, shaping steel parts and such.

As to the concave, bigger wheels and / or smaller cutting bits reduces the hollow ground factor. In my case running mostly 1/4" and 3/8" bits on an 8" wheel, I'd be surprised if there is any noticeable difference in the final grind vs a belt sander. 3/4" or 1" bits on a 6" wheel, then I could see that it might actually make a difference.

For me my desire for a belt sander is less about the quality of the tools cut with a bench grinder, as it is the work to do it. Stones are messy and the potential for a stone failing is never a pleasant thought.

It seems that a belt sander gives up nothing to a bench grinder, but there are very few quality belt sanders available at anything close to the price of a good quality bench grinder that doesn't require modification. Jet makes a nice 2x48" combo belt grinder / 6" disk or 8" bench grinder that some here have bought, but at $650 it is more than twice the price of a high quality 8" bench grinder, and still needs some work to make it suitable for grinding lathe tools. A DIY 2x72" or 2x48" will cost at least that much in materials even using scrap parts where possible to save money. I've been visiting my local metal supply with my parts list in hand to peruse their rack of cut offs, and I'm probably into it for $150-200 and only 3/4 the way there and that does not include coming up with a motor and the more specialized bits like the wheels.

I wish Mikey's Craftsman belt grinder was still available, but for whatever reason quality 2" belt grinders are not nearly as common (or as reasonably priced) as the 1" and 4" woodworking belt sanders.