Help With ID and Placement of HSS Turning/Side Tool On Sherline Tool Post

[Rob M]

Ok, once again showing my ignorance here but the more I look in the Sherline manual the more confused I get. In the attached JPGs is this High Speed Steel tool mounted correctly? Is it mounted upside down? Is it a left handed turning tool (moved from my left to right when facing or turning correct?) or a right handed tool (moved from my right to left when turning correct?). Either way I have been using it incorrectly some of the time since I used it to 'face' (feed left to right) and to 'turn' a piece of stock (feeding right to left). Have I already made it need to be resharpened? I can upload better/more JPGs if needed.

 

[Jerry Kieffer]

Rob
From what I can see, your HSS lathe tool is correctly mounted in the tool post.

In machinist terminology, your tool is a right hand lathe tool.

However, unless the tool cutting tip is not centered on spindle rotation, not much good will happen.
This can be done by filing a sharp tip on a work piece in the lathe spindle and adjusting the tip under optics per first attached photo.

It is my personal belief, that HSS lathe tools have a way of prolonging skill development for beginners.
All lathe tools have specific cutting characteristics when first used. If they are hand ground when required, then those specific characteristics change and skills must be in part remastered. The only way to prevent this would be to have expensive grinding equipment plus skills to operate it to exactly duplicate original profiles. In this case, skill development would continue to increase with each grinding.

Again personally, I use brazed carbide Lathe tools mounted and setup in additional double sides standard tool posts where the tool remains after setup, until replaced with a new tool of the same manufacture. In this case all tools have the same profiles and cutting characteristics. Almost all lathe tool work for is done with a AR-4 and E-4 or D-4 brazed carbide tooling. Discarded tools are saved and hand ground for non critical rough work. I generally grind HSS lathe tools for form tooling.

Brazed carbide lathe tools can be used for everything from rubber to the hardest steel that can be machined.

The second attached photo shows a pivot machined to .005". With proper tool setup, this can be easily done by a beginner on their first attempt.

Jerry Kieffer

 

[L. Vanice]

Grinding lathe tool bits is the first skill you need to use a lathe. The bit in the pictures has no side relief, so it is incorrectly ground for any metal. It has side rake, which makes it suited to turn steel. It looks like it has no end relief at the cutting edge and it looks dull at the point. In any case, the "point" should have a radius of some size in order to get a more or less smooth finish.

I have never seen a Sherline manual, so I do not know if it has useful tool grinding info. I can say that the South Bend How to Run a Lathe book has useful info on tool grinding, as do some other basic lathe books. South Bend revised their book many times, so there are many editions. Here is a free link to the 1958 edition. You can buy various print versions online.

South Bend Lathe Works - Publication Reprints - How To Run A Lathe 55th Edition | VintageMachinery.org

Brazed carbide RH and LH tool bits come ready ground with geometry suited for turning steel. The catch is that they need a diamond wheel to regrind them when the edge chips, so you still need grinding skill and equipment. Tools to turn brass should have no side or back rake, which makes them a little simpler to grind from a HS blank. Some brazed carbide bits are not suitable for brass, but will still cut.

I do not like rocker tool posts like the one in the pictures if you only have one of them. They can be set to the proper center height, but changing to a different bit will make you set it to center again. You can buy extra tool posts and leave each post set up with its own bit. Or you can use quick change tool post sets with extra holders, which work the same way. And QC holders have a screw height adjustment which is much better than a rocker.

A simple way to check height adjustment is to take a shallow facing cut on the end of a bar. Start a little low and leave a pip on the end of the work. Then gradually raise the bit and take another cut until there is no pip left.

Larry

 

[etmb61]

Best tool posts for Sherline.


They're as easy to use as a quick change and cost much less.

Eric

 

[the 3rd dwarve]

Rob,

I have to agree with Larry. You need to learn to sharpen your tools. If you are going to be turning a lot get a grinder and put a 60 or 80 grit wheel on one side and 100 grit blue Norton wheel on the other side. They are the best for HSS. If you use carbide tools you will need a green silicon-carbide wheel.

Make yourself a tool height gauge. I'll attach a picture of mine. All you need is a piece of round stock the same height as the distance from your cross slide to the lathe center line. Fasten a flat plate on top that the tooling can stop against.

If you don't have a copy of the Machinery's Handbook you should get one. You don't need the latest edition, get a used one off the big online auction site. They contain a wealth of information including a section on grinding HSS and carbide tools. I think the section on threads is worth the price of the book.

For most of the turning I do I use insert tooling. You can get high quality, USA made insert tooling in any shape, formulated for any material, for use on any job including heavy interrupted cuts.

Turning is the most fun you can have in the shop so be safe and have some fun.

D`

 

[Rob M]

Best tool posts for Sherline.
View attachment 765931

They're as easy to use as a quick change and cost much less.

Eric

Eric, Thanks for the info - I just got the 1/4 by 1/4 two sided post. I currently do not see myself using the larger sized tools but if I do I sure see the advantage of a two sided post. Thanks again.

 

[Rob M]

Jerry, Mr. Vanice and T (D') - Thank you for the good info. Getting a grinder is now on my 'need to get' list. However, I dont know what a tool in need of sharpening looks like. I still have 3 unused HSS tools from Sherline so I can use them as a sample of what a good one looks like.

Can you show me a JPG of one that needs sharpening? Is the Right Hand HSS tool I have in the JPGs a good example of a tool that is over-used and needs sharpening? I did use it to face a couple of small parts (less than 8) cutting left to right so I likely did some damage that a sharpening may fix. Does this damaged one look the same as one that is dull from use?

 

[bartmes]

Jerry:
I know from past posts you have an Accufinish machine. Do you use it to dress or sharpen brazed carbide tip tools? If so could you show what you do. In advance, thanks.

 

[Jerry Kieffer]

Jerry:
I know from past posts you have an Accufinish machine. Do you use it to dress or sharpen brazed carbide tip tools? If so could you show what you do. In advance, thanks.

Bartmes
First, I should mention that I only use brazed carbide tools made in the USA and Europe of high quality. The inexpensive Imports from China and India have been of little value.

In addition, these tools when used in Sherline size and type of lathe with metals designed to be machined, can of course chip but it has been no issue. Manufacturers do a lot of research and testing on tool performance in order to stay competitive with competition. Thus I am able to duplicate micro parts such as watch parts not only to exact dimension, but also surface finishes unlike hand ground HSS. Once properly setup in a tool post, I normally get anywhere from about 50 hours to 100 hours use before replacement. It has also been my experience for whatever reason, that these tools resharpened rarely achieve the same level of performance as a new tool. Because of the low cost, I replace the tool with a new tool rather than resharpen them where quality work is required. As mentioned, they are then saved and hand ground on a bench grinder for rough work where chipping can be more common.

To answer your question, I use the series 1 Accu-Finish grinder.
Per the first attached Photo, the standard table is fully adjustable to all angles and relief grinding angles. Just follow Instructions for use.

The second attached photo shows grinding the same tool with the assistance of two parallels. If this were something I did on a daily basis, there are factory fixtures or they could be easily machined for holding any tool. In this case since I only seldom grind brazed carbide in this machine, The quick parallel setup has worked without issue.

Jerry Kieffer

 

[bartmes]

Jerry: Thanks for the information.

 

[Rob M]

Make yourself a tool height gauge. I'll attach a picture of mine. All you need is a piece of round stock the same height as the distance from your cross slide to the lathe center line. Fasten a flat plate on top that the tooling can stop against.

D`

View attachment 765958

Your Tool Height Gauge looks like an edge finder. Could I get a cheap edge finder and cut it off to the correct height?

 

[Vernon]

Rob, Sherline makes one. I'm in need of one myself. Lathe Tool Height Gauge – Sherline Products

Vernon

 

[Rob M]

Grinding lathe tool bits is the first skill you need to use a lathe. The bit in the pictures has no side relief, so it is incorrectly ground for any metal. It has side rake, which makes it suited to turn steel. It looks like it has no end relief at the cutting edge and it looks dull at the point. In any case, the "point" should have a radius of some size in order to get a more or less smooth finish.

I am looking at a Delta 6" or 8" bench grinder to sharpen my HSS tools. Can you tell me which type of grinding wheels I should be using to do this? I am more inclined to buy the 8" - I assume it will give me more options but I also assume the wheels will cost more. Any opinion on 6" or 8" inch bench grinders?

 

[the 3rd dwarve]

Rob,

I would recommend a six inch wheel grinder unless you get a 1750 RPM grinder.

At 3450 RPM six inch wheel will have a rim speed of 18876 inches per minute while an eight inch wheel will have a rim speed of 25162 inches a minute. At the higher rim speed it will be easier to burn the HSS.

For HSS I prefer Norton premium blue ceramic alumina wheels.

PROs: They cut fast, don't burn, and last a long time.

CONs: They are expensive.

Keep your eyes open for a good quality 1750 RPM grinder or a good quality three phase 3450 RPM grinder and use a VFC to adjust the speed.

You could probably make a height gauge from a center finder but I would like something larger in diameter.

D`

 

[Rob M]

Rob,

I would recommend a six inch wheel grinder unless you get a 1750 RPM grinder.

At 3450 RPM six inch wheel will have a rim speed of 18876 inches per minute while an eight inch wheel will have a rim speed of 25162 inches a minute. At the higher rim speed it will be easier to burn the HSS. ................................ Keep your eyes open for a good quality 1750 RPM grinder or a good quality three phase 3450 RPM grinder and use a VFC to adjust the speed.

3rd/D,
Thanks. All good info on wheels and guage. I was a bit confused on the RPM speed. I thought when you said, "Burn" you meant grind. It sounds like the slower RPM the better. I will look for that 1,750 or 3,450 you mentioned. Oh, and is VFC, variable speed control?

 

[the 3rd dwarve]

Rob,

Rob,

When grinding HSS you can exceed the quenching temperature of the steel and the result of that is a severe decrease in the hardness of the steel rendering it useless as a cutting tool. The slower speed of the wheel decreases the chance of burning the steel. Keep a water bath at the grinder and keep the tool cool.

VFCs are more than speed control. They convert single phase, 220V house power into 220V three phase power. In addition they can ramp up start power and provide braking.

D`