Member postings for Eccentric Engineer

Hi John

I tried a number of different rake angles on various materials to see which cut better when I was designing the FoR holder.
The only difference I found in cutting ability was that a blade with zero rake angle required slightly more pressure to push than one with 5 or 7 degrees rake, there was no discernible difference in surface finish.
Having zero rake can be an advantage as it gives a bit of back pressure and there is less likelihood of the cutting edge hogging in to the work.

I think the advantages of being able to keep the blade on centre when moving it in or out, less chance of digging in, and the ability to part off a wide range of materials with the blade held horizontal outweigh the pros of having the blade held at an angle, namely that it is easier to push.
If you were using a wide blade on a big lathe it may be more important.

Cheers

Gary
(Eccentric Engineering)

Hi Eric

Yes you are correct about the outside edge having the best cutting properties, and that works well with tangential tool holders.
However, the cast alloy doesn't lose hardness as soon as you grind through the surface, although its cutting ability does lessen as you get closer to the centre of the tool bit. The stock has already been ground down to size from a casting at the manufacturers anyway.

For a normal knife tool it would be fine as you are not removing much material, but for say a thin grooving tool where you are grinding off a lot of the stock on either side it would be better to use HSS instead.

A tip for users of the Diamond Tool Holder that want to grind a tip for thread cutting, use HSS for this operation instead of Crobalt as I've found it's a bit more brittle and tends to chip easily with the small point on heavy cuts.

Crobalt, like carbide and HSS, has its pros and cons. Some operations such as turning stainless it excels at, and some such as thread cutting it is not so suitable for.

Gary

Hi Guys

As Michael says, Crobalt is a cast alloy containing 50% cobalt, the other half is made up of tungsten and chromium, it has no iron or steel in it.
Crobalt comes into its own when used on tougher materials such as cast iron and stainless steel, it will work fine on any other materials that you would normally use HSS for but will withstand much higher working temperatures. Coolant is not usually needed unless to improve surface finish.

If you are just doing light turning of mild steel or brass, Crobalt will give the same sort of results as M42 HSS, although the cutting edge will normally last longer on the Crobalt, that's why it was used on repetition lathes in preference to HSS until carbide took over.

There is a video on the Eccentric Engineering website showing a test between Crobalt and a premium brand M42 HSS. The test was done on 304 stainless, and cast iron, the results were pretty emphatic.
The video is on the Crobalt information page, just click the orange Eccentric Engineering ad on the right hand side of this page if you want to have a look.

Crobalt also have an information page here www.crobaltusa.com/index.htm

Cheers

Gary
Eccentric Engineering

Hi Andrew

I've been using the Haimer 3D Tastic for a while now, best bit of measuring gear I've ever bought.

I only have manual mills with DRO and got sick of using a combination of edge finders, coax indicators, and dial indicators, to locate edges, hole centres, align the vice and table etc etc. Since I got the Haimer I've not used anything else, just pop it in the collet chuck and it'll do the lot.
I use the vertical movement to reset the swivel table square, or the top of a job in the vice, something a touch probe wouldn't be good at.
It's also useful not having to subtract half the radius of the probe each time.

I got the New Generation one because of the bigger 50mm dial and it's only 4mm longer than the Zero Master Analog
**LINK**

Cheers Gary

Hi All

Yes I did recieve the relayed email from Eric/Don, thanks for that.
Getting a bit late in Oz but I thought it easiest to just send a reply straight here.

There is a warning not to use the upside down holder on lathes with a threaded nose, it's on the product description in the shop section of the website, just above the buy it now tabs. I've also put a warning on the magazine ad and the email flyer that I've sent to previous customers. I thought that would be enough but I'll add one to the information page as well, just to make sure.

As to whether they work or not, all I can say is I've used mine every working day for the last five years, I've never had a jam, I'm still using the same blade, and it's only about 1/4" shorter now than it was five years ago (it's the same one that's in the video). The only slight inconvenience I've found with the BTF holder is having to stop the lathe and put it into reverse.

When I was still in the workforce I saw plenty of crashes in the workshop with a indexable tip parting tool (Sandvik), a couple of the crashes were mine . I just find the upside down tool is more forgiving.

Disclaimer : I have no connection with this business other than as a satisfied owner .

Upside down parting tools may not suit everyones circumstances, but here's a note I recieved a few weeks ago from a customer who'd just bought a second one.

I was so impressed with the BTF toolholder I showed a friend. He wanted one as soon as I showed him a sample of what it could do. I have a Colchester Student lathe but have never been able to part off using any of the standard parting tools. I was able to part off 30mm Al alloy and 25mm mild steel without any issues. Brilliant! LH diamond toolholder is a good addition as well.
Mark from Queensland.

Cheers all
Gary
Eccentric Engineering

I was so impressed with the BTF toolholder I showed a friend. He wanted one as soon as I showed him a sample of what it could do. I have a Colchester Student lathe but have never been able to part off using any of the standard parting tools. I was able to part off 30mm Al. alloy and 25mm mild steel without any issues. Brilliant! LH diamond toolholder is a good addition as well.

Edited By Eccentric Engineer on 09/11/2009 03:38:24

Edited By Eccentric Engineer on 09/11/2009 03:39:56