Tangential Tool Holder

[FarFar]

Hello Bill

You are of course rigth, but I was so disappointed that I cut it up.
This gave the possibility to see the formed channels under magnification and they are better than any mashining process.
The sensible way will be to make a new holder as close to final form as possible,still allowing squezing and then make a forming tool smaller than intended tool.
In my case instead of 4.76 mmsquare (3/16) go to a grinder and make a 4.26 mm square pressing tool as springback was .5 mm.
Use a good HSS because Crobalt is non-magnetic and not easy to fix on a surface grinder.

 

[FarFar]

Hello Erik

I am sorry for Your wife,children and You.
The 5 inch 3 jaw chuck of indian manufacture, I have ,is accurate within .02mm and in special cases I have used kitchen aluminium foil and seen less than 0.01 mm.
This means I willbe glad to receive your surplus Boxford backplate ,but do not know what to do with the Pratt and Burnerd thing.But thank You for the offer.
If You care to measure the distance accurately from top of compound slide to lathe centerline on Your chipmaster I can make a TanTool holder design for interested peoples.
Kind regards and I will mail my postal adress

Niels

 

[OrangeAlpine]

Niels, starting to give the toolholder some serious thought and wondering just how large it should be. My lathe is a 12" Asian model with a 4 way tool post, which I will remove as use of the 4 way allows only 1/2" tall tool holder. The hold down bolt is 16MM, how large do you recommend?

Bill

 

[FarFar]

Hello Bill

Nice that You are considering comming into the magic circle.
First decission is how wide is the widest swarf You comfortably want make on Your lathe.This is a very important question as the usual bigger is safer is not true.
The time for regrinding a 1/2 inch toolbitt is seven times as long as for my favourite 3/16 Crobalt suitable on my 9 inch Southbend improvement .
1/4 inch is rigth for 12 inch lathe I would say.
Next question is what exact distance do You have from tool mounting surface to lathe centerline.The simple way is to know is turn something and put feeler gauge blades under until contact .Half the diameter plus total amount of feeler gauges is what we are after.
Do us a favour and remove your four tool thing and send us all a photo of the combat area.
It will be a pleasure for an old teacher to help You design a tool that I would not be without.

 

[OrangeAlpine]

Niels, thanks for the welcome. I've been a member of the magic circle for a long time, having purchased a Diamond over ten years ago. I use it about 99% of the time. However, I want something better. Something that will cut in both directions and if possible, is more ridgid. So here I am!

Here is the requested photo. Mounting surface to centerline is 1.055". The "collar" on the tool post bolt measures .942" and is a part of the bolt. The bolt is 16mm. I am going to have to replace the entire hold down system.



Bill

 

[FarFar]

Hello Bill

Nice picture and we are almost there.
Please go to start of thread, second picture and estimate minimum distance from cutting point to centre of the 16 mm holding down bolt.
Do You have a milling machine?

regards

Niels

 

[OrangeAlpine]

Minimum distance, 3". Yes, I have a milling machine. Making the new holddown will not be a problem.

Bill

 

[FarFar]

Hello Bill

Let us repeat (in metrics,I am to old to learn imperial)

Tool bit 1/4 inch Bolting down hole 1/2 inch

Main block 28 mm high and 35 mm wide and plus 100 long.One end sawed 15 degree.
Wedge piece sawed free
Both pieces put on milling machine and mill future tool bit channel
Put a really sharp cornered toolbit between and give a sligth spress squeze one or two tons.
This is to make sure that corners are sharp and angles correct
Drill and tap and freebore for balancing screw (I recomend 5 mm) and pulling together screw (8 mm?)

I would recommend to mockupping in plastic,wood or aluminium.

More to follow and kind regards

 

[OrangeAlpine]

Thanks Niels. First up will be making the new hold down assembly. I think I will "make it right" and center all future tooling around it.

Bill

 

[FarFar]

Hello Bill

Very wise and a 1/2 inch rod or bolt is more than enough.It is better to harm the bolt than then channel in compound slide.
The tool shown is very easy to make and fast to use.
For tangential tools I feel that the expensive to make round pull in bolt version is best.
Somewhere on web there is a man demonstrating very basic spark erosion,but I cannot find it.
Please help if You know where