Angled HSS toolholder and tool sharpening angles

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Angled HSS toolholder and tool sharpening angles

This topic has 8 replies, 6 voices, and was last updated 19 September 2010 at 20:50 by Billy Mills.

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17 September 2010 at 20:51 #5188
Frank Small
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@franksmall87776
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17 September 2010 at 20:51 #55812
Frank Small
Participant
@franksmall87776
Hi Guys

I have been using carbide tipped tools but in the search of a better finish I am going to try HSS.

The HSS holders I have are angeled up about 20 degrees from the horizontal. Is this a standard tool holder?

Is all the standard published sharpening data re angles etc related to a horizontal or angeled tool holder.

Assuming that my tool holders are non standard can someone suggest

sharpening data and any other ‘work arounds’

Thank you for your interest

Regards

Frank
18 September 2010 at 07:12 #55830
John Olsen
Participant
@johnolsen79199
The angled holders like that are giving you a built in top rake, ideal for steel. This is common on lathe tool holders since it saves grinding a top rake onto the tool, which over a few sharpenings saves you a lot of HSS.. The front still needs clearance, about five degrees typically, and that is relative to the vertical, not to the top face. For brass you don’t really need any top rake.

regards

John
18 September 2010 at 09:20 #55835
Frank Small
Participant
@franksmall87776
Hi John,

Many thanks for clearing up my understanding of sharpening HSS tools

From what you say I assume the normal published data is for horizontal tool holders and needs adjustment to accomodate the tilt on the tool.

Regards

Frank
18 September 2010 at 13:03 #55841
Clive Foster
Participant
@clivefoster55965
Frank

20 degrees being pretty much the maximum top rake you will ever need you just flatten off as required to get the right one for the job. It may help to think of the bottom surface of the tool-holder as your zero rake reference.

One oft overlooked advantage of tool-bit holders is that they make a good “poor boys” Quick Change system substitute as reference to a tool height gauge when changing bits also sets the projection to pretty close limits. If you fancy trying this best way is to use a slim single slot block type mount, fabricated construction is OK if you don’t fancy heavy milling, and arrange some way of gauging the tool tip height off the top of the mount. The job in progress tends to get in the way of the usual sort of gauge. Use the bent to the right holder, if you have one, for all normal work as it lets you get closer in to the chuck than the straight one without worrying about clonking the saddle. Bent to the left for facing work. Set the business end at 90 degrees to the bed for normal turning and parallel to it for facing.

All the angles go on the tool so they can easily be replicated using simple templates or a SouthBend style holder if you feel fancy. I feel that a major reason for finish problems encountered by inexperienced workers is the inability to exactly reproduce the tool shape. Slight shape changes when grinding usually mean that the tool needs to be handled a bit differently for best results.

Clive
18 September 2010 at 14:17 #55846
Dusty
Participant
@dusty
These tool holders are best used in a ‘boat type’ tool post. This allows the top rake and tool height to be adjusted farly simply by rocking the tool on the ‘boat’ before tightening the clamp bolt. the other adcantage of this type of tool holder is economy of tool steel. generally they use smaller section tool steel and you can use up to the last half inch or 12mm if you prefer.
19 September 2010 at 11:08 #55900
Frank Small
Participant
@franksmall87776
Hi Guys,
Many thanks for your assistance which is very reassuring when information is otherwise limited.
The results I am now achieving are certainly as good as the carbide tips
I suspect I could improve that by creating that radius on the tip. I tried using the grinder but it seems too course.Maybe I will try a stone
I will summerise my approach to tool and tool height to date. It is only my approach but may be helpful to others. I used to set and measure tool height with a digital vernier but of course it was a hit and miss affair. I was also using carbidre tips. In the search for a

better finish I decided to use HSS cutters. I then decided to get serious, measuring tool height accuratly guided by article in MEW
1. Turn a shaft to any diameter
2. Measure and divide by 2
3. Using block and feeler gauge measure height to lower edge of shaft
4. Add two results to give tool height.

Obtain a block of steel that will stand vertically on saddle and exceeding the tool height by perhaps 10mm
Machine a slot to mark the tool height from saddle. This is the tool for setting cutter height.
The tools in the angeled HSS holders can now be adjusted in out to set correct tool height as suggested in the forum
Carbide holders can be machined to correct tool height. Something I was reluctant to do until I was sure of the exact height.

Now to gringing the HSS base on my understanding of the help I received on the forum
No need to grind a “back rake angle” as this is provided by the tilt of the tool holder. However there is a need to have a side rake angle
The profile of the tool as presented to the workpiece should be the same as that in the many well publisied article.

Regards

Frank
19 September 2010 at 12:23 #55907
Ian S C
Participant
@iansc
When I first got my lathe setting the tool hight was a bit of a puzzle, so I took my 6″ square, and stood it on the saddle, then I scribed a line across the blade with the hard center in the tail stock, I’v been using that ever since. There are better ways I imagine, but that suits me. Ian S C
19 September 2010 at 20:50 #55929
Billy Mills
Participant
@billymills
Frank,

Next time you face off anything in your lathe, the centre pip is more exact than several measurements added because it is the real thing!, when you have exact centre height the top tip of the tool will be right through that pip, slightly too low and you will get a minute pip.

The finish you get is down to the finish of the tool edge, rough grinding -lots of scratches that will be partly reproduced in the job because only the high spots leave a lasting impression.Try stoning the edge and compairing the difference.

Regards,

Alan.
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