turning chisel angles

[hawkeyefxr]

As mentioned in my acrylics post.

I treated myself to two new skews, one was the normal flat section type the other an oval skew. These were sharpened to a very acute angle which for me is to sharp for acrylic, at the moment they oil and wrapped up.
The skew that i got with my lathe is a much 'blunter' but cuts beautifully, the acrylic just gently slides off, i think this angle is about 55 to 65 degrees., if that makes sense.
To me while the acute angle is very sharp for acrylic it is to sharp, also if i were to use it it's edge would be lost quite quickly. My 'blunt' looking one lasts very well.

I have seen a wide range of angles at various websites but i am thinking that for acrylic they are different.
Also does the same apply to gouges as to the angles i have mentioned.

For the initial cuts of the acrylic i have made a carbide tipped tool which is perfect for me to knock the corners off the square blanks, This works well till it approaches the round section when it becomes harder to get a cut without digging into the blank.

I have seen names given to the different cutting angles but not the actual angle.

I have a Tormek wet stone that i have had for a few years now.

 

[bassethound]

For me what I do is take no set ways to sharpen angles and just do em to what find is best for me, you soon find out the best ones with practice! just me of course..

 

[Penpal]

I round off the acrylics a bit on the sander, I still far and away understand timber or am more comfortable with wood. Certainly every chisel I have I need to find the best angle. The variations in steel is amazing.

Peter.

 

[spik3y27]

First time, I find the blunter the tool the better cut I get on my own cast resin. The chipping out on hard acrylic is a pain but due to the warmer weather of late my castings are staying softer longer and the streaming off is much better for me with less angle.

Sent from my GT-I9300 using Tapatalk

 

[EStreet]

Few things to note on chisel angle. It makes a difference in how long the chisel will stay sharp with any given material.

General Rule of thumb:
The sharper than angle the more you will have to sharpen the chisel as it will DULL faster.

That being said, a sharp angle on HARD/DENSE material will dull the chisel super fast. A BLUNT angle on SOFT-MEDIUM material the chisel will stay sharp longer.

Tool steel matters greatly in this ratio trade off as well. The



Now lets talk about 'quality of cut'. Hands down a sharp angle that cuts super fast, aggressive will provide a cleaner higher quality cut than a blunt angle chisel.


As for angles vs materials goes there is another problem that compounds this greatly, that is the TYPE of cut you do with the chisel. I.E. Skew chisels has 8 type of cuts you can make and each one will have an 'optimal' angle and they need not all be the same angle. From this you can take 8 skew chisels with optional bevel angles with the same type of tool steel and you can very quickly see which one works best for clean cuts and rough cuts. Also your tool height plays a major factor in this as well.

Hope this helps.

 

[EStreet]

Some sites you can look at for more technical in depth on the skew.


Skews Part 1

Also this is an HOUR long video at youtube. It is *WELL* worth the watch.
The Skew Chisel with Allan Batty - Full Length Video - YouTube


p.s. note for the moderators. There is no 'commercial links' in the links I have posted, that I am aware of. I have posted in good faith full technical details that will enhance skill levels and not 'commercial links'

 

[Buckeye]

p.s. note for the moderators. There is no 'commercial links' in the links I have posted, that I am aware of. I have posted in good faith full technical details that will enhance skill levels and not 'commercial links'

There is no need for you to tell us there are no commercial links, we are able to determine if they are commercial or not.

Peter

 

[Penpal]

I accept help from wherever and whenever I do remember clearly when Timberbits pioneered the videos on how to for many subjects and now this is done by so many firms. Now U tube abounds with references to woodwork. In house many members have given us so much in the way of video demos. Thank you Ed for your contributions they are so welcome. I look forward to them.

Peter.

 

[fortress]

Hello Steve, looks like you've been lurking on the side lines too, welcome sir let's see what you've got.

 

[Bill Mooney]

The skew I use on acrylic is sharpened 65ish degrees across the 2 bevels & it works for me. From what you say about your carbide tool I get the impression you are not cutting on centre. Check this be placing your tool against the point of your tailstock drive with the tool level on the tool rest. The top of the carbide tip should be dead on centre. It's worth checking. I have a locking collar on my tool post which I set to the proper height then if you adjust your tool rest the height stays the same.

 

[hawkeyefxr]

Thanks for the reply, just about every answer is to my way of thinking. Regarding the carbide tipped tool i cut below the centre line, the actual tip is flat with no rake on it so i would say it scrapes rather than cut. I have just ordered some more that do have a rake all be it very small.
For my new chisels i will reduce the angle across the two faces in small amounts so i do not grind off 1 inch of valuable chisel for no reason. I did see mention an angle of 55 to 65 degres.

 

[Woody]

There are a thousand different ways and opinions on angles presentation and to each individual they are all right I find the best way to do anything is the way that comes naturally to you as an individual by the time you have listened to every opinion you will be more confused than when you started

 

[EStreet]

On every skew there are two (well technically 3) angles.

 

[Penpal]

Many years ago a mate at my club said in reply to my comment on the royal skew was come over to my place one day. He said first up on that day I went do you dance (help I thought why did I bother) then he proceeded to show me how to use my body to move with the skew to achieve safe angles a beautiful shapes and yes in a hour I was quite proficient.

Like most christians I soon lapsed and went back to my own way, enjoying the skew again and having fun. Stuart in the video sure has the instrument mastered as does Richard Raffan I have observed for hours.

There is pure poetry in motion with skill, thanks Ed for bothering.

Peter.

 

[wm460]

Interesting Video, thanks for posting.

 

[hawkeyefxr]

There are a thousand different ways and opinions on angles presentation and to each individual they are all right I find the best way to do anything is the way that comes naturally to you as an individual by the time you have listened to every opinion you will be more confused than when you started

I like you views they lean to my way of thinking.