Small sine plate

[steamer]

Done!

The rolls are unhardened 1144SP turn, ground, polished stock. From the same piece 1 right next to the other.

The top is parallel to the rolls to about .0003" left to right and a bit better the long way. I call it a win!

I'll make a nice box for it.

I intend to use in in the Kurt vice. I'll need to make some fences for the front and side...but that's kinda trivial.

Dave

 

[arnoldb]

Thm:

Regards, Arnold

 

[steamer]

Thanks for the comments and support Arnold!

Dave

 

[Bolster]

It's a pleasure to look at, I'm sure it's a joy to use! Congrats :bow:

 

[steamer]

Thanks bolster!

Dave

 

[bezalel2000]

Dave

Thanks for the link to get here - Well worth the trip.

I have had in mind to make some thing like this for a while and now I know what the finished item looks like :bow:

I was thinking a little about the precision error issue and thought that you could shim one of the faces between the round bars with a feeler gauge leaf.
This would effectively increase the length of the hypotenuse which would be a much more sensitive adjustment at lower angles.

What do you think?



Oh and of course thanks for the post itself.

Bez

 

[steamer]

Thanks for the kind comments and interest Bez!

I'm sure that your approach would work. You could also try scraping it in....I did, and I found it easy to take a few tenths off here and there to get it where it is. It really is amazing how controlable it is as a process.

Dave

 

[steamer]

I'll see if I can't sketch this thing up ....Give me some time

Dave

 

[bezalel2000]

Hi Dave

(scraping {if I was brave enough to give it a go} is of course a one way trip - hard to put back and would only fix the error at a single angle)

When I mentioned the feeler gauge thing I was thinking of the case where the stack of gauges under the sine bar doesn't bring you too the exact angle required.

eg. if you were looking for an angle somewhere near 30 deg and your stack of gauges was half a thou more than required.

by adding 1 thou to the hypotenuse with a shim you could reduce the half thou error closer to zero.
at around 14 degrees 2 thou on the hypotenuse to correct a half thou error on the stack (sin 14.5* = 0.25)
at 6 degrees 5 thou etc. (sin 6* = 0.1)

Am I making any sense?

Baez

 

[steamer]

Yes it is a metal removal process...However...at a very slow rate

If I "Double Cut" during rough scraping, and I LEAN on the scraper...I MIGHT take off .0005" material..and I have to sharpen the tool after every cycle! If you doing light scraping, it is usually less than .0001" per pass....

If you don't believe me, try it for your self on a scrap piece of iron... You'll be amazed...really!

If it doesn't work, through the piece of stock back in the lucky box!

;D

Dave

 

[bezalel2000]

Some of the stuff in my old stock box will need more than 2 thou just to make it shine :big:

 

[steamer]

You'll never know until you try... ;D

Dave

 

[dmac]

Question,

What do you use a sine plate for and how.

Dave.

 

[bezalel2000]

What do you use a sine plate for and how.

If you need to machine a surface at at precise angle with respect to another surface set the plate to the required angle (just like a sine bar) then bolt the job to the sine plate.

Rests the curved surface of one of the round bars on the milling table. The other round bar is lifted by a collection of gauge blocks to a precise height.

when all is secure start milling. ;D

Bez

 

[Lew Hartswick]

when all is secure start milling. ;D

Bez

That bit "when is all is secure" sometimes can be the trick.
Clamping the sine plate to the table with it aligned to an axis.
...lew...

 

[steamer]

Ah yes, this is true Les, however, I intend to use mine in my Kurt vice, clamping from the sides, for most of my milling use.

I may co-bore the pins so that I can strap it from the sides otherwise....have'nt decided yet...easy to do if I need to.

Dave

 

[Tin Falcon]

What do you use a sine plate for and how.

Sine bars and sine plates are uses in conjunction with Gage blocks to set the height of one end of the bar or plate and hence set the angle. the length of the sine bar is typically 5 or ten inches long.
Tin