Looking for cutting needles to copy

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evildrome
Posts: 59
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Looking for cutting needles to copy

Post: # 47681Unread post evildrome
Thu Aug 31, 2017 9:17 am

Hi All,

Long story short... I'm a tool maker (for a hobby). I like making small precise things and buying old precise machines.

I was approached by an Italian guy who asked me to make some record cutting needles in tungsten carbide for him.

Right up my street. Anyway, he has pulled apart his machine and it will be apart for some time so no fun for me.

I want to have a go at making some cutting needles. I have made some (what I think) are Rek-o-Kut needles?

1/16th x 1/2 with a 45 degree spade type point.

If you've got a worn needle you want copied, let me know. There will be no charge.

Wilson@wilsonlogan.com

BTW I'm in the UK.


Cheers,

Wilson.

+44 7711 026653

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tragwag
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Location: Providence, RI USA
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Re: Looking for cutting needles to copy

Post: # 47685Unread post tragwag
Thu Aug 31, 2017 12:35 pm

interesting! just metal or sapphire/ruby as well?
making lathe cuts on a Presto 6N, HIFI stereo cuts on vinylrecorder
at Audio Geography Studios, Providence, RI USA
http://www.audiogeography.com

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jjwharris
Posts: 189
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Re: Looking for cutting needles to copy

Post: # 47686Unread post jjwharris
Thu Aug 31, 2017 4:39 pm

Have you got any photos? I'm sure there will be a lot of people here interested in this!
Record Lathe Embossing Supplies - http://www.supplies.johnnyelectric.co.nz/

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evildrome
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Re: Looking for cutting needles to copy

Post: # 47727Unread post evildrome
Mon Sep 04, 2017 9:19 am

Just tungsten carbide.

I could do sapphire as well but I don't know where to get the blanks.

I only have a crappy out of focus photo...
carbide-needle.JPG
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markrob
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Location: Philadelphia Area

Re: Looking for cutting needles to copy

Post: # 47729Unread post markrob
Mon Sep 04, 2017 11:08 am

Hi,

Looks like a nice job, however the back angle does not seem right. Do you have a drawing of a cutting stylus? If not, PM me with your email and I'll send one along. Also, I'm not sure tungsten Carbide can hold a keen enough edge. Have you had anybody try to cut using this stylus? HSS seemed to do better back when I was playing with this. Are you grinding/faceting to a mirror finish?

Here is a source for sapphire rod stock:

http://www.swissjewel.com/2/rods/

Mark

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evildrome
Posts: 59
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Re: Looking for cutting needles to copy

Post: # 47741Unread post evildrome
Tue Sep 05, 2017 7:58 am

Hi Mark,

I used this drawing:

Image

Basically the front face is 90 degrees.

Its cut on a 1200 grit diamond wheel so its a high (if not "mirror") polish.

I agree that HSS takes a better edge. I didn't have any HHS rod at 1/16" diameter so I went with Tungsten Carbide, which, to be fair, will hold an edge longer.

What kind of money is in the sapphire rod stock e.g. the SP-21 (1/16") ? The site is a bit cagey about pricing (call for a quote!) which is never a good sign...

Cheers,

Wilson.

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markrob
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Location: Philadelphia Area

Re: Looking for cutting needles to copy

Post: # 47742Unread post markrob
Tue Sep 05, 2017 8:31 am

Hi,

I was using diamond lapping compound charged on an aluminum lap to finish to a mirror. I used a simple home made template faceter to produce my angles. Not sure if 1200 is good enough. You will need to test. I did worry about the burnishing facets. As the stylus dulls, you sort of get them for free. They do help lower noise in conjunction with heating the stylus at the expense of a bit of high frequency loss.

The diagram you have is correct, but its not too detailed on angles. It looked to me like your stylus did not have the back angle. The stylus should end it a single point tip that comes in contact with he record surface. Maybe your stylus does, I can't quite tell from the photo.

I got some samples of the sapphire rod from Swiss Jewel when I was playing around. It helped that there was a sales outlet very near my location and I had a rep drop them off at my house on the way home from work. From what I remember, the cost is not too bad. I bonded the rod to an 1/16" diameter aluminum shank with the mounting flat ground in.

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evildrome
Posts: 59
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Re: Looking for cutting needles to copy

Post: # 47762Unread post evildrome
Wed Sep 06, 2017 4:08 pm

My needle does have adequate back angles.

I have been cutting metal on lathes for 20 years. I may not know about records but I know about chip formation, screw cutting and rake angles :)

What I do not have is a tip radius or burnishing facets.

I am working on a new rotating fixture that will produce the tip radius but the burnishing facets will need some thought...

I have enquired about HHS rod and its seems available cheaply in the USA (but not the UK!). I can buy 3ft for $7 or two inches for £5.

Bah!

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markrob
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Location: Philadelphia Area

Re: Looking for cutting needles to copy

Post: # 47763Unread post markrob
Wed Sep 06, 2017 8:21 pm

Hi,

Sorry. I was just trying to be helpful. I'll keep my two cents out of this. Good luck with your project.

Bah Bah!

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evildrome
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Re: Looking for cutting needles to copy

Post: # 47769Unread post evildrome
Thu Sep 07, 2017 8:49 am

Sorry Mark,

I didn't mean to take umbrage. I value your advice, deeply.

I learned long ago to heed the advice of experts.

I apologise if my tone came over as high handed.

Cheers,

Wilson.

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handcut
Posts: 252
Joined: Thu Oct 16, 2014 5:41 pm

Re: Looking for cutting needles to copy

Post: # 47771Unread post handcut
Thu Sep 07, 2017 1:23 pm

Hello Wilson,

There's a couple of good books with a fair bit of info on stylus construction, including tip radii. One is an AES anthology: Disk Recording Volume 1. It's still in print. The other is: Sound Recording and Reproduction by Oliver Read (not that one). It's out of print and is available as a PDF somewhere on t'interweb. Both fantastic resources. It may also be worth mining the BBC tech archives. You'll be building cutterheads and lathe components before you know it!

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jjwharris
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Re: Looking for cutting needles to copy

Post: # 47806Unread post jjwharris
Tue Sep 12, 2017 7:23 am

Hey Wilson,

Just sent you a message on eBay, have these been tested?
Record Lathe Embossing Supplies - http://www.supplies.johnnyelectric.co.nz/

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evildrome
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Re: Looking for cutting needles to copy

Post: # 47812Unread post evildrome
Wed Sep 13, 2017 6:10 am

Maybe.

There's a studio in Ireland that I sent a couple to a fortnight ago but I know they're in the middle of moving and I've not heard back from them yet.

I'm happy to send you a couple.

PM me.

Cheers,

Wilson.

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