Re: [CAD_CAM_EDM_DRO] Re: Sherline CNC Conversion is Complete (almost)

I will give you as many details as possible.

The mill was a Sherline Model 5000, bought new off of ebay for $350.00 (hell
of a deal). The guy selling it is a Sherline dealer and he screwed up his
auction listing and forgot to put the reserve price in. He stood by the
deal and had Sherline drop ship me the mill. It arrived and happened to be
the CNC-ready version of this mill. This was a problem since there is no
way to use the mill manually without double shafted stepper motors attached.
I called Sherline and they told me I could return the mill for a replacement
or just keep it and it would be their mistake. I kept it and made some
brackets to support the manual handwheels.

Since I had the Sherline motor mounts I decided to build my own CNC. I
solicited information from this list and the Sherline group list. I got
some very good advice. I bought the Camtronics 3-axis 2 Amp stepper driver
kit and assembled it (took me about 4 hours). I bought 3 160 oz-in double
shaft stepper motors from Dan at Camtronics. I bought a 15V 10 amp power
supply off of eBay for $20.50. I download TurboCNC from Dave Kowalczyk and
that controls my stepper motors. I have the x-axis moving from right to
left, the z-axis moves up and down, and the y-axis is connected to a
Sherline CNC-ready rotary table. I do not have the linear front-back
milling axis attached to a stepper motor yet.

I write the G-code by hand using Microsoft Excel to generate digitized
points for curves as long as I know the functional relationship between X
and Y. So far, I am cutting mathematical functions around the rings so this
is easy to generate. I have been using 720 point resolution around the 360
degrees of the ring. I have to trace each curve about 5 times to achieve
the final depth. I am taking 0.0075" cuts with a 0.040" solid carbide
4-flute endmill. I run the endmill at 2800 RPM, but I just bought
Sherline's new pulley system to increase the spindle speed to a max of
10,000 RPM.

I have no idea what my stepper motor feed rates are. I have only cut three
rings so far, as I have been SLAMMED with orders for non-CNC requiring
rings. I set the machine up to cut VERY slowly the first time, but I sped
things up the last time and I traced a 5 period sine wave around the ring
five times in 19 minutes 27 seconds. This is plenty fast enough for me
right now.

There is no trick to cutting titanium except to take your time. The cutters
that I am using will break long before the Sherline machine flexes due to
the hardness of the titanium. I have used my Sherline lathe everyday for 2
years, and all I have ever cut with it is grade-5 titanium, and it seems to
be holding up remarkably well. And at the price for a new lathe, they are
almost disposable.

You can view a picture of two of the CNC cut rings at the following link.

http://members.rennlist.com/statmandesigns/sinewavecomparison.jpg

The ring on the left has been inlaid with fine silver and the one on the
right was inlaid yesterday with 18K yellow gold.

Daniel J. Statman, Statman Designs
www.statmandesigns.com

----- Original Message -----
From: <luisguillermo98@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, October 15, 2001 11:37 AM
Subject: [CAD_CAM_EDM_DRO] Re: Sherline CNC Conversion is Complete (almost)


> Where Did you buy your cnc system?
> have you try to cut your titanium or stainlees with the sherline?
> what was the feed speed you use? give some details please...
>
>
> thanks
>
>
>
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