Re: Anyone try a Shars fully machined backing plate and chuck?

Curt Wuollet <wideopen1@...>

6 holes and I can tell by inspection,  it's not balanced. Actually there are 8 as there are a couple small threaded but not countersunk holes opposite each other. The way they did it it has 5 holes on one side and 1 hole on the other, ignoring the small symmetrical holes. Perhaps that's why the 3000 RPM rating, that's the speed where it chases you around the room. A holes worth is small compared to the combined mass, but what were they thinking?



On 09/11/2014 02:54 AM, Edward Draper eddie.draper@... [SOUTHBENDLATHE] wrote:
The answer to your question about whether the 3 plus 4 hole attachment affects balance:
If there are 2 entirely separate sets of holes, 7 in total, it won't, because each set is balanced within itself regardless of how the 2 seta are phased relative to each other.  The trouble starts if they share a single hole at any point, i.e. only 6 in total.  You'd have one hole's worth too much metal at that position.  I'd be interested to know which you have, and if the latter, an enquiry to the supplier might reveal whether they have taken any compensatory steps. like removing further metal adjacent or adding some opposite.

From: "Curt Wuollet wideopen1@... [SOUTHBENDLATHE]"
Sent: Thursday, September 11, 2014 2:13 AM
Subject: Re: [SOUTHBENDLATHE] Anyone try a Shars fully machined backing plate and chuck?
Back on topic, the chuck and backing plate showed up today. When I got home the screen door was hanging open because the mailman left the package there. Kinda stuffed into a flat rate box with much tape and even a band to hold it. Rounded up my old F20 camera and took a picture of the freshly opened boxes. It's got that "new chuck" smell. Nothing looks attractive in oiled plastic bags, so I grabbed some paper towels and proceeded to unwrap. Looks really good, just like the picture on Ebay.Big ol chunk of dense cast iron, finished well, no visible voids, all bearing surfaces ground and flat. I cranked out the outside jaws and cranked in the inside jaws. Both sets are very closely fitted, no play in the slots and just clearance in and out. Moves smoothly. Only one defect, the cross handle for the key is loose. The backing plate is drilled for both 3 and 4 bolt patterns (I wonder how this affects balance?) and is machined on all surfaces. Of course, I had to go see if it would screw on the spindle. Nicely threaded and went right on, meaning the register is probably too large, I'll get dimensions later. Snugged it up against the shoulder and swung the indicator on it.  About .5 thousandths axial and 7 thousandths radial. So you could actually just turn the step and bolt the chuck on and you wouldn't be too far off.You would only be using 3 or 4 threads, but you could do it. My bearing/spacer hasn't arrived yet and I don't have too much time tonight, So I'll probably go look at the motor issue. No buyers remorse yet.RegardscwwOn 09/09/2014 06:15 PM, Curt Wuollet wideopen1@... [SOUTHBENDLATHE] wrote:

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