[atlas_craftsman] Re: Quick Change Tool Post
- Like the others, I would likely be interested. I have a 6" lathe. Would
yours fit this? Also, a picture and/or description would be helpful (as
well as an estimated price!!). Also, what size tool would it take.
----- Original Message -----
From: Ted <tburford@...>
Sent: Tuesday, May 11, 1999 9:56 AM
Subject: [atlas_craftsman] Quick Change Tool Post
> I plan on making some "Quick Change Tool Posts" Is there a market for
> them in this Atlas / Craftsman Lathe group?
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- Ok, this sounds good but I don't see how pinching the lips of the cast iron
compound can do much harm to them. I know they can break in a crash but it
doesn't seem possible by just pinching them between the bolt and the tool
On Tue, Feb 28, 2012 at 11:25 AM, James Irwin <jirwin1@...> wrote:
> You make a lot of assertions that run contrary to the mechanics & strength
> of materials course work I had getting my BS degree.
> The bolt will not break first, but the threads of the bolt completely
> (cut in half) the section between the sides of the slot. Therefore, there
> no flexural stiffness added by it�s presence.
> My thought to braze the joint makes one piece of steel out of the bolt and
> T-nut; to the extent of the tensile strength of the braze to steel joint,
> I�m be more concerned about failure of the top lips of the cast iron
> compound slot than any of the bolt or nut parts. Therefore spreading the
> load over a larger area makes good sense.
> Jim I
> On 2/27/12 9:51 PM, "wa5cab@..." wrote:
> > That isn't exactly correct. In the first (elementary) analysis, the wings
> > of the inverted T-nut are in shear. And the longer they are, the higher
> > force requred to shear them off. Plus the longer the T-nut, the stiffer
> > is. The vertical section of the T that's in the slot contributes more to
> > this stiffness than do the wings (at least with typical T-nut
> > And the longer the T-nut, the smaller the angle it can rotate through.
> > the higher the friction force resisting that rotation. And the higher the
> > total force that would be required to break the top out of the compound.
> > Bottom line is that with a full length T-nut, the component that will
> fail is
> > the bolt, usually at or near the head.
> > Also, to comment on an earlier post, it does not matter whether the bolt
> > threads are coarse or fine. UNF and UNC threads have very close to the
> > shear cross-section per linear inch.
> > In a message dated 02/27/2012 18:03:34 PM Central Standard Time,
> > jirwin1@... <mailto:jirwin1%40austin.rr.com> writes:
> >> > I am more than a little convinced that the only part of the T-nut that
> >> > really bears against the compound surface is that near the bolt. I.e.
> >> > rest is just �along for the ride� as it were. Having the whole
> slot(?) in
> >> > the compound filled with steel makes us feel good, but does little to
> >> > improve strength. Not that it probably really matters, I suppose.
> >> >
> >> > Bottom line is that a 1 inch long (or maybe less) T-nut will do
> >> > a
> >> > full length one will.
> >> >
> >> > Better would be a spring steel T-nut that has a curve calculated so
> >> > tightening it down would truly spread the load along the length of the
> >> > slot
> >> > in the compound. The T-section is intrinsically pretty stiff, but all
> >> > effect
> >> > of the upright center section (beyond simply guiding the nut in the
> >> > which the bolt does quite well anyway) is wasted material.
> >> >
> >> > Jim
> >> >
> > Robert Downs - Houston
> > wa5cab dot com (Web Store)
> > MVPA 9480
> > [Non-text portions of this message have been removed]
> [Non-text portions of this message have been removed]
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