Re: [Emc-users] Sewing Machine Stiffness

[John Dammeyer]

One of the continuing discussions on the Gingery "Make your own shop from 
scrap" forums were the lightness of aluminum castings and how that made them 
more susceptible to vibration.  That's the biggest fault in my Gingery Lathe.  
I did cut some steel stock intending to create a stronger bed frame (filled 
with concrete) but then the South Bend Heavy 10L arrived and the Gingery is 
rarely used.  

My feelings using epoxy and fibreglass is that it will suffer the same issues.  
OTOH, epoxy with granite filler has been used.  But still in frames that by 
themselves are already strong.  Perhaps a mix of glass fibre and granite would 
be the best.
John


-Original Message-
From: BRIAN GLACKIN [mailto:glackin.br...@gmail.com] 
Sent: May 21, 2023 3:54 PM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Sewing Machine Stiffness

Epoxy is a bonding agent
Fiber (glass or otherwise) add cross linking in the resulting matrix.

Thes two Used alone, the resulting composite will be weak.

You need sized aggregate to make a much more rigid and robust structure.
The epoxy is then strongest bonding all these parts together

Sand and fines to fill the spaces between larger aggregate.   The top size
of the aggregate will depend on the thinnest portion of the structure but
generally 13-19 mm max.

During ww2 they made lathes bodies out of concrete with imbedded steel
parts that were jigged in form or line bored for the spindle and tail
stock.

https://www.engineeringforchange.org/news/the-concrete-lathe-world-war-i-technology-meets-21st-century-design/amp/


Brian
A guy that crushes rock for a living

On Sun, May 21, 2023 at 5:41 AM gene heskett  wrote:

> On 5/21/23 05:00, Nicklas SB Karlsson wrote:
> > l�r 2023-05-20 klockan 23:28 +0700 skrev Thomas J Powderly:
> >>
> >> I saw an overarm router recently
> >>
> >> and wondered if a sewing machine frame was stiff.
> >>
> >> Compared to a desktop gantry mill.
> > Gantry ought to be more stiff.
> >
> >
> That depends on the gantry, my 6040's x rods could be stiffer than they
> are, so light cuts are the order for smooth finishes. as is a mist
> coolant directed at the tool.
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>   soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>   - Louis D. Brandeis
> Genes Web page 
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Sewing Machine Stiffness

[BRIAN GLACKIN]

Epoxy is a bonding agent
Fiber (glass or otherwise) add cross linking in the resulting matrix.

Thes two Used alone, the resulting composite will be weak.

You need sized aggregate to make a much more rigid and robust structure.
The epoxy is then strongest bonding all these parts together

Sand and fines to fill the spaces between larger aggregate.   The top size
of the aggregate will depend on the thinnest portion of the structure but
generally 13-19 mm max.

During ww2 they made lathes bodies out of concrete with imbedded steel
parts that were jigged in form or line bored for the spindle and tail
stock.

https://www.engineeringforchange.org/news/the-concrete-lathe-world-war-i-technology-meets-21st-century-design/amp/


Brian
A guy that crushes rock for a living

On Sun, May 21, 2023 at 5:41 AM gene heskett  wrote:

> On 5/21/23 05:00, Nicklas SB Karlsson wrote:
> > lör 2023-05-20 klockan 23:28 +0700 skrev Thomas J Powderly:
> >>
> >> I saw an overarm router recently
> >>
> >> and wondered if a sewing machine frame was stiff.
> >>
> >> Compared to a desktop gantry mill.
> > Gantry ought to be more stiff.
> >
> >
> That depends on the gantry, my 6040's x rods could be stiffer than they
> are, so light cuts are the order for smooth finishes. as is a mist
> coolant directed at the tool.
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Cheers, Gene Heskett.
> --
> "There are four boxes to be used in defense of liberty:
>   soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
>   - Louis D. Brandeis
> Genes Web page 
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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[Emc-users] free drive mode

[theman whosoldtheworld]

a curiosity: when the cobots press the freedrive button, they use
torque sensors such as ? on an admittance based control or just add
and subtract torque to the loop in torque control?


I would implement these function on my robot.

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Re: [Emc-users] Sewing Machine Stiffness

[gene heskett]

On 5/21/23 05:00, Nicklas SB Karlsson wrote:

lör 2023-05-20 klockan 23:28 +0700 skrev Thomas J Powderly:


I saw an overarm router recently

and wondered if a sewing machine frame was stiff.

Compared to a desktop gantry mill.

Gantry ought to be more stiff.


That depends on the gantry, my 6040's x rods could be stiffer than they 
are, so light cuts are the order for smooth finishes. as is a mist 
coolant directed at the tool.



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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 



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Re: [Emc-users] Sewing Machine Stiffness

[gene heskett]

On 5/21/23 02:56, marcus.bow...@visible.eclipse.co.uk wrote:

On 2023-05-21 03:43, Chris Albertson wrote:


Even 3D-printed PLA plastic can be strong enough.  I have a 3D-printed
CNC conversion of a harbor freight milling machine.  Normally they use
metal parts for the motor mounts and such but PLA can be just as rigid
if you make the parts thicker.



Yes; I have printed parts for several small machines for manually 
cutting tube, and I have printed and used some large fixtures which hold 
parts for milling, all quite successful. The key lies in the design, 
taking account of the properties of the printed material. So I guess its 
the same with epoxy/fibre. I have used glassfibre and epoxy for repairs, 
but hadn't thought to use it for structural purposes on a new part, so I 
must try that. Thanks for the suggestion.


Marcus

I'm using PETG+CF for parts where it s/b more rigid. Not as strong as 
pure petg, but much more rigid. Its abrasive though, so don't use for 
rubbing parts, bolted seems ok. I have two motor mounts in plain petg, 
seems to be rigid enough.


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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 



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Re: [Emc-users] Sewing Machine Stiffness

[Nicklas SB Karlsson]

lör 2023-05-20 klockan 23:28 +0700 skrev Thomas J Powderly:
> 
> I saw an overarm router recently
> 
> and wondered if a sewing machine frame was stiff.
> 
> Compared to a desktop gantry mill.
Gantry ought to be more stiff.




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Re: [Emc-users] Sewing Machine Stiffness

[marcus . bowman]

On 2023-05-21 03:43, Chris Albertson wrote:


Even 3D-printed PLA plastic can be strong enough.  I have a 3D-printed
CNC conversion of a harbor freight milling machine.  Normally they use
metal parts for the motor mounts and such but PLA can be just as rigid
if you make the parts thicker.



Yes; I have printed parts for several small machines for manually 
cutting tube, and I have printed and used some large fixtures which hold 
parts for milling, all quite successful. The key lies in the design, 
taking account of the properties of the printed material. So I guess its 
the same with epoxy/fibre. I have used glassfibre and epoxy for repairs, 
but hadn't thought to use it for structural purposes on a new part, so I 
must try that. Thanks for the suggestion.


Marcus


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