Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- CAD-CAM-EDM-DRO
- Messages
Search
|
Re: How do I 'make' a ballscrew antibacklash nut?
dspinnett
Thanks Ray.
toggle quoted message
Show quoted text
My work envelope at one shot is rarely over 6" anyway. Would that justify .001 screws and anti-backlash? I'd like to be accurate over 6" within a couple thou if practical. Final goal is to make mini running engines, and probably a full size engine too. The 'Griz' doesn't seem too bad overall - better quality that the lathe anyway. (both are brand new). --- In CAD_CAM_EDM_DRO@y..., "Raymond Heckert" <jnr@a...> wrote:
Ball screws are practically anti-backlash, nevertheless, |
|
Re: How do I 'make' a ballscrew antibacklash nut?
dspinnett
Some ballnuts has one end with outside fine treads on it, put bothfrom each other thus, preloading them.for small loads. Ah, I think get it. If I went the adjusting nut route, I would thread both ball nuts into the center coupling nut then mount just one of the ball nuts to the bed attaching where the original split brass nut went? If so, should be easy enough.. On the square ball nuts, is there room to bolt the flat directly through the corners of the body, or do you always have to have a flange to mount to? Thanks for the input.. Dave. |
|
Re: DRO issue "HEDs in hand"
j_e_f_f_williams
OUCH, $85.00 each for the scales?? Guess I might not get more from
them..... Here is the text from them when I ordered back in January: They are 12.5 Cycles Per mm scales that you could piece end to end. They produce 25CPMM when used with the Module. The price for the scale is $49.00 each. The Module model # would be LM-25CPMM-3T. We do not have Distributors in Canada as yet. You may order directly from the factory here in Fallbrook CA. We accept Visa and MC. The 12.5 [scales] are CPMM (Cycles Per Millimeter). When used with the LM-25CPMM-3T Modules, which doubles the scale resolution, they will produce 25 cycles per mm in quadrature or 0.01 mm resolution after x4 edge detection I wonder why the huge increase in the scale price. Jeff --- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote: Fast response time on Encodertech's part (like within 3 minutes of myuntil someone pays for the master to be made ($1200) and then only thelength that customer pays for will be made. The price of the LM25cpmm-3S Module is |
|
Re: DRO issue "HEDs in hand"
j_e_f_f_williams
Hello,
I was told the same thing. It's actually the 12.5CPMM scales I have but the 25CPMM modules somehow double the resolution?! I eventually had to specifically ask for the scales that matches the 25CPMM modules. Jeff --- In CAD_CAM_EDM_DRO@y..., "John A. McFadden" <mcfadden@c...> wrote: As of 10/11, Encodertech did not have any 720CPI strips in stock inlengths above 3.25", that might have changed, I did not ask. I'll look into it. |
|
Re: Tonmac Mills - Good Choice for Retrofit?
Jerry Kimberlin
natchamp_87 wrote:
I know its not a BP, but what do you guys think?It is an attractive price and machine size. In fact I might be interested. They are made in China, however. That may be a downside against which one could compare those made in Taiwan. See offerings at: . If you go thru all the pages, you will come to the GEM500GV and the GEM600PV. A couple years ago these machines were offered in CNC versions with ball screws, etc. We were all wondering if the GEM500 could be had without the control, but with the ball screws. Inquiries never came to anything so far as I know. The GEMs are mill drills but very unordinary ones. I've never seen a tonmac so far as I know. They may be rebranded over here, of course. Have you actually seen one in the flesh? OTOH, a decent Bridgeport (Boss 6 or better with servo motors) can be had for less money, or so I'm told. JerryK |
|
Tonmac Mills - Good Choice for Retrofit?
natchamp_87
I'm still in the process of deciding what mill to get for my retrofit
project, burning lots of midnight oil on the net. I came across this manufacture: I can purchase this brand spankin new for 2k. Only problem is shipping which is 1,700 to West coast. I might be able to piggy back on another shipment because the 20' cargo container can hold way more than one machine. I know its not a BP, but what do you guys think? Mark |
|
Re: DRO encoders- Rotary or Linear?
gittt2000 wrote:
Linear - without a shadow of doubt. Here's why :Well, yes, in $100,000 CNC machining centers, no argument! Notice, though, that the graphs are in uM units, the ballbar plots are 5 uM/division! To be of much use, the linear scales must have resolution on that scale, or these errors would lie undetected underneath the basic resolution of the scale. What is the standard resolution of typical DRO scales? .0005" ~= 12.7 uM if I computed it right. So, the backlash errors they showed would be barely one quantum on the typical DRO scale. Linear errors due to screw expansion depend on how hard you run the machine. Note the thermograph of the hot screw was run continuously for 6 hours at 24 M/Min. That equals 945 IPM. Are you planning to keep your machine running at almost 1000 IPM for 6 hours? If I tried to move my Bridgeport at 1000 IPM, if would hurl itself over so hard it would break the floor slab! So, while the things stated in the Heidenhain article are real concerns for makers of dedicated, HIGH-precision CNC machining centers, and more important as size and speed increase, they may not be so significant for small machines. If you price linear scales with sub-micron resolution, you'll find them pretty expensive. Jon |
|
Re: DRO encoders- Rotary or Linear?
While the linear encoders may be better for the purposes of this list I
toggle quoted message
Show quoted text
think the question is really: 1 - Is my machine such that I would notice any difference? 2 - Even if I could notice a difference is the cost/benefit at a point that makes sense for me. I run my Bridgett my Bridgeport series II on Gecko G320 drives with rotary encoders on the motors. The accuracy and precision with the rotary encoders is more than adequate for my purposes. It will easily hold to less than .001" and I can sell all the stuff I produce on the machine. Spending the money to upgrade to linear strips would buy me nothing as the items I am producing would not become any more valuable and no one would pay more money for then. It is all a balancing act to get the accuracy and precision needed and not waste money getting more. Also remember what the rest of your machine is capable of. Putting on super high resolution linear encoders on a mill drill conversion is probably a waste as the rest of the machine will have enough play and flex that you will not likely see an improvement. Also remember that setup of the part can have a huge impact on machining precision. A weak setup will introduce more inaccuracy than the difference between linear and rotary encoders. Ditto with thermal expansion. So, if you are not using flood with the coolant being held to a relatively constant temperature than you will also have inaccuracy. In summary, my point is that you have to consider the whole and not just focus on one part. Like so many things in this hobby it is easy to get into a pissing match where the claims of what is required no longer fit the reality of most machining much less hobby machining. So if you really feel your setups will be rigid enough to allow machining to .0001" and you will control the temperature, and your machine is capable of moving that small an increment, than maybe the linear encoders will make sense. Tim [Denver, CO] ----- Original Message -----
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ |
|
Re: Bridgeport Series II CNC specifications
tmartin23 wrote:
I have the opportunity to try to squeeze one of these machines intoSeries II specs : Height 92.75" with 4J head and rigid ram Depth 76.25" Width 79.75" Weight 4750 Lbs These are for the manual machine, so the depth and width may be different for CNC. Jon |
|
Re: Bridgeport Series II CNC specifications
Mine is not a rigid ram, but the style that allows the head to tilt side to
toggle quoted message
Show quoted text
side. It is about 94" to the top of the motor. 84" sounds more like a series I. There are pictures of the machine at www.KTMarketing.com/CNC.html in the pictures section. Tim [Denver, CO] Sherline products at Deep Discount www.KTMarketing.com/Sherline ----- Original Message -----
I have the opportunity to try to squeeze one of these machines into |
|
Re: plasma cutter/machine torch
Any plasma cutter and torch you select follow the
recommendations Peter from prenolds@... , sent to me. "If you believe that you may automate your plasma cutting at some point, you must select a unit that does not use a high-frequency starting circuit. This causes electrical interference such as locking up the computer, destroying files, etc. None of Hypertherm's Powermax units use a high frequency starting circuit." One website that has a good FAQ is: If I had known this ruler before, I had avoid more than 6 frustrating months and a lot of money. Raul __________________________________________________ Do you Yahoo!? HotJobs - Search new jobs daily now |
|
Re: DRO issue "HEDs in hand"
is the url for the
toggle quoted message
Show quoted text
linear encoders. I don't think it showed how I mounted the mylar strip in the 1X2 rectangular tubing. Bascially, I used double sided 3 mil tape cut down to 1/4" wide which was used to stick the mylar strip to a piece of 1/4" aluminum square stock that was installed into the housing. The slider machine to allow for the square stock. Dan -----Original Message-----
From: Roger Linscheid [mailto:r.linscheid@...] Sent: Tuesday, October 29, 2002 7:48 PM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Re: DRO issue "HEDs in hand" Thanks for the info, I think I'm going to give it a try. I feel that the resolution should be adaquate for the majority of the work that I do. Dan, how did you mount the strip? I was thinking about a fiberglass plane to support the strip. Hopefully this would lessen the effects of temperature on the system, but perhaps this isn't needed. I remember a website with pics of a linear encoder installation but I guess I didn't bookmark it. Does anyone have a URL showing this setup? |
|
Re: Drill press & cross-slide vice
Been there and done that. I used the 5" version from harbor freight for
toggle quoted message
Show quoted text
around 60.00 I had to take a lot of slop out of the drive mechanism and made some stepper motor mounts. I install Torrington needle thurst bearings on each axis. I used it to cnc drill some stepper motor mounts. The problem is that you cannot use a drill press as a mill because of the slop in the spindle assembly. The enco mill drill tables for $119 is a better deal in the long run but figure out how you plan to do the spindle first. Dan -----Original Message-----
From: vandersandtc [mailto:vandersandtc@...] Sent: Wednesday, October 30, 2002 12:52 AM To: CAD_CAM_EDM_DRO@... Subject: [CAD_CAM_EDM_DRO] Drill press & cross-slide vice Now my question : I bought a cross-slide vice yesterday and my first thought was 'Hey, if I stick some steppers on this sucker, mount it on my drill press then I might have a cheap mill' - I suppose a lot of people have asked this question before. I would like to hear your comments please. Regards Coert Addresses: FAQ: FILES: Post Messages: CAD_CAM_EDM_DRO@... Subscribe: CAD_CAM_EDM_DRO-subscribe@... Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@... List owner: CAD_CAM_EDM_DRO-owner@..., wanliker@... Moderator: jmelson@... timg@... [Moderator] URL to this group: OFF Topic POSTS: General Machining If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill List Mom List Owner Your use of Yahoo! Groups is subject to |
|
Re: DRO encoders- Rotary or Linear?
John A. McFadden
Matt:
Thats probably the system my dad saw at Lockheed (one of his friends works for Lockheed in a machine shop and my dad asked him for advice on my DRO idea), it was a brand new CNC mill, just delivered the week before. I guess the problem would be putting the load on the roller, it doesnt seem like it would be easy to do. John |
|
Re: DRO issue "HEDs in hand"
John A. McFadden
Roger:
toggle quoted message
Show quoted text
The strip has to be seperated from any support by a fraction of an inch (1/4" I think), as the encoder surrounds the strip on three sides (as it uses light passed through the strip to read the lines). John [snip] Dan, how did you mount the strip? I was thinking about a fiberglass |
|
Re: DRO encoders- Rotary or Linear?
alex
Thank you.
toggle quoted message
Show quoted text
Alex ----- Original Message -----
From: Jon Elson <elson@...> To: <CAD_CAM_EDM_DRO@...> Sent: Wednesday, October 30, 2002 2:09 AM Subject: Re: [CAD_CAM_EDM_DRO] Re: DRO encoders- Rotary or Linear? aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill |
|
Re: DRO encoders- Rotary or Linear?
alex
OK, thank you.
toggle quoted message
Show quoted text
----- Original Message -----
From: Raymond Heckert <jnr@...> To: <CAD_CAM_EDM_DRO@...> Sent: Tuesday, October 29, 2002 11:18 PM Subject: Re: [CAD_CAM_EDM_DRO] Re: DRO encoders- Rotary or Linear? Alex, It's not merely a backlash issue. (Although, aaol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble. sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill |
|
Re: DRO issue "HEDs in hand"
j_e_f_f_williams
Hello,
toggle quoted message
Show quoted text
I am using linear strips/encoders from www.encodertech.com. The encoder and strips are about the same price as the US Digital stuff and comes in a 0.01mm resolution which is about 0.0004". The module is a LM-25CPMM-3T and you can get 600mm length strips. The scales are $49.00 and modules $39.00 (almost a year ago). You can order right from them and they are in Fallbrook CA. I have no connection to them other than I used their product on my lathe. I am in Canada and am used to working in mm so the .01mm accuracy worked out well for me. TTYL, Jeff --- In CAD_CAM_EDM_DRO@y..., Ken Jenkins <kjenkins@b...> wrote:
I posted a message a few days ago regarding the U.S. Digial Linear |
to navigate to use esc to dismiss