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Discussion in 'BRIDGEPORT MACHINES INC. & B'PORT CLONES' started by Rick_B, Feb 21, 2017.
The "free shipping" from China always amazes me.
I've looked at both Ebay and Aliexpress and I must admit its mind boggling. Prices seem to be all over the place - but the three I have focused on are Bob's recommendations above for $235 and $435 and Holescreek suggestion linked here http://www.ebay.com/itm/182295304583?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
I don't see a lot of difference so I'm wondering if anyone has experience with the specific Aliexpress models and how they might compare to Holescreek suggestion.
I think the quality of the manual on the Eason unit has to be better since so many home guys swear by them and the US companies sell them for greatly marked up prices. I believe I mentioned that the chinglish of the manuals I got was the worst I'd seen.
I looked at the links above too and the scales appear to be coming from the same factory, or at least the parts are coming from the same suppliers. The only difference being the color of the wiper seal (yellow vs. black) The readouts themselves are all different, the $235 unit has a layout similar to my Meister Top10 unit.
I have no idea how those units actually compare as delivered. And, with how quickly that market has been changing, I don't think anyone really knows the current marketplace and how the different units truly compare, especially thinking down the road 5 or 10 years. And if the sellers do know, they are only telling their own version of the story. You pay your money and take your chances. When I am guessing, I guess with the low cost version. Just me... Others want someone to hold their hand, and that is understandable. It is an expensive hand hold, though... My current mode is to just wait. Prices have been tanking on DROs, and it doesn't look like that will end anytime soon. I get by pretty well with just using the dials.
As I continue to flip the should I/Shouldn't coin I got to thinking about some of the old school versus DRO advantages and some comments (maybe here maybe somewhere else) relating to horse and buggy versus car. I was thinking about this as I was doing some yard work - hauling stones, debris around - I thought I really don't need a lawn tractor and cart - I could do the work with a wheelbarrow. It would be slower and more tiring but the job would get done. It sure is esier and ,more enjoyble to use the tractor and cart. I decided to stop flipping the coin and just get the DRO.
It's going to be a 3 axis unit and an import. I haven't decided which one yet but am leaning towards the lower cost unit - given no obvious difference. One open question is how you size the scales. Is it table length, width or table travel. I saw somewhere that it was table travel plus 140 mm (I think).
Any advice on scale sizing?
It depends on the seller's interpretation from the manufacturer. It took me a while to get it through my sellers head that I didn't care about OAL, just travel length. He kept wanting to add the 140mm on top of what I asked for. He finally gave up and gave me what I asked for.
Here's another fairly recently added option:
http://littlemachineshop.com/products/product_view.php?ProductID=5515&category= (scale specs can be seen here)
This system was designed to work with Yuriy's Toys Touch DRO system.
I believe Yuriy's controller will work better with these scales and as such, have ordered his quadrature controller (http://www.yuriystoys.com/p/store.html).
I didn't order the complete kit, just the scales and readheads (sold separately):
Here http://littlemachineshop.com/products/product_view.php?ProductID=5499&category= and here http://littlemachineshop.com/products/product_view.php?ProductID=5498&category=
The cost saving on the components more than pay for the pre-built controller from Yuriy's site or you can make your own for additional savings.
Touch DRO is an App based DRO display, for those who don't know, that requires an Android tablet.
As an 'Open Source' system, it is continually being updated, refined, and added to by an entire community of people that are available online for help/assistance if needed.
The advantages to this type DRO as I see them are:
1. Flexibility, can have 2 or 3 axes. A forth axis (labeled "W") on the system can be used (usually, for a tachometer, but has other uses).
2.Memory, only limited by the amount on your tablet, expandable via micro SD cards. This also allows for having back-up copies.
3.Instant updates via the internet.
4.Versatility. Since the controllers connect to your tablet via Blue Tooth, you can connect multiple machines.
I plan on doing a pictorial post of the install an operation once the components get here and I have time to install them.
That is great JPigg55, but it still costs double what an Aliexpress kit with glass scales costs, and only advertises .002" accuracy, though it may actually be better. It also still takes some user effort to get it all working with the Android tablet. I am a big supporter of Yuriy and his work, and of the universality of his designs. The issues are still pricing totals, expected accuracy, and plug and play in my mind...
I totally agree with you Bob.
For me, however, this was a better option as scale size and length are issues for me. Magnetic scales are much smaller and way easier to cut to length.
Had I been able to find glass scales that were the correct length for my machines, I may have gone that way as it is much cheaper with an increase in accuracy.
I just wanted to post another option for those like me where glass scales may not be an option.
I also like the fact that I can easily replace any component that may go bad instead of having to buy a whole new system a year from now because one thing broke and replacement parts are no longer available.
I've been pondering this while takingadvantage of good weather to get some yard projects done. I've decided I am getting a DRO and likely one of the lower cost models we have been discussing. I'm still struggling with scale sizing. According to the Bridgeport manual my mchine, with a power feed, has 16-1/2" of X axis travel, 12" of Y axis and 16" ofZ axis. I need to verify those numbers but assuming they are correct what would the scale lengths be. It seems most suppliers use a formula relating to travel + 140 mm. So do I just measure the travel, add 140 mm and order that scale overall length?
To find the "real" travel, don't read the manual, move what you are trying to measure all the way to one end of it's travel until it stops, put a Sharpie mark across the interface between moving and stationary parts, move it all the way in the other direction until it stops, and then measure between the half Sharpie marks.
Thanks Bob - that's what I had in mond for verifying travel spec's from the manual.
Forgot to mention that you also need to move any stops, dogs, or other adjustable features that can limit the travel of the axis, out of the way or at least loosen them so they can slide. Make sure you are achieving the full travel possible for each axis.
Robert I will be following your post here,if you will please let us(me) know what you order from who.There are so many choices out there it can/does give a person headache.Your questions and answers you receive has cleared up alot of ?marks in my head.So now I guess it comes down to who to purchase and what model from.Sounds like your budget and mine are about the same and I'm others as well.So we are not along on these issues,if I may also suggest to do a search on Youtube.There are several that I think is helpful on installing and what works for us guys that don't do this every day.Myself I am going close to pulling the trap off my BP and getting started on setting it up and install a DRO.Thanks for posting and asking some really good questions---kroll
I guess if a person keeps looking and researching you will find something else to ponder over http://www.star-techno.com/
I measured the actual travel on my Bridgeport - X = 17-3/4" (32" table with a power feed), Y = 10-1/2" (movement got very tight at back - I think the gib adjustment is too tight at the back side. I have another 2" or so of space so I'm going to assume Y = Bridgeport spec of 12"), Z = 16".
When I convert that to MM I get X = 451, Y = 305 and Z = 406. I saw on holescreek thread where he used 800, 350 and 450 for his 42" table machine and he mentioned that the X axis was about 12" longer than needed but it wasn't a problem. Right now I'm thinking I would order 600, 350 and 450 (X, Y and Z respectively). The question I have is that when I look at the offerings I typically see
Scale Length available
physical length is differnt from the travel length
physical length = 140mm + travel length
So if I want a 600 mm overall length what do I order - 600 - 140? Or is the statement above saying 600 mm scale will give you 460 mm of travel? I think I've got tunnel vision about this
Is there a good reason for ordering so much oversize? The main consideration beyond having enough travel is how and where you are going to mount them. Mock them up if necessary. You post does not show if the seller wants travel length or physical length to be supplied, or both. Make sure what they are asking for, and then make it very clear to them what dimension(s) you are supplying, keeping the language barrier in mind... Best is to use the exact nomenclature and sizing system (mm or inch) that they are asking for. Don't complicate things or it can and will get confused.
Bob - I am assuming when you question why oversize that you are referring to the X axis - the Y and Z are only 2 inches or so longer than travel.
Regarding the X - I was going off of holescreek's comment that a bit longer was not a problem and that it made locating the scale a little easier. Given that the cost is the same for the scales withing the range offered above - I'm wondering why a bit longer would be an issue for the X axis?
My comment was more along the lines of "figure out where and how you want to mount the stuff and then order stuff to fit that plan."
Thought I'd post the unboxing photos of The Little Machine Shop DRO I spoke of before in this thread.
Added a couple shots of Yuriy's quadrature adapter too:
Bob - given that I have never seen a DRO in person (just internet pictures) and that I have no experience with mounting a DRO - its going to be difficult for me to figure out where and how it would be mounted. I was assuming that with a "standard Bridgeport" there would not be all that many options for mounting. X on the back of the table, Y on the saddle and Z on the frame next to the knee. I'm sure within those general parameters there are variations but I'm betting there are not a lot.
Without only limited knowledge of how a DRO actually works, I am assuming the scale attaches to a fixed surface and the reader head attaches to the moveable surface you are attempting to measure. Again - with a standard Bridgeport, the Y and Z are a given (I think) but the X has some variability related to table length. However, my thought right now is that as long as the overall length of the scale doesn't exceed the table length and is longer than the table travel then any length will work. I was hoping that someone who has installed a DRO on a Bridgeport could simply validate the X, Y and Z numbers I proposed above.
I measured the scale length on my 32" table BPM and it measured 660mm That length did not include the end caps, just the scale itself. You'll be fine with a 600.
Just be sure that your seller understands that you are asking for "travel length" when you order.
There is quite a bit of information and various installs on the DRO Pros website: http://www.dropros.com/Digital_Readout_DRO_Installation.htm
My calculations based on the travel measurements using glass scales would be:
X scale overall length of 600 or 650mm
Y scale overall length of 450 or 500mm
Z scale overall length of 550mm
You need to take a look at the mounting surfaces to make sure nothing is obstructed, I would get the slightly longer scales on the X and Y if you have the space. I would order the scales as they indicate which is overall length based on their calculations. I find that if you ask for anything else, you might not get what you want, especially when your are ordering from Asian sellers.
The X scale is mounted to the table which is the moving surface. the reader is mounted to the saddle.
The Y scale is mounted to the knee and the reader is mounted to the saddle.
The Z scale is mounted to the column and the reader is mounted to the knee.
Since the surfaces may not be even (with the exception of the X axis on the table), you need the ability to adjust both the reader and the scales so that everything is run parallel and true. This is usually done with a test or dial indicator. I mount my Y and Z scales on aluminum rectangular bar stock usually with 4 jacking screws. Scales also come with jacking screws on either end and the mounting holes are usually slotted to allow some adjustment.
I posted this thread quite some time ago. Then I was very disappointed but now having become used to it, and having used some of the most useful functions, I see nothing wrong with the unit, only bad instructions and paper work. (actually if you know Chinglish, they're not that bad. It just took lots of video watching to figure it out)
I've used the bolt circle function many times and centering is a breeze. The line hole and arc functions are also good to have.
If I had it to do again, I still couldn't resist the low price.
I may not have the best tools but I have lots of them. Besides, I'm not making my living with this stuff. That would entirely change the picture. The tools I MADE MY LIVING WITH (now retired) were only brand name top shelf.
Thanks Aaron - I've firmly decided to go with oe of the lower cost models - now I just need to get by a dozen other things in front me (unrelated to the shop unfortunately) and get to ordering one of them.
Good morning,Rick any updates or pics of what you pickup?Boy I would like to purchase from DRO pros but my pockets just won't allow it.Lots of info on their site and a warranty with support,but I also will have to go with the cheaper so rolling the dice.
Unfortunately I haven't made any progress with this project - I've been taking advantage of the nice weather. 10 yards of mulch and 8 yards of run a crush. Hopefully I will be getting to this soon. My current plan is to get the same unit asd Holescreek referenced up thread - unless I win the loottery