X axis spring back on vice squaring ?

[ninefinger]

The suggestion of the oil system was a "long shot" if nothing else panned out. As it turns out you've found a very likely source of the issue in your Y axis gib strip. Definitely try lapping the Y gib on flat surface as mactec suggested. That 1.5 thou gap will be the source of much of that spring back you are seeing. Lap both sides to ensure they are flat while trying not to introduce any change in the taper. Put it back in, adjust as necessary and try again, should be much better. These machines are far from perfect and trying for perfection is usually an exercise in futility. However you can get better than factory results by doing exactly what you are doing - studying the issue and making logical decisions based on the results of the investigation you've performed.

Good luck and let us know what you do and how much it improves the situation.
Mike

[handlewanker]

Lapping??.......oh yes, I had to read post #17 again as I misread it as tapping......oops.

The problem still lies in the fit of the Y axis gib to both sides of the gap between the base casting dovetail and the saddle........this is a precise fit as the gib must touch both side faces EXACTLY.

As I said, this can only be done by careful observation of the blued areas and scraping.

At the same time you also FIRST need to determine whether or not the sides of the saddle dovetail and the base dovetail are true.

You need specifically shaped straight edges to determine that.........just bluing the gib and seeing bald spots only tells you one or more of 2 faces in the dovetail cavity and the 2 faces on the gib are not 100% flat.

What is the use of having a perfect gib if the dovetails are not also perfect.

YOU CANNOT FIT A TAPERED GIB TO A DOVETAIL UNLESS THE DOVETAILS ARE FIRST MADE TRUE.

The assumption here is that the dovetails themselves are perfect.......would you lay money on that?......and you also forget that there are other surfaces on the top and bottom of the slideways that must be perfectly fitted too.

So, now we have a more complicated scenario to pursue........otherwise you will end up with a machine that has dovetails that are all over the place.

My opinion is.....as this is a new machine that has been retrofitted, it would be fair to say that the quality of the machined surfaces are as good as it's going to get for the price paid...... so live with the "quality" you have purchased and go on to make chips.

Any subsequent messing with the slideways fit will not make things better........that is, unless the person doing the job is a machine tool fitter with the equipment and skill to work on cast iron slide ways dabbling with the machine will only make things worse......and there is no going back from that outcome.
Ian.

[ti5m]

Great info thanks guys.

Its just a hobby for me and i have no skills to properly fix dovetails so i think i will just leave it and make chips as you say. I dont have any tools or skills to check the dovetails to see if they are ok, so in fear of making things worse i shall leave them alone. Just tightening up the Y gib alone has made quite a difference so its probably fine for what i need it to do. Backlash in mach3 is set to 0.035mm for X and Y and 0.04mm for Z. I dont know if thats acceptable or not? But its as good as i have been able to get it so far.

[mactec54]

Lapping??.......oh yes, I had to read post #17 again as I misread it as tapping......oops.

The problem still lies in the fit of the Y axis gib to both sides of the gap between the base casting dovetail and the saddle........this is a precise fit as the gib must touch both side faces EXACTLY.

As I said, this can only be done by careful observation of the blued areas and scraping.

At the same time you also FIRST need to determine whether or not the sides of the saddle dovetail and the base dovetail are true.

You need specifically shaped straight edges to determine that.........just bluing the gib and seeing bald spots only tells you one or more of 2 faces in the dovetail cavity and the 2 faces on the gib are not 100% flat.

What is the use of having a perfect gib if the dovetails are not also perfect.

YOU CANNOT FIT A TAPERED GIB TO A DOVETAIL UNLESS THE DOVETAILS ARE FIRST MADE TRUE.

The assumption here is that the dovetails themselves are perfect.......would you lay money on that?......and you also forget that there are other surfaces on the top and bottom of the slideways that must be perfectly fitted too.

So, now we have a more complicated scenario to pursue........otherwise you will end up with a machine that has dovetails that are all over the place.

My opinion is.....as this is a new machine that has been retrofitted, it would be fair to say that the quality of the machined surfaces are as good as it's going to get for the price paid...... so live with the "quality" you have purchased and go on to make chips.

Any subsequent messing with the slideways fit will not make things better........that is, unless the person doing the job is a machine tool fitter with the equipment and skill to work on cast iron slide ways dabbling with the machine will only make things worse......and there is no going back from that outcome.
Ian.

So you are a journeyman 5 year apprenticeship 10,000 hrs., I know the system well and used to teach guys like you, some have what it takes some do not, I wonder where you fit, you can usually tell by there HS education they have, as to how well they will do

Another Rant with NO HELP to anyone, especially, to the OP, The Zone is about helping someone correct a problem the simplest way, not what a machine rebuild shop would do

You could not even do this yourself so why suggest the impossible, Show us some of your recent scraping work, how many spots per inch can you achieve, Show us a photo of you scraping gear you have, you can't do this with just some blue and a hand scraper, if you say you can it's just more of your BS

So as I said in my other post that you could not read, you gave your best uneducated guess and trashed the post

So I say it again as ninefinger has also, the OP could Lap the Gib flat without any special tools or knowledge of scraping, this won't solve the problem completely but would be a start in the right direction, the next problem to solve is to stop the Gib from moving as right now, when the axes changes direction, the Gib is moving a small amount, that is why you are seeing the change on your indicator

[handlewanker]

But Mac......as you don't know anything, I'll explain a few facts.....lapping the gib will produce something that isn't fit for it's use and won't be suitable for the job......WHY......BECAUSE YOU NEED TO ASCERTAIN THAT THE DOVETAILS IN THE MACHINE ARE IN GOOD ORDER FIRST AND NOT JUST GROUND TO A FINISH TO FOOL EVERYONE......only then can you fit the gib.

BTW......as it's off topic for this thread I'll reply briefly to your doubt........I acquired a 1920 vintage Colchester Bantam lathe back in 1980 in UK and brought it to OZ when I emigrated

As the bed at the chuck end had .013" wear and made adjusting the saddle impossible......yes, that is thirteen thou wear on the 2 raised vees etc, .......the lathe was stripped down for a refit.

This tear down and rebuild has been posted here on another thread in the late 90's, but a long story short, I recut the 2 raised vees and the flats....top and bottom..... with a hand planer and then re-scaped the saddle to fit......I've been doing that type of work on and off almost all of my working life.

All of this is really coincidental as I would expect a new relatively inexpensive machine like the BF20 in this post to be of a reasonable quality........some minor build discrepancies can cause a bit of bother if you're really really fussy, but after the machine is used for a while it will take up a different characteristic......they all do.
Ian.

[mactec54]

But Mac......as you don't know anything, I'll explain a few facts.....lapping the gib will produce something that isn't fit for it's use and won't be suitable for the job......WHY......BECAUSE YOU NEED TO ASCERTAIN THAT THE DOVETAILS IN THE MACHINE ARE IN GOOD ORDER FIRST AND NOT JUST GROUND TO A FINISH TO FOOL EVERYONE......only then can you fit the gib. .

Really, you are clearly that does not know what can be done!!!

BTW......as it's off topic for this thread I'll reply briefly to your doubt........I acquired a 1920 vintage Colchester Bantam lathe back in 1980 in UK and brought it to OZ when I emigrated

As the bed at the chuck end had .013" wear and made adjusting the saddle impossible......yes, that is thirteen thou wear on the 2 raised vees etc, .......the lathe was stripped down for a refit This tear down and rebuild has been posted here on another thread in the late 90's,
Ian.

Why would you buy a 1920's machine like this in the 80's, when Colchester had much better and useful, machines, that where worth rebuilding if they needed it, the best pick started in the 60's when they made some of the best lathes in world

You would of had a hard time Posting that project here in the 90's as you never joined until 2006, and the post would still be here

[handlewanker]

Oh Mac....thanks for the photo.....that is the exact same model I bought back in 1980 just before I emigrated to OZ assuming it was a far off the planet colony and machinery would be hard to come by....apart from the cost factor etc etc.......long boring tale.......there's many a good tune played on an old fiddle etc.

Got my dates mixed up........I rebuilt it in the mid 80's and probably posted on a thread discussion about it sometime in the mid 2000's......I think the thread was about a 9" South Bend rebuild and the cost to outsource the bed grinding etc, hence the mention about my lathe bed being recut with a hand planer.

That lathe was dug out of a bombed shadow factory site and was acquired by a scrap dealer but I got it before it was broken up for scrap...........cost me 100 pounds back then, a weeks wages.........came with a complete set of change wheels too.

Colchester have come a long way since then.....I worked on a couple of their later models in the mid '70's so know what they are like.

The bed has 2 raised vees and 2 flats like the South bend 9" models.

Anyway, on the BF20 mill, lapping the gib would be a dodgy exercise as you would have to fit and refit it to get an indication of the contact areas and if you inadvertently rocked it during the lapping process you are in deep sh!t.......that is a fact.

As I said, this is a new machine.....I wouldn't advise anyone to mess with it if they weren't really up to the task.

Supposing there was a thou or two discrepancy in the actual dovetails.....out of parallel etc......no amount of lapping the gib is gonna cure that.......you have to FIRST ascertain if the dovetails are good.........that mill retails for approx. A$1,700 on EBAY, so is not really an expensive piece of kit, but it's quite adequate for the work it was designed to do.......going to a CNC mode opens up a can of worms you don't need to anticipate.

CNC is all about relying on the final outcome by the exactness of the machine's build........after you push the green button.

Manual machining is walking up to the final outcome by hands on skill and application of your experience.

When you don't have the experience or skill to work metals with relatively complicated machinery, then you rely on the inbuilt capabilities of the CNC machine to do it for you.......that is a fact.
Ian.

[ti5m]

Actually Ian its not a BF20 that i have. I have the bigger MH28V. A$2,400 machine.

[handlewanker]

Yessss......I seem to have been thinking of the BF 20 from another thread.and was browsing it's specs so it stuck in my mind......don't tell Mac or he'll have an apoplectic fit, he didn't notice the error either.

It will be interesting to see how the parts turn out after a bit of slide adjusting.......probably any error will be of miniscule proportions.
Ian.

[mactec54]

Yessss......I seem to have been thinking of the BF 20 from another thread.and was browsing it's specs so it stuck in my mind......don't tell Mac or he'll have an apoplectic fit, he didn't notice the error either.

It will be interesting to see how the parts turn out after a bit of slide adjusting.......probably any error will be of miniscule proportions.
Ian.

Why would I have an apoplectic fit, we are quite used to your inaccurate rants, we know how you post, it's all about you, which nobody is interested in, the deal is that you don't seem to understand, Posting is to help the OP not make it impossible for them to do anything about a simple problem

Things have changed since the 50's right through to the late 80's,most of what you did back then, does not apply now, if you stay in that mind set you are lost

[handlewanker]

Yes Mac, if you say so.... whatever....let it go so the op can post about his solution to the problem....your constant bickering is a bore old chap.

[mactec54]

Yes Mac, if you say so.... whatever....let it go so the op can post about his solution to the problem....your constant bickering is a bore old chap.

My bickering as you call it, is only a response to your continued, impossible Posts, for anyone other than a experienced hand scraper could do, ( which you are not ), someone has to keep you in check, of your uneducated rants, which others have told you the same thing before

[handlewanker]

Mac...what part of the "let it go" didn't you understand.........LET IT GO MATE........we would like to see the outcome of this problem and how it panned out.....your squabble is of no interest to anyone.

BTW......I am definitely not an experienced scraper.......BUT, I have scraped for a living on many occasions and got paid to do it.....anyone who likes that occupation is a masochist......end of story, all toys put away....go to bed.
Ian.

[ti5m]

Ok well first test part ( first part ever actually) on the CNC mill.

Came out pretty good i think.




And anodized

[Turbo442]

Make sure you leave backlash compensation turned off in Mach while making these gib adjustments. Once you get the gibs where you want, them re-set the back lash in Mach.


Sent from my iPhone using Tapatalk

[ti5m]

Make sure you leave backlash compensation turned off in Mach while making these gib adjustments. Once you get the gibs where you want, them re-set the back lash in Mach.


Sent from my iPhone using Tapatalk

Oh i had it turned on when i was making the adjustments. Thanks for the tip. Will turn it off next time.

[mactec54]

Ok well first test part ( first part ever actually) on the CNC mill.

Came out pretty good i think.




And anodized

Excellent work for your first part, it came out very good, you obvious no what you are doing

If only we could get Handlewanker to make something, on his baby $10,000 cnc mill

[handlewanker]

Old mac......as obnoxious as ever.......I don't have parts to make, but I do have parts designed that I would like to make under CNC control when I get the chance......meanwhile, I like to keep it polished up and well oiled to impress my friends......LOL.

I get amazed looks from them when I casually create and run a batch of hand written G code and watch the wheels go round......circular interpolation is so impressive to watch......some are even thinking of getting into CNC too as it looks so easy.

Good work TI5M.....now you can make lots of chips without worrying about a thou or so.
Ian.

[mactec54]

Old mac......as obnoxious as ever.......I don't have parts to make, but I do have parts designed that I would like to make under CNC control when I get the chance......meanwhile, I like to keep it polished up and well oiled to impress my friends......LOL.

I get amazed looks from them when I casually create and run a batch of hand written G code and watch the wheels go round......circular interpolation is so impressive to watch......some are even thinking of getting into CNC too as it looks so easy.

Ian.

Old Mac that sounds quite good, I could start using that in about 20 years, when I catch up to where you are at, you have been saying you had parts designed for more than a year, I guess we will just have to wait another year or two for the Designed parts to be approved, I believe you will have a birthday coming up when your baby cnc mill will turn ( 2 ), can we have some chips please

What ever happened to all the things you where going to build, and started, we would love to see the progress

[ti5m]

Excellent work for your first part, it came out very good, you obvious no what you are doing

If only we could get Handlewanker to make something, on his baby $10,000 cnc mill

Thanks mactec54,

I just watched a lot of YouTube videos on how to use Fusion 360 and Mach3. Don't really know what i am doing lol.

I still have a bit of a backlash issue you might be able to see in the part on the middle of the curved sections there is a little flat spot. Its where the direction change happens in the Y and X axis. I cant really tune it out with Mach3 as i can get the backlash adjustment set perfect in one spot but then in a different spot it will be out. This is the same on all 3 axis. Good in one spot, and a bit out in others. I know my X axis has tight spots at the ends of travel but this part was machined in the middle of the table where its free so ?

Also my steps per is a bit weird. I can get it set perfect with two 1 2 3 blocks so a distance of 6". but then when i try to step in 0.1mm increments its way out. I have to step 12 times to get to 1.0mm which is strange as it measures the 6" distance spot on.