[skullworks]

I wish MY IH mill had ground ways.

That IS the way they are advertised on the IH website, it appears however that the asian supplier never got the memo. Mine arrived with just crude machining of the ways, nothing ground but the table top and side.

Had I seen it that way on the truck it would have never been off loaded, but I was not there when it was delivered. ( The Y axis ways were visable thru the missing portion of the shipping crate. The DRO box only made it because its tape stuck to some of the crates tar paper lining - 1/3 of the crates floor was missing. )

[IHCNC]

Hi Greg;
You bought the mill and DRO in 03/17/2007. At the time you told me about the crate, but said everything was fine and that you loved the mill. After a year and a half of owning the mill if you are not happy with something please feel free to call. As always we will try to help our customers out any way we can.

[Dr Not]

Well I have to say that this is one of the more interesting, and certainly information packed threads that I have read on CNC Zone.

Now I will pick my New IH Mill up tomorrow morning and I am expecting the ways to be ground as is advertised on the IH website. However, after reading some of the posts here it makes me wonder if ways that are ground are ready to begin work. If it is necessary to scrap the machine or lap the ways before even putting it into service.

If Gene or Tommy from IH could comment about this it may give me clearer direction. Well for that matter if anyone could clear up the question about ground ways either needing improvement by lapping or by scrapping before putting the machine into service then I would be very appreciative.

[LUCKY13]

You want have anything to worry with on the new mills. Clean it (all the shipping grease/wax) and lube/oil it.



Scraping is someth8ing that should be done by a profesional anyway. Although many have went through the trouble to learn how to scrape a machine, it is something that if not done right can/will ruin a good machine. Now after you wear your machine out (many years of hard work), scraping would be a good way to repair it.



With the hardened and ground ways of todays IH mill it is ready to rock when you get it (except for cleaning & oiling & ajustments).

Lapping is something that helped the older machines. And although many statements are correct in this thread, when done right, lapping/polishing the ways on the "older machines" was something that helped, and was not a danger when done right. The ways on the newer machines are good enough they dont need anything in the order of reworking.

Get it, clean it, set it up, and enjoy it.


Jess

[MikeAber]

[QUOTE=Dr Not;530938]Well I have to say that this is one of the more interesting, and certainly information packed threads that I have read on CNC Zone.

Now I will pick my New IH Mill up tomorrow morning and I am expecting the ways to be ground as is advertised on the IH website. However, after reading some of the posts here it makes me wonder if ways that are ground are ready to begin work. If it is necessary to scrap the machine or lap the ways before even putting it into service. QUOTE]

New machines are much improved compared to my 8 year old machine and shouldn't require anything other than proper maintenance.

Enjoy,

MikeAber

[Cruiser]

RELAX DR ! Most of this stuff is old mat'l and obsolite with the new machines. My understanding is the new machine was ground on a new machine and that the work on them was up to par at least.
I am refering to the new 12"z model, mine is the 10"z ver 3 and it needed lapping to make up for a machine that milled it allong with many thousands of other parts and never had any maintanance. I would venture a guess that the operators also ran the cutters till they glowed in the daylight ~ and quality control was two words they have had to learn but they didn't know why.
there are lots of old machines floating around and many people have been looking here and asking questions so this was brought to the header for them. It should be trimmed of all the excess chat and just leave a solid info base with bold titles so non of this is confused with the new machine. I WISH I HAD ONE OF THE NEW 12"Z's !

[Freddy Warbird]

I don't see how a man could maintain his sanity if this was his life. Damm.. that is a big area to cover, then move on to the next one. Maybe this is an apprenticeship, and this fellow will move on to other tasks after some time..Interesting skill though.
[ame="http://www.youtube.com/watch?v=2HvEw5k09R8"]YouTube - Kitamura Machinery - Hand Scraping Techniques on a Horizontal Machining Center[/ame]

[BlackMoon]

Amazeing video I allways wanted to see how its done! so thats how that pattren is made I thought it was like the grain of the cast iron or something.

LUCKY13: I don't believe (or heard anyone else say anything about) the ways being hardened. only the gears are hardened

Also, I discovered that the *bottom* way of the table itself is NOT ground.
All other ways are however. the *cough* person who got me my IH clone mill is seeing if he can get me a fully ground table however, and is asking the company to fully grind his tables for the future.

[pete from TN]

So is that long odd looking block he slides across the surface applying some kinda layout fluid to show the high spots? I see obviously how he is scraping to the blue areas I think but that video makes it seem simpler than I thought it was. There must be some master guage that they use to verify flatness no? neat to see someone actually doing it tho... peace

[ihavenofish]

So is that long odd looking block he slides across the surface applying some kinda layout fluid to show the high spots? I see obviously how he is scraping to the blue areas I think but that video makes it seem simpler than I thought it was. There must be some master guage that they use to verify flatness no? neat to see someone actually doing it tho... peace

the block he rubs accross the surface is the master guage. its coated with blue, and it rubs off onto the high spots on the bed.

its a somewhat localized method, so they probably use something to guage overall flatness.. perhaps lasers.

[Cruiser]

I'd bet this machine had been ground, and the scraping is for oil retention. There would be a standard off the side somewhere that had a thin coat of prushion or high spot blue rolled out fine, The blue is non drying and stays for as long as needed, then the Hand (person doing scraping) applies his straight edge (tool in hand) to standard to pick up a fine smear of blue. It is then run on machine to blue the highlites, then the highlites are scraped off for the pattern. When done the blue should be very even and show pattern in a very uniform spread over the whole of surface. I doubt that what this person is doing would satisfy an old school master Hand. but it gets the job done.

http://en.wikipedia.org/wiki/Hand_scraper

[Javerh]

This is a very interesting thread.

the block he rubs accross the surface is the master guage. its coated with blue, and it rubs off onto the high spots on the bed.

its a somewhat localized method, so they probably use something to guage overall flatness.. perhaps lasers.

I ran across this interesting site:
http://www.yasda.co.jp/la_English/takumi/takumi02.htm

The pictures are in a strange order, but I think I understood the process. They start by grinding the way guide. It is then lapped with diamond paste. Then it is scraped flat. Finally, the angle of the surface relative to other surfaces is checked with an autocollimator. If the angle is sub par, the scraping is redone to improve perpendicularity.

A quick check on ebay shows that autocollimators cost something like $200 to $1000. It seems this kind of an instrument could be extremely useful in inspecting the ways on a mill or even tramming the head! Has anybody got experience in using these?

[Mcgyver]

I'd bet this machine had been ground, and the scraping is for oil retention. There would be a standard off the side somewhere that had a thin coat of prushion or high spot blue rolled out fine, ]

no way that is oil retention or what's called frosting, its too deep. Prussian blue is what you thinking of. What would satisfy an old master was the number of bearing points per square inch. The only thing I argue is that the spotting tool is a small...should be most of the size of area being scraped

reading these last few pages, I'm struck by the number of comments and opinions proffered on lapping and scraping done so without the benefit of experience .

I've a a surface grinder but will often do gauge work by hand via scraping - i'll go so far as to say it is often easier achieve a higher level of accuracy with scraping. So far as machine tools are concerned, i think you're deluding yourself that because the surface is ground its either accurate of better than scraped. There is no guarantee a ground surface is flat and besides, flat is the easy part....its getting all the surfaces in the correct relative relationship to one another that is difficult....that doesn't rely on the accuracy of the grinder that relies the accuracy of the set up and operator.

Scraping is a simple skill that will greatly increase your capabilities; well worth learning. for fun, here's a few recent projects.

This is a toolmakers cube square and parallel all over to a tenth. Do you know how to grind it that with just a mag chuck? I do and i've got the grinder....but I can get it as good or better with scraping....and probably faster





Here are some V gauges...gauges instead of blocks . yeah we've all got tons on V blocks but these were made to fit a specific V way and are matched such that 10ths indicator doesn't move on any of the 4 sides with its sitting at 45 on a sine bar. Custom size is one reason for making and scraped vs grind has the advantage that grind surfaces make terrible spotting tools



ground up T&CG restoration...scraping the saddle. this Taiwan Chevalier was out over 2thou on the long saddle V ways....thats not wear its poor construction. You can grind one side of one V flat....and then start puzzling on how your going to get the 2nd 3rd and 4th in the perfect relationship to the first. That's up the operator or set up man and will have nothing to do with the accuracy of the grinder. Like any form of fine bench fitting, tough for Chinese/Taiwan low cost production to compete with what i can do at that bench so far as accuracy and quality is concerned. Perhaps accuracy has improved, but its nonsense to conclude that because the surface is ground, the bearing surfaces are accurate and well fit to one another




double V ways are tricky. The matched blocks are used to check the angle on each V and then used in pairs with a master precision level to make sure one isn't going up hill to the other, and then on each V with indicator set up to measure the distance between the V's, ie no converging



Set up for measuring distance between V's. that's a tenths indicator, took lots of practice to get consistent readings with such a flimsy set up




Anyway, I threw those up to give some ideas and comments from one who actually has done a lot of scraping

[ViperTX]

Thanks McGyver....that was very educational.

You should think about doing a video on a small project. I think that it would be quite educational, you might also be able to make a few bucks from it.

Thanks,
Paul

[grf]

i am new in the forum and also in the machining hobby. i recently bought a machine (bigger than i should) and try to find my way around.

i never thought that even today things would be done in such a traditional way (scraping). i would imagine that by today some sort of hitech solution would be found to deal with these things. it is at least amazing that a flat surface is constructed in such a way.

i have a question though if it is not out of topic. since there is a lot of talking about bearing surfaces wouldnt it be easier or better or maintenance free (or easier) to convert to linear bearings? where i work there is a big cnc (for woodwork) and everything on it moves on linear bearings so it make me wonder. is there a reason that they are not used (apart from cost maybe)?

again great thread highly educative.

[Javerh]

grf, telescope mirrors and lenses can be polished and squared on atomic level. The resulting surface is near perfect. However, the cost of the operation is mind boggling. Furthermore, a guideway made in this fashion would require further work to improve oil retention. Scraping is the cheapest, fastest way to straighten a surface without ruining the oil pockets. I read somewhere, that there have been attempts at making a CNC scraping machine. It would use machine vision and dye applicator to replace the hand. I doubt such a machine would be very versatile.

Linear bearings are superior to box ways in almost every way. They are easier to implement and allow the use of higher speeds. Apparently, their greatest weakness is their dynamic stiffness. On linear bearing surfaces the loads are carried by very small portions of the rolling elements. There is very little oil between the load bearing parts. The rolling elements are very rigid and have only minuscule deflection. On box ways the contact area is larger and the oil layer is thicker. The result is similar amount of deflection. When the ways start to vibrate, a thicker layer of oil can dampen the vibrations faster. Linear bearings will ring out longer. Vibration can shorten tool life, reduce surface accuracy and increase surface roughness.

[grf]

so if i go it correct linear bearings would make the trick but they would fail sooner under lets say heavy loads or during a crash or something like that compared to a dovetail or boxway. what is the difference between the boxways and the dovetail ones? i searched the net but the results are not very clear they look like a square (a plane surface and two parallel for alignment)is this correct?

thank you for your replies. this forum is very helpful

[Mcgyver]

i never thought that even today things would be done in such a traditional way (scraping). i would imagine that by today some sort of hitech solution would be found to deal with these things. it is at least amazing that a flat surface is constructed in such a way.
.

That premise is flawed - that somehow if it hasn't been developed in the last 50 years its no good. There are other ways of getting this flat, some old, some new....in eveluating them or observing their merits there is no best before date. Turning's traditional but is still used, right? It works. the advantage scraping has is that's its comparative; distribute one known quality master and hundreds almost-as-flat copies can be made....all from a low tech, low cost reference flat.

the other thing to appreciate is that getting something quite flat is not trivial, for a given flatness, the bigger/longer the area the more difficult it becomes. Maybe there is a cheap, better high tech way of going about it.... waiting for you to invent it

i have a question though if it is not out of topic. since there is a lot of talking about bearing surfaces wouldn't it be easier or better or maintenance free (or easier) to convert to linear bearings?

On what do the linear bearings sit on? Does that surface not need to be exceptionally flat? how are you going to get it so?

I lack expertise to do a decent treatment of comparing the two, however a few obvious things must be: cost (creating precision bearing surfaces is far from free, I'm not sure which way wins the cost war). Probably more important is loading and rigidity. Other things being equal, I'd think there is an advantage in the large bearing surface a box/dovetail/V way offers vs the very small area of contact recirculating balls offer. Anecdotally I see things like high end jig borers (is there a more expensive/exact machine tool?) with scraped ways not linear bearings....like all design, it depends on what the machine is called upon to do

[BobWarfield]

On what do the linear bearings sit on? Does that surface not need to be exceptionally flat? how are you going to get it so?

I lack expertise to do a decent treatment of comparing the two, however a few obvious things must be: cost (creating precision bearing surfaces is far from free, I'm not sure which way wins the cost war). Probably more important is loading and rigidity. Other things being equal, I'd think there is an advantage in the large bearing surface a box/dovetail/V way offers vs the very small area of contact recirculating balls offer. Anecdotally I see things like high end jig borers (is there a more expensive/exact machine tool?) with scraped ways not linear bearings....like all design, it depends on what the machine is called upon to do

Linear bearings don't have to sit on scraped surfaces. They will perform well enough even on milled surfaces though ground would be better.

If greater accuracy is desired for their mounting (or for creation of any precision surface), there are methods involving poured confections that also work as an alternative to scraping. The issue will be wear, so even though you see machines with Turcite ways, there are disadvantages. OTOH, the Kitamura video looks like he is scraping a column mounting point, so wear issues would be minimal to use the technology there, just as it would to mount linear guide rails.

For really heavy hogging, the box ways are still unequaled by linear bearings. However, most of the lower end of the market has gone to linear bearings, which tells you where the lower costs lie.

It's interesting just how much technology and effort has been expended to help overcome the limitations. High Speed Machining in some sense is all about making lighter machines with linear ways perform at material removal rates more similar to the old school hogging counterparts. For the most part, the battle was won, though the religious arguments still rage, and there is a scale where the linears still can't compete.

Not clear the high end jig borers of old have much on CNC of today. It's one reason they're not very prevalent any more.

Cheers,

BW

[grf]

i am not trying to open another "war", never said it is not a good technique (i am in new in this field in total). i am truly surprised that this technique is still here and from what i see even in mass produced machines. usually most things now days change for the sake of change. i understood the significance of the process but if you saw to someone(without knowledge) the video and you say this is very expensive and precise machine they would look at you strange. people would expect lasers and other fancy stuff.

i think i should stop before the tread gets out of topic because of me.
thank you all for your input to my questions.

ps
Happy new year to everybody