[COMachineist]

Hi Hoss
I believe ya:-) I kind of just guessed. Not many have access to multi CNC mills like yours and would have to pay some one to do the machining. Plus all the other time on things not directly related to the G0704 but needed to complete all the nice options on your's. Like Lathes to tune the parts, 3d Printers to make little thing like covers, clamps holders making all the parts for the 4th and 5th axis, enclosures getting hardware together, Flood coolant setups. How many versions of each thing have you gone through? If you say only less than 2000 hr I believe you. I don't think anyone less can duplicate you machine for less time and money.
Happy Holidays my friend and thank you for all your contributions to this great little machine.
CH

[hoss2006]

Hi Hoss
I believe ya:-) I kind of just guessed. Not many have access to multi CNC mills like yours and would have to pay some one to do the machining. Plus all the other time on things not directly related to the G0704 but needed to complete all the nice options on your's. Like Lathes to tune the parts, 3d Printers to make little thing like covers, clamps holders making all the parts for the 4th and 5th axis, enclosures getting hardware together, Flood coolant setups. How many versions of each thing have you gone through? If you say only less than 2000 hr I believe you. I don't think anyone less can duplicate you machine for less time and money.
Happy Holidays my friend and thank you for all your contributions to this great little machine.
CH

Yeah I don't think you really do but no matter, it's all there in the threads. When I was working I could manage only a couple hours on weekends but do have more time now. Yes having an equipped shop certainly helps but isn't that what most of us are going for? If someone has a mill and nothing else they are going to be hindered, I know. As far as multi cnc machines, I myself only had the x2 and it got mothballed pretty quickly, besides my disability has kept me from it and most of the other equipment since jan 2011, only this year was I able to get some of it brought upstairs, by then most of the work on the 0704 was done in 2011/12 using the 0704 and the little 7x10 lathe. This stuff doesn't have to be bank or time busters it's more about how you spend it. Well enough of hijacking your thread AVRnj, hope you all have a good holiday.
Hoss

[bjones]

True most don't need more than .001 but when you CNC these machines and you electronics is capable of repeating to even less. A saddle or table that is .0035 out of flatness and parallel there is no way your going to improve that by tightening the gib's. All that does is bind the machine up in some areas, and it lose is in others. Lapping want do it either all that does take off material in all areas and you are still not flat and parallel. I see guys here build elaborate little wonderful machines with flood coolant, enclosures 3,4, and 5 multi axis machines and scrimp on the tolerances of the slides, ways and dovetails. Now if you don't need a 20-40 k CNC that's ok too. But if you look at Hoss's machine, man I bet he has 15K in that beast and almost that in hours. So, I say why not, to each is own. It is funny how so many in the world feel they need to tell others what they need and don't need. If a Hobbyist wants a .0005 or .001 machine I say good for you, That is what freedom is about , right.
Take care and Happy Holidays
CH

I didn't say overtighten the gibs now did i. now when you say .0035 out is that over the length of the table or just the 19 inch travel? a little trig says that instead of 90 degrees the angle of the part you'd machine would be 89.98945 degrees, that is if you clamp to the table, put a part in a vise and who knows. betting you couldn't detect that small difference if you tried, let alone the hobby guys. i think time could be better spent.

Plus none of the castings are stress relieved so they just keep moving over time with age.

so did you heat treat yours to stress relieve it before you did all the work scraping it or do you plan on redoing it every 6 mos.?

[COMachineist]

CH, not a hijack at all, your advice and experience is much appreciated. I am trying to achieve a very high level of precision, and I am willing to go to extremes to get there if needed.

One question I have is regarding the 24" x 24" granite surface plate, if my x axis table is 34" long and my z column is probably longer, can I still use a piece that small?

Do you just do a part of the surface at a time?

I do agree that it is a good thing to have in the shop anyway, and I will have this machine torn apart so I might as well have a look.

Thanks again!

AV
If you can swing the cost a 24X36 or I think they make an 18X36", either will work just fine. My X axis is only 26" so all I had to do was angle corner to corner. It is nice to have as large a surface plate as you can afford or have room for. The 24X24 is just fine for my needs. You need to use it for marking your flatness with the marking fluid I use the water soluble it is nice because it washes off with just soap and water. Richard King sells his Video on E bay or you can reach him by email [email protected] he will help you a lot great guy. He helped me a lot and was very patient with a nub.
I will follow your build with great interest.
CH

[AVRnj]

CH, Thanks.

I found an 18x36 which is reasonable priced on eBay, Grade B, I have a request out for a quote on shipping.

I will definitely look into Richard King and his videos.

I appreciate your help with this.

One question that bjones asked that I would be curious to hear about as well is if you are, or feel the need to heat treat to stress relief so that your scraping lasts longer?

[COMachineist]

CH, Thanks.

I found an 18x36 which is reasonable priced on eBay, Grade B, I have a request out for a quote on shipping.

I will definitely look into Richard King and his videos.

I appreciate your help with this.

One question that bjones asked that I would be curious to hear about as well is if you are, or feel the need to heat treat to stress relief so that your scraping lasts longer?

That surface plate will do just fine. As for stress relief on the castings, the cost will be very expensive. You need to bring the casting to about 1100 F in a heat treat oven with argon atmosphere to reduce scaling then machine, and reheat every thing again to relieve the stress from machining, then scrape for flat, level, and parallel the dovetails. When I made my straight edge from good high quality cast bar(Dura bar 1.75"x3"x24") I had it machined, heat treated then machined to final size, then scraped it flat then gonged (striking it with soft wood mallet) several times. It was flat when I used it and about 2 months later it had warped .002 over the 24" length. So I had to scrape it again.
Happy Holidays
CH

[AVRnj]

That makes sense.

So it is important to keep in mind that this is an ongoing battle, not a one and done deal.

Thanks much for your help and sharing your experiences.

Happy Holidays to you and everyone else as well.

[COMachineist]

Yeah I don't think you really do but no matter, it's all there in the threads. When I was working I could manage only a couple hours on weekends but do have more time now. Yes having an equipped shop certainly helps but isn't that what most of us are going for? If someone has a mill and nothing else they are going to be hindered, I know. As far as multi cnc machines, I myself only had the x2 and it got mothballed pretty quickly, besides my disability has kept me from it and most of the other equipment since jan 2011, only this year was I able to get some of it brought upstairs, by then most of the work on the 0704 was done in 2011/12 using the 0704 and the little 7x10 lathe. This stuff doesn't have to be bank or time busters it's more about how you spend it. Well enough of hijacking your thread AVRnj, hope you all have a good holiday.
Hoss

Hi Hoss
No! I do believe you. Like I said I just guessed, based on the time I have in my simple little machine. Your G0704 is light years nicer than mine. For some reason I thought you had a RF45 that is CNC and I knew you had the X2 from you web sites.
Any way Happy Holidays Hoss.
CH:cheers:

[bjones]

That makes sense.

So it is important to keep in mind that this is an ongoing battle, not a one and done deal.

Thanks much for your help and sharing your experiences.

Happy Holidays to you and everyone else as well.

you could have googled that info too, sounds like a losing battle to me, so does he keep a log of which way it warped after every scrape, you could just be going back and forth every 2 months fixing what you did the last time if it twists back. without heat treatment it's a fools game.

[ChrisAttebery]

Bjones, do you have anything positive to add to the conversation? Every one of your posts comes across as condescending to me.

[COMachineist]

I didn't say overtighten the gibs now did i. now when you say .0035 out is that over the length of the table or just the 19 inch travel? a little trig says that instead of 90 degrees the angle of the part you'd machine would be 89.98945 degrees, that is if you clamp to the table, put a part in a vise and who knows. betting you couldn't detect that small difference if you tried, let alone the hobby guys. i think time could be better spent.


so did you heat treat yours to stress relieve it before you did all the work scraping it or do you plan on redoing it every 6 mos.?

Hi bjones
No the table was out much more than 3.5 thou I had to have Grizzly replace the table casting. The factory table that came with the machine had bad ways on the table.
The bearing surface had bad porosity, as in the machining did not clean up the raw casting in 2 spots. so it was replaced under warranty. The saddle which is 7" on the X bearing way was .0035 out or +.0016 on the left end and -.0016 on the right. I have Starrett indicators .001 .0005, .0001 and mic's are all .0001 I have 1 Brown and Sharpe 2-3 .0001 used to mic the top and bottom ways for parallel.
Never said anything about over tightening gibs I just said you can't adjust an out of square machine into some square by tightening gibs. If the dovetail are not parallel then some where along the axis travel it will bind or get lose.
Yes I did stress relieve my castings I have a mid size PID controlled heat treat oven that I used to harden parts, it is 14" x12"x36" with Argon feed my castings fit easily in it.
:cheers:
CH

[bjones]

Bjones, do you have anything positive to add to the conversation? Every one of your posts comes across as condescending to me.

it's not meant to be but sometimes you have to ask questions that some might not like to answer to get the facts like now we know that the guy recommending scraping didn't mention that he did not heat treat first to relieve stress so any scraping done will be pointless in the long run.

[AVRnj]

Bjones, do you have anything positive to add to the conversation? Every one of your posts comes across as condescending to me.

I personally don't see it as condescending.

I think this is helpful discussion which is all relevant. I appreciate various perspectives from experienced people.

[bjones]

Oh now he's claiming he did heat treat, boy the claims just keep changing. funny you never mentioned that all important step before. so it was the saddle that was out .0035? you haven't mentioned that either, it's been all about the table. so how do you check a part for square using your brown and sharpe .0001 mic? so .0035 in 7 would be .0095 in 19 that would make it 89.97135 degrees, still don't think hobby guys would ever notice such a small difference. sorry but have to go, special get together at church, god bless and all have a merry christmas.

[COMachineist]

Oh now he's claiming he did heat treat, boy the claims just keep changing. funny you never mentioned that all important step before. so it was the saddle that was out .0035? you haven't mentioned that either, it's been all about the table. so how do you check a part for square using your brown and sharpe .0001 mic? so .0035 in 7 would be .0095 in 19 that would make it 89.97135 degrees, still don't think hobby guys would ever notice such a small difference. sorry but have to go, special get together at church, god bless and all have a merry christmas.

If you look at the pix I posted it is the saddle and the readings are written on the saddle at the location they were taken. I'm not recommending anyone scrape a machine. I just wanted to shed a little light on the options that are out there. I don't have a dog in the hunt here jones. I don't try to tell anyone what they should do, or what they need. Everyone here has their own reason for doing a Home CNC. I did my own with the help from others here, Hoss, Zach Chris and Mat to just name a few. I don't know what your background is or your experience level, but you sound like a math major or an Engineer. I'm neither just a hobby home tinker. That has collected some nice tool over the last 40-50 years.
Avrnj, I'll be following your build, good luck. Hope to learn from you as well.
Cheers
CH

[arizonavideo]

My Weiss 30 ran the table with less than .002" flatness. It was better than my IH mill.

I would check all the ways for smooth travel and blue the gib strips and see what the contact area looks like and if all moves well then leave it. To check the gib remove all the oil from the contacting surface then blue the gib and let it rub. The gibs are often done wrong.

I know the grinding might cause a slight warpage but it still leaves a fairly flat surface good enough for hobby use, unless they blew it.

Scraping looks to be a bit of a art and much practice to get good at it.

What kind of parts are you planing on making?

[AVRnj]

My Weiss 30 ran the table with less than .002" flatness. It was better than my IH mill.

I would check all the ways for smooth travel and blue the gib strips and see what the contact area looks like and if all moves well then leave it. To check the gib remove all the oil from the contacting surface then blue the gib and let it rub. The gibs are often done wrong.

I know the grinding might cause a slight warpage but it still leaves a fairly flat surface good enough for hobby use, unless they blew it.

Scraping looks to be a bit of a art and much practice to get good at it.

What kind of parts are you planing on making?

AV, thanks for the tip, I think this is a good strategy as well.

I plan on making mostly precision type aluminum parts, hypocycloid gears, press fit bushing holders, joint hinges, etc.

I actually got some time to play around with the mill yesterday. I through my DTI on it and tested out the table in the X axis direction.

I zero'd in the center. To the left of the table it linearly went up 0.0025", to the left of the table, it was flat to within 0.001" for the majority of the table, and the last 4 " linearly went up 0.005".

Having not taken everything apart yet, it's hard to say whether that is in the table itself, or in the ways.

[wizard]

Oh now he's claiming he did heat treat, boy the claims just keep changing. funny you never mentioned that all important step before.

Heat treat won't stop all movement, that is why good shops have calibration schedules for their reference devices. If not calibrated at least checked regularly. I'm not dismissing the importance of stress relieving a straight edge, however it. Is foolish to believe that once it is done the material will be completely free from distortion. It could take literally years for a piece of castiron to become completely stable.

I know you mean well, but really the need to scrap in a straight edge is not uncommon at all. This especially the case with new cast iron.

so it was the saddle that was out .0035? you haven't mentioned that either, it's been all about the table. so how do you check a part for square using your brown and sharpe .0001 mic? so .0035 in 7 would be .0095 in 19 that would make it 89.97135 degrees, still don't think hobby guys would ever notice such a small difference. sorry but have to go, special get together at church, god bless and all have a merry christmas.

Have a Merry Christmas and a Happy New Year.

[bjones]

Heat treat won't stop all movement, that is why good shops have calibration schedules for their reference devices. If not calibrated at least checked regularly. I'm not dismissing the importance of stress relieving a straight edge, however it. Is foolish to believe that once it is done the material will be completely free from distortion. It could take literally years for a piece of castiron to become completely stable.

I know you mean well, but really the need to scrap in a straight edge is not uncommon at all. This especially the case with new cast iron.


Have a Merry Christmas and a Happy New Year.

i wasn't talking about a straight edge, i was quoting his statement about the machine castings.

Plus none of the castings are stress relieved so they just keep moving over time with age.
CH

which begs one to wonder just how he knows this for a fact, has he visited the factories in person?

It could take literally years for a piece of castiron to become completely stable.

which also begs to ask why these guys expect these machines to be perfect and stay that way when they spend as little as possible on them?

[AVRnj]

Spent some time over the last couple of days breaking down the Mill.

I got stuck on the column as there seems to be something from the base running up to the half nut that holds the head in place that I cannot quite figure out how to remove yet. It seems like it adds support for the large head on this that is not on the G0704. The manual sucks and looks like the exploded parts are from a PM25, and not the 30 that I have which makes tearing it apart a bit challenging at times.

I think I am going to have to go under the bottom of the base to see what is going on under there. My hope is after removing the table that I can tilt it back on its side to get under the base, we will see.

I took the head off, the table off. Both were pretty heavy, the table was surprisingly heavy.

I did not want to rip out the electronics for now to be able to turn the head on its side like Hoss does, so I built a little stand out of 2x4's to hold the head in place while I removed it, and it can stay on its stand while I work on the conversion.

Once I get everything taken apart I hope to order the ballscrews and the electronics, than I plan on figuring out the mounts.

While I am waiting on the ballscrews, I plan to evaluate the contact points in all the ways and see if I need to do any lapping or scraping.