[daconfusion]

Hello,

I am in the process of retrofitting my new G0704 to CNC. Just waiting on the brackets to mount everything up.

I noticed that the ways of the table (which contact the saddle) seem quite rough. Attached are pictures. Please let me know if they need attention either by me (newbie) or if they need Grizzly to address if out of spec. Also, I am open to having a service (professional) improve them.

I will follow up with a second post that has the base ways pictured.

[daconfusion]

Here is the base (attached). I can see machining but it is smooth to the touch.

[arizonavideo]

On the table the ways do not look that bad. The bottom of the dovetails don't touch so the finish is not important.

I would install the carriage on the table and see how it fits and moves. Look at the Gib strip closely. Vary likely it will need work to fit properly.

If the table has ruff spots a sanding block is OK to remove high spots only. Low spots should not matter.

[Fastest1]

Quit over analyzing this process. Sure you can micro manage every aspect and find issues. This is your first machine. It will take a while to understand the relationships of the pieces.

Do you have a criteria you are trying to meet? Are you expecting tolerances within .001? If so, you wont get it with a Chinese budget machine. On the other hand maybe you arent familiar with just how small say .005" is? Pull out some feeler gauges and see just how small it is and if you could live with a difference of that much.

Too many times on this and other forums people with little experience are shooting for unrealistic goals because they saw or read that someone else achieved it. Sometimes those others have years if not decades of machining experience. They understand tool wear, fixturing, tool paths and how to compensate for their machines. You will not learn this purely from reading.

Watching people on YouTube such as Hoss or Tryally is not the norm. These are people who are highly skilled showing you their skills and accomplishments. This is a profession to many and it requires an education, whether it be formal or not.

Your machine looks fine IMO.

[Fastest1]

On the table the ways do not look that bad. The bottom of the dovetails don't touch so the finish is not important.

I would install the carriage on the table and see how it fits and moves. Look at the Gib strip closely. Vary likely it will need work to fit properly.

If the table has ruff spots a sanding block is OK to remove high spots only. Low spots should not matter.

Though I agree with AV on the principle of his statement. I think this early in the game for you, it could cause damage to your machine if you sanded something not understanding the relationship of the parts.

I am not knocking you or your abilities, just a warning. The machine will work well if you just bolt all of the parts together carefully. Then if something isnt to your liking, pull it apart and improve it. You will be taking this machine apart more than once, believe me.

[CL_MotoTech]

My advice would be to stop sweating the small stuff. Get the machine working and when you find deficiencyies correct them. It's easy to worry about things that in reality are not going to change much.

[daconfusion]

I don't think my initial images captured my main concern. (I am worried about surface contact wear due to rough surfaces, I don't have any delusions of trying to hold a part .010 in flat over full axis travel)

Yes, I am inexperienced at machining. But I have an okay understanding of surface contact. For manual mills it wont be as critical, and at extreme ends of travel, also not as critical. I also have a basic understanding of effects of lubrication and bearings. While I was cleaning the contact surface with a microfiber cloth, it kept getting caught on rough spots. In particular, the area shown in the image below. I would think the roughness of two contact surfaces should be similar.

In my mind, rapid travel from CNC movement will significantly increase wear. Especially since I am not following the unique users of adding lubrication paths at phase 0. So I don't think I am over analyzing if I want to consider due diligence while the machine is in pieces.

But I have been accused of over-analyzing stuff at work so...you're probably right.

I do appreciate the feedback. I will see how the travel feels and go from there.

Attachment 346958

[capocoreyollo]

I just spent a half a year hand scrapping my mill...boy was that a project! But what did I find in the process? While pretty rough, the ways REALLY aren't that bad from an alignment stand point and that rough finish helps maintain your oil. If you want to do anything, just take a a good stone and de-burr the ways, CLEAN IT!, oil it up really good and put it back together.

I would definitely recommend a lubrication system, especially if your going CNC. With proper lubrication, by the time your ways wear enough to start galling, you should be better equipped to handle the situation by ether scrapping it or milling the dovetails off and going with linear guides.

If your new to machining, it'll benefit you in the long run to learn on a less-adequate machine anyway. Its your first machine, make some mistakes and learn a little.
Corey

[109jb]

On my G0704 the ays look much like the pictures shown here. All I did was a little de-burring and a little lapping on the X and Y. I don't want to get into a debate about the pros and cons of lapping vs scraping. There is plenty to read on that debate in other threads. Suffice it to say I elected to lap primarily because I wanted to do something quick and not spend a long time on it. I only did about 50-75 strokes using a pretty fine grit lapping compound, so very very little metal was removed. This worked well for the X and Y.

The Z axis is another story. I found that the dovetail was tight at the top end and looser in the middle where the cutout is. I attribute this to machining of the casting before sufficient resting after casting. In any case what I did to combat this was to take a fine file, grind one edge of the file off at an angle so I could get into the corner, and I filed the dovetail while measuring the width using 2 dowel pins and a micrometer. Once I got it very close I lapped the whole Z-axis. I know it sounds bad to take a file to a dovetail, but I reasoned that the top end is just where the Z slide goes when homing, or to clear a tool for a tool change. It is very very seldom that any actual machining would happen with the slide that high. The only exception is drilling operations are sometimes getting up there in height, but it hasn't been a problem. My primary concern was therefore to eliminate binding at the top so the gib adjustment would not have to be loose at lower heights. I did do my best to make it even, smooth etc. This worked pretty darn well and I have had no issues having done this.

Having said all this, I would start out by checking how smooth the operation is with the gibs adjusted properly before doing anything and if there isn't any binding or rough spots, just leave it alone.

[Fastest1]

Though it would be better to have a lubrication system. It is quite easy to squirt everything down with lube before and during machining. An oil can with a flexible hose does the trick quite well. I squirt the ball screws too.

Doing your due diligence is an asset no doubt. There is just so much information, it can be crippling.

[capocoreyollo]

If you decide to lap it, just make sure you use non-embedding lapping compound. You want the stuff that washes out or breaks down, some compounds will embed in your ways and never break down, essentially lapping your machine forever untill you machine or scrape it out.

[arizonavideo]

Its best not to lap.It will almost always give you a non flat surface.

I use a strip of 320 sand paper cut to fit the inside of a dove tail with sticky on the back slide like the Y slide. A few passes will remove a high spot and still be guided by 3 reference points. The dovetails look to be the most common rail to be non parallel.

I would leave the flats alone except a quick light pass with some 500 grit on a flat block to remove high spots.

Some day I will do a video of removing the high spots like this. It works well and does not cause the flats to bow like lapping.

[daconfusion]

Here is the base (attached). I can see machining but it is smooth to the touch.

I've been working with Dave (ArizonaVideo) to install his cnc kit. I had significant issues installing the y ball nut assembly. It kept rubbing in the base and I had to dremel through base just so the y nut could fall low enough to pass the saddle over.

I'll post measurements of my y pocket but I wanted to see if anyone can notice a significant difference from the quoted images.

Looking at others g0704 mills it seems that my y pocket is much more narrow. I'm not sure if others had machined theirs. The third image shows the hole reamed out to 1.25 inches to help me with install. I didn't do a great job with it. I'll be grinding the top to help with clearance to double nut.

The mill was purchased last month brand new from Grizzly. Dave and I noticed that my saddle did not have a shallow pocket so there have been noticeable differences so far.

[arizonavideo]

For comparison my slot on the Y axes is 1.87" at the front and 1.885" at the rear.

[daconfusion]

I tried to measure the bottom opening width. It was not easy...about 1.464" wide at bottom near cross-member. The top of the pocket: 1.902" at front, 1.962" middle and 1.938" at rear of Y axis pocket.

The interference zone is at the bottom opening.