To scrape or to grind worn ways?

I just bought my first CNC mill, its a Webb 10x50 3VH, with a Anilam Crusader 2 controller. The controller is out of date and my plans are to update it. However where as this was an incredible deal I have found (as expected) that the machine is worn due to negligence. As I took it apart I had to literally drill out the oil passages on some portions as they were SOLID with oil and other garbage. There is wear on the outsides of the X axis, and the Y axis GIB is loose to the point that in order to tighten the Y travel the gib must be pressed past the limitations of the adjustment screw. I do not know how to scrape ways, nor do I have the tools or time. My question is would it be better to have the ways ground or scraped? I do not know of anyone in my local area Los Angeles, Temecula, San Diego that scrpaes ways or grinds ways. I know there are a few shops that have larger surface grinders, but I am not sure if this is a reliable way of fixing things. I appreciate your input.


-Shep

Pictures?

Shep,

I suggest you read the thread that I am posting a link to. Another member had similar problems with a Proto Trak machine and the discussion of whether the parts should be ground or scraped was discussed. I know you said you dont have time to do the work but I think you will still get some useful information from the thread. Ironsmiths, solution to his problem is unique and you will not find anyone else who will do the same but it does at least give you an idea of the work involved.

http://www.practicalmachinist.com/v...inspection/trouble-trak-bed-mill-ways-290265/

Charles

i know a couple of one man shop rebuilders in the Bay Area who I would bet could do the job for you. Email me and i will forward your name to them. [email protected] Also there a few weeks ago there was a discussion of a rebuilder with a way grinder in the LA. Schaffer Grinding <> http://www.practicalmachinist.com/v...nspection/west-coast-waygrinding-mail-289022/ Rich

Thanks for all the quick replies. I will look into Schaffer grinding place, i hope that they are at least reasonable. I had read through the Proto track post earlier today while doing the search. I do have a few questions, and I may try to practice the scraping on an old Kent-Owens mill I am working on, but for now I will leave this mill for the pros. Here are the few pics I have right now of the mill, I will take more tomorrow.

It looks like the top of the knee is chrome plated and if there are no scratches in it, that might be OK. The saddle top doesn't have turcite (green wearstrip) on it. So you maybe able to glue on some turcite on there and that could work. What is your plan for the machine? What kind of tolerances are you looking to hold? When your taking more pic's flip the saddle over too. top of knee, gibs, etc. One thing for sure you need to clean the lube system. if you follow the tubes back to a manifold you will see some 'flow control metering units" and they need to be replaced. Seeing it is a Webb, it's Taiwanese and metric. I buy metering units from High Quality Tools, Inc.
and I see they have a store in CA too. Will write more...have a good day. Rich

The bottom side of the Y axis is chromed, and as the pictures show the chrome is worn through in the middle. The damage isn't too bad, there are a few short scratches in the way. The top part of the Y axis (saddle side) is worn with several scratches and scarring. The center relief in the ways on the saddle side are still untouched by the wear pattern, I cannot get a .002 feeler gauge under a straight edge when compared to the rest of the saddle. There is .003 of play from the knee to the saddle when you pull up on the saddle and rock it back and forth, and there is .003 of play when I try to twist (push pull) the saddle on the Y axis. The X axis has irregular wear you can see in the pictures where one side of the table (outside way) still has some signs of flaking, where as the opposite (inside way) does not show any sign of flaking as it is worn through. The table has .005 of play if you twist (push/pull) against the X axis. Both the X and Y gib travel past the limitations of adjustment, and there is binding when the gib is tightened and the table/saddle are moved from center to the outer extents of travel. I am going to call some shops tomorrow to find out if anyone will grind this and how much it will cost to grind this. I am doing all of this on a budget as I am going through the process of medical retirement from the Army and the pay isn't the greatest. If all else fails I guess I am going to have to look into a scraping class or shadowing someone that will teach me. I am looking at standards (straight edges) and they are DAMN expensive. I will post updates as I move along.

I did do some small stuff in the mean time tonight, I worked on the oiling system, getting things cleaned up more. I found the three lines that go from the dist block to the ways do have one way flow controls (thanks for the heads up Richard) . All of which do not allow oil/compressed air/ or anything else through them at this point. I will most likely have to replace them.

The Y axis, knee side:







The Y axis, Saddle side:





X axis, Saddle side;












X axis, table side:

INSIDE EDGE:





OUTSIDE EDGE:



I know this is a lot, but I am hoping that this thread can help those who go through this in the future. It seems as if lazyness has struck again, as a $100.00 way protector set and 15 sec to pump the oiler every day, could have prevented all of this. I hope that I can get away from this with out putting out a ton of money. I appreciate the help!

-Shep

I am not qualified to state that one or another way is bad..
But several people report satisfaction with both grinding and scraping.

Thus, I would expect either can work.
As a manual process scraping can potentially yield a "better" outcome, with high amounts of labour, either yours or someone elses.

A couple of questions Shep, you say you used a straight-edge...is that a scraping straight-edge or a steel rule? The lube fittings or metering units can't be blown out but if clean out the oil reservoir and fill it with mineral spirits or kerosene and pump that though the metering units and they bleed out the solvent slowly it could cleaned out. (new ones also bleed out the oil very slow) The unit has a felt in it and small screens, some even have the check valve, some don't. New ones are around $10.00 - $15.00, I have seen some as low as $8.00 each. One online rip off company in NJ charges $40.00 each so be careful. Look at them and record the number and re oorder them or if you want order the next sized number up as this will allow more oil but could become a mess. There is auto pumps but expensive. Like I said High Quailty parts is fair in the prices on small orders. I also buy from where they order from: LUBE GLOBAL /LUBE CORPORATION Lubrication systems

Be careful when removing them and record the number and where it was, if you all ready did and didn't record the order. Usually there are 2 sizes..or flow rates....the higher ones go to the X & Y ways and small ones to the Z and ball /acme screws.

Do you have a granite surface plate by chance? Looking at the Knee Top chromed ways, to be honest I have seen a whole lot worse and if your not holding .0001's , you might be OK to just scrape and 1/2 moon flake the ways. On average those flake marks you can still see are around .0005 to .001" deep and when we set the gibs you need to have room for oil to cover the ways, so if it has .0005" per side or .001" after a rebuild on CE ways that is OK.

So if your not holding super high spec's you could clean it up, give it some new oil pockets, shim the back side of the gibs and use it until you start making the big bucks. In the Oakland Class we had 2 years ago one of the better students was an MD from someplace north of LA. If you email me I can give you his email address. He could be your tutor as I always ask my students to pass on the knowledge. He has a power scraper, hand scraper, Glendo lapper, straight-edges, etc. The Host of those classes (we have had 3 scraping classes in the Bay area in the last 8 years) also is now rebuilding machines as a couple of others in there spare time. So there are plenty of tutors out there for you.

The chrome on the ways can be lapped a little with a diamond lapping plate (like a stone) to remove any burrs or help with the low center. That is "flashed chrome and under .001" thick. Scraping it is not an option and if you wanted to remove it, I would suggest taking it to a plating shop and they will strip it off. Some use some home made vinegar solution but it is a whole lot easier having a pro do it.

I would guess if you have a pro do the grinding you're looking at $800.00 to $1200.00 minimum. if you have a surface plate you can check the 4 corners as did Iron does in his pro-trak thread. if you don't, there are some cheap ones online or possibly you can buy one off Craigslist. Look for a A grade, B for last resort. A quick check could be done with a micrometer. If you decide to spend some money you should Turcite /Rulon the bottom / top of the saddle and gibs as this will make it a real updated CNC. If you clean up the ball screw, how does it look? Let us know and we can discuss it some more. Rich

PS: Picture is Jim from GA class "Bump" scraping and a student in Taiwan hand 1/2 moon flaking that are pretty easy to do, if someone shows you how, as is scraping for that matter. There are several more pictures in my profile. Click my name then profile and album.

Ultrasonic cleaners work on metering units most of the time. I've had very good luck with the cleaner then hooking it to a hand pump with mineral spirits as richard said.

Well I haven't made any progress yet with the mill, I am looking at this point to just do it myself with the Turcite and all. I found some granite surface plates in my local area for sale. They are B grade but they don't look too bad. The straight edge is appearing to be a little tougher to find. From what I understand it is IMPERATIVE that the straight edge be longer than the piece you are comparing it to. For instance I have a 50" table, I would need a 60" straight edge. Is this true?, this is what I have been told in the past.

-I am thinking that for the saddle (Y axis) I can just flycut the bad area on another mill as little as possible in order to get a good clean surface to adhere to. Then scrape that against the granite plate, once that is scraped I intend to add Turcite to the saddle, then scrape that in. My thoughts are that if I Cut down the saddle then build it back up with the Turcite I can just purchase a replacement gib, scrape the gib in, while remaining at the stock dimensions. As far as the Dove tail I will have to use a straight edge to scrape against. My thoughts on the dovetail for the Knee is Turcite as well.

-The X axis saddle side won't be as bad since I can readily find a surface plate big enough to get a rub off of, the dove tail will of course need a standard. The Table side is where I fear I will have the biggest problem. Like I mentioned I CANNOT find a 60" straight edge that I can afford. I Intend to Turcite the Saddle side of the X but not the table side. Is this the right logic or am I assbackwards?

I would strongly recommend thoroughly cleaning, reassembling, and putting the mill through its paces PRIOR to scraping. Unless you want to do it as a learning experience. You may find the mill cuts adequately to your needs.

IMO with a 50" surface a 48" straight edge will suffice. Typically your master should be at least the same size if not a touch bigger so you are correct, however if your careful it's very easy to get the same results with care, using a slightly shorter master. 50 v's 48 is pretty easy to do, that covers 96% of the part your scraping, no big deal.

Ironsmith: I was thinking the same thing, I just wanted to be sure and get some experienced feedback. I f careful I do not see why it will be a problem, I understand how surface pressure and contact is essentially what causes the removal of blue to leave behind the shiny low spots, and I understand that there is a difference between the surface pressure and contact of a total area vs that of an area with an edge. I know that the edge can possible give me a false rub though the exertion of more pressure via the radius and loading/unloading of pressure on the area in which an object rests. I just didn't know if that tiny fraction of a change should be worth consideration when a rub is established. I do have my assumptions, but they are just that, assumptions. I know that on paper it makes a difference, but a seasoned vet knows more than a bunch of math on a paper ever will tell me. Still though, a 48" straight edge is not much easier to come by, especially considering that I need something and edge with a dovetail.

Fal Grunt: I have the mill all apart and the ways scrubbed clean and re-oiled for protection. I reassembled it and there is a good amount of movement in the ways, not to mention the deep gouges in the bearing surfaces from negligence. I thought this would be a prime time to get this done as I do have a little cash to put towards it and the strong case in which I can argue to my wife to get her to allow me to do it. I just do not wat to get it all back together and start doing work and find out I cannot hold a tolerance because of wear. I don' think it would hurt at this point to update it in the case that I ever have to re-sell the machine.

I do have an additional question that I left out earlier. In the case that I just send the stuff out and have it ground by a reputable grinding shop that specializes in this type of way grinding, will I still have to scrape it in? I know I will have to flake for oiling but will scraping prior to that be necessary if I don't use Turcite? I talked to the guys at Schaffer grinding and they told me to grind both sides of the saddle and the table as well as the dovetails it will cost $800.00 and take 5-7 days. If I have them grind should I still scrape?

Those guys probably have a biax 1/2 moon flaker or know someone locally who does. Grinding would be the way to go. You can afford to spend a few bucks getting it right. You might be able to barter with these guys too. Being a med student you could tell them you would give their employee's a course in CPR or proper ways clean cuts and first aid. Many fire stations have the CPR dummy you can borrow. Also ask them if they can steer you to a good local rebuilder. They will also know about the use of Turcite / Rulon and most modern machines use it to eliminate stick slip. If they grind the ways the gibs will slide in deeper and a easy fix is putting Rulon on the wear side of the gibs. I would also relieve the center 40% of the saddle and gibs .001 to ,002" as described before. Many new machines are not scraped with bluing. They are ground and 1/2 moon flaked. The guys at Schaffer I am sure know this. That's cheap to do the grinding. Rich

Solid with oil, this is a result of people not realizing there are two types of way oil, one is for brush application (Vactra 1) the others are for lubricators, ( Vactra2) many oils are not compatible, some synthetics will jell when mixed with petro based oils, tag resevoirs with the only oil to be used.