Table way scoring

[MyLilMule]

In the process of tearing down the mill, I discovered some considerable scoring on the left underside of the rearward way. You can feel just how bad this is.

I tried stoning it, but that’s not going to work since I don’t have a stone that could get down into the V. Plus, I think these are just too damn deep.

Now I am going to do some checking around to see who is local to me that can grind them. I sent a message to a place that’s also a sponsor here, but I haven’t heard back.

The mating ways on the saddle are chrome and have flaking. My question is, do the table ways need to be scraped after they are ground?

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[benmychree]

I would scrape the raised burrs and then stone it, you can grind a bevel on a stone to reach the corners, I have a India stone that I use for work such as that, a green grit (silicon carbide) wheel may be best to do the bevel. Sometimes we worry too much about small shortcomings of our machines, when we could be using them instead.

 

[MyLilMule]

I would scrape the raised burrs and then stone it, you can grind a bevel on a stone to reach the corners, I have a India stone that I use for work such as that, a green grit (silicon carbide) wheel may be best to do the bevel. Sometimes we worry too much about small shortcomings of our machines, when we could be using them instead.

I've never scraped before, so I don't even know where to start. I should have prefaced all of this with I am a relative newbie at this as a hobby. I'm smart enough to figure some things out, and smart enough to know I need to know a lot more about different things.

 

[Bob Korves]

Scraping is a substitute for grinding. Both work well, but each works best for specific jobs. Either can do a good job if done right and carefully. It takes some training and practice to be ready to do the kind of work you have in mind. The first thing I would do is finding out what caused the bad scoring on the surface, and see what kind of condition the mating part is in.

 

[MyLilMule]

Scraping is a substitute for grinding. Both work well, but each works best for specific jobs. Either can do a good job if done right and carefully. It takes some training and practice to be ready to do the kind of work you have in mind. The first thing I would do is finding out what caused the bad scoring on the surface, and see what kind of condition the mating part is in.

The mating surface is fine - it's chrome. I suspect a chip got caught under there and did a number on it. No way of knowing since I just bought the mill in April. I just started doing a teardown and rebuild.

 

[Technical Ted]

Sometimes we worry too much about small shortcomings of our machines, when we could be using them instead.

I agree 100% with John on this. We always just joked and said it would help hold the way oil!

I would hit what I could with a stone then reassemble and see if it really presented a problem. Most likely it will work out fine for you. If this machine was going to run 24/7 in a high production environment I might feel differently. But in that situation, a new machine would have most likely been purchased. Replace the felts, keep it clean and well oiled and it will outlast all of us and provide hours and hours of enjoyment!

I wish the ways on my machines were all like new!

Ted

 

[MyLilMule]

Once I get the table back on, I'll sweep an indicator across it (as best I can) and see of there's much of an unexpected deflection. That's my biggest reason for considering anything at all. I like to understand my options, even if when I get there, I don't need them.

Regardless, my original question was, if I choose to have them ground, do I need to scrape them? It doesn't look this table has had any scraping done to it at all in any of the way surfaces, unlike some of the others.

 

[rabler]

I have several older machines, and prefer to fix things that have a noticeable effect to me on the machine operation. Not that I'm opposed to cleaning it up and knowing the condition of the machine, but you can chase perfection endlessly.

My limited understanding, scraping is done for two reasons, one is for very good accuracy, the second is for having some variation in the surface to help with oil retention. If one surface still shows scraping then oil retention is taken care of, and the gouges will retain oil also. Neither scraping or super accuracy is absolutely necessary. Depends on how much accuracy you need from the machine, how much you'll be using it, and if you will keep it long term or eventually replace it. Usually grinding or scraping also means replacing the gib. If you've cleaned it up and stoned the surface a bit (don't try to completely remove the gouges, you're just removing the high spots), then there is little chance of harm in putting it back together and using it to see how it works. Just keep good way wipers on it, and keep it oiled. You can always have it ground/scraped/rebuilt at a later point, especially if you're relatively new and learning.

 

[Technical Ted]

Regardless, my original question was, if I choose to have them ground, do I need to scrape them?.

I didn't try to field that question since I've got no personal experience, only reading and watching YouTubers do it. But, my understanding is that after grinding, the ways get scraped in and then "flaked" which are small semi-swirls scraped into the way surface to create oil pockets. If a lot is removed during grinding, the way surfaces might be built back up with Turkite (sp?). The Turkite is then scraped just like a regular CI way would be. Maybe there are differences when you have chromed ways, I don't know.

Maybe throw up a post in the scraping forum on this list and you'll get some more experienced answers.

Ted

 

[Richard King 2]

I can come here Ted. The OP has to decide how much money he wants to spend and how good he wants the machine to be. If he is a part time hobbyist and use it an hour or two a month then put it back together and use it as is. Replacing the lube fittings (more about that later) . If you want it for 8 hrs a-day and accuracy is important then send the table and saddle out and have it ground and as Ted said Turcite the ways.

I see scored and galled ways a lot when the lube system fails. If it were a chip got in there the scores would not be spread out the entire width. How does the top of the knee look? How about some pictures of the top, bottom of the saddle and the top of the knee. Under the left side under the saddle is an oil manifold with metering units. The Metering units are brass jet devices that meter out small amounts of oil when the pimp is pumped. Or the oil line to that lube hole broke or came out of the hole in the saddle. Pull the table and you can see it, take a photo. Also H&W machine rebuilding has a bunch of You Tube shows on Bridgeport rebuilding. No matter what you do, replace the metering units and clean the oil reservoir. There is aa felt and screens in the pump that need to be cleaned. Use Mobil Vactra 2 way oil too and before you use the machine give the pump a pump. Oh and replace the metering units on the column too. Don't waste your time and try to clean them. We can discuss that too later after you decide what you want to do. The table is peened too, convex on top from years of overtightening the T-nuts. H&W can grind the table or I would reccomend sending the table and saddle to A&D Machine Rebuilding in Roberts WI. I would replace the chrome ways with Turcite. The end of the saddle top will be worn shinny on the ends now I bet? (Oh, I have rebuild several Bridgeport's over the years. I don't guess.