Scraping a Bridgeport
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- เผยแพร่เมื่อ 25 ส.ค. 2024
- This was a winter project for me last year. I rebuilt this mill for a good friend of mine as a gift for all he has taught me in my early years of machining. I am not presenting this video as a how to on rebuilding a Bridgeport but simply as a show and tell of my own process and techniques. I didn't receive my new camera until part way through the project so some pics and vids may be lesser quality. This video is approximately 75% of the process, if you think something was missing in the process, trust me it was done, it just wasn't recorded. I had to keep a schedule for completion so some steps went un-documented, I apologize for this. I hope you enjoy the video and if you like it please subscribe. Thank you, and God Bless.
![[TH]FFWS SEA 2024 Fall - Knockout Stage Day 5](http://i.ytimg.com/vi/N2tl9xkQyyU/mqdefault.jpg)
You are a credit to yourself and those from whom you have learnt your skills. Very impressive and thanks for sharing. All the best Mat
lookcreations Thank you Mat!
Nicely done, thanks for taking the time to share with us your project. I have heard of the peening from Richard but have never seen it so the little you showed is helpful.
Great job Chris! Thanks for sharing your work and craftsmanship. Daryl
Pretty neat, people don't understand that this is more accurate for a flat surface than grinding by machine.
1-Shot slinger Thank you! I run into that argument with people all the time, you just have to do it to understand. I tell them to go and look at the ways on their grinder, gets em everytime.
Uh... Man what a task! I have a 58 j head BP that I have disassembled and electrolysis cleaned every part... That took a year. Now there is this... At least u have shown me that it can still be done. Great vid, thanks for sharing!
thank you!
for anyone surfing scraping videos, this one is the real deal!
lo felicito muy buen trabajo! Saludos de mar del plata , Argentina.
Awesome result! Thank you for sharing
Great work; machine rebuilding art
This was an amazing job! I had the opportunity to take a scraping class from Forest Eady, and learned a lot. Mostly what I learned is that I am lousy at scraping. :) It takes a strong and skilled hand to scrap! Having tried it, I really admire your talent!
davidjh7 Thank you! it's a lost art and rare are those who can appreciate it.
Well done sir.
Nice job young man!
Well done. Beautiful work.
Fantastic work. That is a skill I would love to learn.
You are one who loves his Bridgeport I have my own Little shop thanks for the education .
Awsome work! Fun to watch
Nice looking work Chris. Thanks for the plug on my classes. Some of my students have done some video's on them here. I wish they had YT a few years ago. People can Google my name for info. But Chris is a good rebuilder and scraper I will enjoy watching them from now on. We also write on Practical Machinist forum. Rich
Thanks Rich!
I apprenticed as a machine tool fitter in the early nineties and regreted it as the final pay was half that of a plumber which made me bitter so its nice to see the trade promoted by yourself and youtube
Wow! Impressive. Nice job
Nice job !!!! congratulations from France ;-)
Wow amazing work.
Joe Smith thank you!
How long did this take you?
Joe Smith I just worked on it every Saturday for about two and a half months
Hand of the master
Awesome job
Fantastic work!
Nicely Done. Find an apprentice, as this talent needs to be conserved.
Sorry they pulled your audio feed. Still, I recognized Richard's techniques immediately after taking his class this past week. Nice work--I appreciate how much work that is now!
Thomas Utley Thank you for your compliments. I've never met Richard yet or taken a class, I would sure like to before he retires!
cgprecision Really?!?! I saw Richard's comment below the video and just assumed you had taken his course. Now I'm even more impressed! Wow.
cgprecision Check out Keith Rucker's video just posted today. His is the first of what is likely to be several posted in the coming days of Richard's latest class at Keith's shop in Georgia.
Thomas Utley I will, I enjoy Keith's channel, I'm jealous you got to meet him, seems like a great humble guy and very knowledgeable.
Richard and I have agreed our German lineage must bear on our technique as our methods are so similar yet we've never met, shame as we live only four hours apart. I've been rebuilding close to ten years and I've yet to see another man scrape in person. It's an obsolete trade where I live. Good luck with your class!
cgprecision Keith's building a list for another class with Richard in the fall, FYI. Should be about $1650 class fee plus travel expenses to Tifton, GA. Could be one of Richard's final classes the way he was talking this week. Food for thought...
Thanks for sharing this. I am going to get a used Bridgeport soon and I don't know if I should buy a rebuilt one, or buy one to rebuild. I've scraped small items, but never anything this large. I'd have to buy a much bigger surface plate and a camelback. That's probably $700 right there, although I could resell the camelback after I used it. Then there would be the many hours of scraping. I'm probably not as good as you are, so it would take me much longer. Decisions, decisions... Well, now I've seen it done (and done beautifully).
Thank you for the comments, I would say if you've only ever scraped for flatness don't rebuild a machine of this size yet, practice correcting squareness, dovetail parallelism, gib scraping and flaking on something much smaller. You'll learn much faster that way. If your already well versed in scraping for geometry, and you have the time, then I say dive in, it's a great way to learn.
Buy a really good Bridgeport or a rebuilt one. if you buy ether, learn how to measure what needs to be measured to verify what shape it is in BEFORE YOU BUY. I thought I got a good deal on a 1961 Bridgeport without head for six hundred. It is so bad it is almost laughable but it will have to do until I can afford something better.
Great video!!!
How does the machine feel after all that work? What would an operator notice? Great job.
scott black Well scraped ways have the advantage that they maintain oil throughout the entire mating surface of the machines travel. And since it's a broken up surface unlike a ground finish, you don't get the excess drag like two gauge blocks wringing together. It moves very freely yet it's still a very tight machine, you'd just have to feel it for yourself.
Very good work! The assembled mill is a real beauty; that is a real gift to your friend.
Jim Zuccaro thank you, and God bless.
молодец!!!
Hi Chris. Watched your video again and was very impressed. How did you learn your skills? Are there particular schools available to learn this particular art? I've viewed practically every scraping video all over TH-cam and found them very informational but still have many questions in terms of the proper steps and procedures to follow in order to do a project like this correctly. What could you recommend in terms of books, courses and schools?
+Serenissima3 Thanks for your compliments. I am entirely self taught, I have a degree in tool and die making/machining, and work as a machinist. I also handle some rebuilding tasks at work which is where I learn most of my skills. Richard King gives classes, I've never taken one but have seen and heard of his teaching and I believe he is very reputable and good. There are only a handful of books and videos and I own most of them, although I would only recommend Richards video for learning, also Ed Connelly wrote a book called Machine Tool Reconditioning and Scraping, it covers many basics and is still available through amazon and some other distributors online. My advice is read the books and watch the videos to lay the groundwork, but in the end this is a skill that takes many hours of personal one on one practice and training to learn, buy a small surface plate of cast iron and a sandvik, Anderson or Biax hand scraper and practice, practice, practice. Also keep your eyes on the practical machinist reconditioning forum, great place to learn. Good luck and God Bless.
Audio has been removed... ANY chance on possibly editing video and adding audio back in minus the music that caused TH-cam to kill the audio?
PS: What was the music/ artist who complained about the music?
WeAreNotAlone69
I don't think there was an artist complaining, it was just an automatic you tube system that rejects any non copy righted music. The reason I had the music is the original audio is so polluted with people talking in the background, you can barely hear what I'm doing.
I really enjoyed watching your video (even without sound)! That is such a giant project but I'm sure well worth the effort when finished. Can you explain the peening process for straightening the work?
Leading Edge Industrial - LEI TV Thank you! It is a very accurate machine and I get many compliments on its appearance, it looks much nicer in person!
Leading Edge Industrial - LEI TV Just saw your question about peening. Peening is the art of stretching metal superficially (at the surface) to cause the part to curl. In this case, a mill table, many years of use, (tightening T-nuts and bangs and bruises of the table top) have caused the top surface to elongate and since the underside is un-peened virgin metal, it's not elongated, the resulting effect is the table curls like a banana, high in the middle and low on the ends. The peening I show in the video is on the underside and the goal is to superficially stretch the bottom layer of metal to match the tops condition, this helps cancel out the curl. It's important to rough surface the top before peening the bottom, as cutting the top relieves some stress, if you peen the bottom before hand then cut the top, this will relieve stress and it will over curl and you'll end up with a soup bowl. My process is to rough scrape the top, (or before you tear down the machine, mill .005 off, if it's capable like a bridgeport is) then rough scrape the bottom table ways ( this removes any stress from both surfaces) then peen table straight on the webbed surface underneath, then finish scrape the top, then finish scrape the ways. By removing the outer stress filled skin on both surfaces (top and bottom) you won't have any surprises when you start finish scraping. It's an in depth process but not impossible, you just have to understand the forces at work. There are machines I've rebuilt at work years ago using peening which are still dead straight. One advantage to rebuilding an older machine like this, is once a table has been peened from use on its top like this one had, and then corrected during rebuilding, it usually stays straight longer as the top and T slots are work hardened so it's less likely to move again in the future, call it "seasoned" if you will. I hope I've answered your question and not confused you! God bless and happy scraping!
Thanks for taking the time to explain the process. I've been in manufacturing and I learn something new everyday it seems. The work you do is fantastic!
Super job on the mill rescrape. I especially like that you didn't go crazy with the half moon flaking, it looks good with just the scraped surfaces. I think Richard is right on with his thoughts on where to flake. Is the granite square an import? If it is what brand and are you happy with the accuracy of it?
Thanks Ron, yes the granite square is a Shars import. I have been very happy with it, nice thing about squares is you can use reversal methods to inspect their accuracy, and I have found this one to be less than .0001 in squareness over 15"
Great video, a little heroic music would have been nice.
The mill came out good Chris. Just out of curiosity, approximately how many man hours went into all the scraping that was required to bring the machine into accuracy?
Thanks, I worked on this mill almost every Saturday for about two months straight 60-70 hours approximately
Can I get a quick synopsis of what special tools are required for this process? So far I've gathered:
Dovetail straight edge
Granite angle of at least 15" or whatever s required
Couple large mic's and rolls for parallelism on the dovetails.
Surface plate big enough for the table.
Levels, indicators, stands.
What am I missing?
Max Maruszewski. A few stones, bluing and scrapers also, and most importantly, atleast one year minimum experience scraping basic flat surfaces, and that's if you're a quick learner.
I think picking up a rough casting for a angle plate would be a good place to start, rough mill it and then practice scraping it into a perfect 90. I just picked up an old J head for 1200$ that someone installed grease zerks for the table. I've got about 10 inches of movement before it tightens up on the ends and I'd really like to take on the project of scraping it in myself some day. I think I have a pretty good handle on the geometry of the whole situation, what to reference off of and what the order of operations should be. The angle plate should be a good trial run to pick up the technique and practice scraping for geometry not just flatness. Wish there were more videos out there specific to scraping a knee mill.
Max Maruszewski sounds like a good place to start!
7:20 - What is Peening?
+cgprecision where do you get your tools from, like the scraper and the reference surface?
tester239 the reference surface is a common granite surface plate, available at many suppliers, scrapers are sandvik and mostly home made
Nice job Bro. Nice present. My father from time to time would buy an old machine so we could work on it together. He did't like old cars (ones that needed work, so...) This was his Gig. And it had a bigger ROI than cars.
I think that all apprentices should learn how to do this ... the RIGHT WAY! And not have to fix bad habits.
How long did it take you to flip this job?
par4par72 Thanks for the compliments! I worked on it every Saturday for about two months. I had a total of roughly 70 hours into it.
only 70 hours, a biax does seem to save time
That's a great job, how many hours did it take you ?
Approx. 60hrs.
Dang thats fast!
This...is awesome!
I have an old lathe but what shout i scap first, the bed or the caridge?
The bed is heavy.....reaaaaly heavy!!!
rebuilding is like building a house, you start at the foundation and work your way up, on a lathe you scrape or grind the bed first
So how do you blue such a heavy bed?
+Δημήτρης you would blue a straight edge and rub it to the bed to find the high spots, the nice thing about scraping is its a very portable operation
Does the straight edge has to be longer than the beds lenght or it is ok to be half of it?
+Δημήτρης preferably the same length, you can use shorter straight edges on longer machines with the aid of a precision level, and some special technique, but one of the same length is always ideal
Spectacular work!! Thanks for sharing this with the world... What do you use for a standard/straightedge for the dovetail? I've seen special dovetail standards/straightedges, but I'm not sure if everyone uses them, or if there's another technique.
Once the ways are finish scraped, is there any other preparation or final finishing required? (such as lapping the way surfaces into one another) Or is the scraping itself sufficient?
Thanks again...
JB
WHJeffB Thanks for your compliments, I use a dovetail straightedge for the dovetails. I finish one dovetail and then use a micrometer over gage pins to scrape the second dovetail parallel to the first.
The scraping is a sufficient surface for a slideway, however on some machines I'll assemble the saddle and gibs or what have you to the machine and use a dab of simichrome metal polish mixed with a light oil and run the slides back and forth 10-20 strokes to simulate the initial break in period. It does help to keep the machine in adjustment a little longer I feel. And Simi chrome breaks down into basically nothing rather quickly so it doesn't harm the machine long term.
Thanks for taking the time to reply... I admire the skill and patience you have for doing this kind of work. From the comment exchange above, I see that Richard may be giving only one more class on scraping basics. I've watched a few videos of his training classes and would love to attend, but GA is quite some distance from me.
Years back a purchased a book on machine tool reconditioning with an eye toward taking it up as a hobby (I have machining experience, just not rebuilding experience).
Thanks again for sharing this with the world... I'm very jealous of your friend, it's quite a gift!
cgprecision Thanks for sharing! Could you explain how do you scrape the tapered gibs and dovetails? I understand the straight ones using pins and micrometer to check parallelism but the tapered ones are a mystery to me. Thanks!
Uros Piperski It's quite simple actually, you assemble the two main sliding components, for example, the knee onto the column. Next you blue both interior surfaces, then insert the gib and using a brass punch and a soft blow hammer, gently tap the gib into the pocket, and then back out from the other side. The bluing will transfer to the points of highest contact, you scrape these until your bluing it's entire length. This is a quick description, there are a few more steps but you'll get the basic idea.
cgprecision I think I get it. So I should scrape the dovetails with no regards to the taper angle and then blue the gib to the mating dovetails. And if the gib slides too deep I can add a brass shim to the gib with epoxy adhesive to restore its thickness. Thanks for your time! I hope we can expect a new video soon.
no audio? I'm guessing some cancer algorithm picked up on one of the 3 or 4 songs you were using
HOpefully you can add some audio.
Reupload?
Hi Chris. Phenomenal work! I am planning to improve my Bridgeport and your video really helps. Could you give some info on peening of the table?
What kind of peening chisel ( could not tell from the video) and where on the table do you hit it? Thanks
KN The chisel used was a tapered pin punch with the end ground slightly spherical. As far as where to hit, it's easiest to describe how it works. Peening squashes little areas of metal, your peen mark leaves a shallow divot and the material that once was in the divot gets displaced in all directions. You want to lay your peen marks in rows whenever possible. Run the rows lengthwise as this will counteract the bowing on the tables top. Mill tables always bow lengthwise and never across the width, this is because the T slots act as stress relievers and it never bows the table across the width. However if you measure the t slot width you would see it gets skinnier in the middle of the table. The peening that happens with use on the top moves metal in all directions also but because of the t slots it has no chance to bow the table width wise, only length wise. I usually try to peen the tops of the webbing under the table as this is furthest from the table top thus it has the strongest effect, if you have run rows all down the webbing end for end and it still hasn't moved much you can peen down in the bottoms of the pockets of webbing, but just know, the closer your peening gets to the tables top surface the less effect it will have. You'll notice in the vid that I peened this table width wise over some of the webbing, this opened up the table width wise and the reason I did that was because my dovetails were really wore in the center of travel. By peening them open it saved on how much material I had to scrape off the ends of the dovetails to make them parallel. If you over correct by peening you can grind off the peen marks and it will move back. I would recommend leaving the table sit a few days after peening before you start scraping, this will let all the stresses equalize. Hope this helps. Thanks for the comments!
Chris, really enjoy your videos involving machine rebuilding. Where did you learn these skills? Thanks for taking time to share.
James Shaw Thank you for the kind words. I've had my nose buried in machine tools since I was 12, I guess the majority of my skill set is self learned if I had to point in a direction
copyrighted on the audio. got it without the music?
byrysh I wish, I added music to cover all the talking and background noise, I'm new to this YT thing lol
Chris,
I was curious about your comment "final finish by lapping" on the top surface of the table. Can you please offer some more detail about how you did this? Beautiful job BTW..
This mill was like most other mill tables I've seen, very coarse grainy nudular iron, it scrapes like petrified sheetrock, terrible finish. The lapping was only a means to pretty it up a bit. I only scraped to approximately 10-15 points per inch, before i lapped. The technique itself was simple, I used a very small cast iron surface plate, the same width as the table top. My lapping compound was a 400 grit alum. ox. mold polishing stone crushed to powder and mixed with way oil. I use this over Clover brand lapping compound as Clover is silicon carbide and never breaks down, turning your mill table into an everlasting lap itself. Timesaver is a brand of alum. ox. lapping compound which breaks down nicely but it's spendy and hard to find so I often make my own.
To lap the table I used even figure 8 patterns working my way from one end to the other. Then clean off the top and blue it to the plate to make sure it's even, and keep lapping. I do not add more abrasive though, only oil, this way each time I clean the table, reblue and re oil, my abrasive which was embedded into the plate, became finer and finer until it no longer cut and I had a mirror finish. Hope that all made sense, sorry for the novel!
God Bless
That my you tube friend is a f***ing nice bit of work! Is the Bridgeport yours or was it work?
Jef___ _ Thanks! This mill belongs to a friend of mine.
I hope your friend is still paying for your drinks!
Can this be reuploaded with a good audio track?
ExtantFrodo2
I'm considering it, the actual audio is polluted with people talking in the background tho
cgprecision
Perhaps a transcription for CC then?
ExtantFrodo2 how does one apply for cc transcript?
cgprecision
I don't know. One could always "annotate" the captioning.
Beautiful work! How many times did replacing the leadscrew with ballscrews come to mind? That seems to be the only thing left.
TopLine Automotive Actually I'm not too fond of ballscrews on manual machines, they back feed under load. I've ran some machines like that and you always have to lock the other axes when your cutting to keep them from running away under the cut. If I were going to retro fit servos and cnc control I'd definitely go for it. A nice tight acme screw and nut still holds it own in my opinion. Thank you for the comment.
No audio, can you reupload?
it had audio originally, but it got pulled for copyrights, I'm new to this youtube thing lol
Like the others i compliment you on a job well done. How long did it take you to learn to scrape, and did you take a course or self tought? Thanks Dan.
Thanks for your compliments. I am entirely self taught although I've seen and read the available books and videos, most of my knowledge was learned the hard way. I'd say It took me a good year to learn to scrape, rebuilding machines however, I'm still learning after ten years lol
+cgprecision okay thanks for the information. I figured several years or so.
it's price 142.000$....cheapy