Scraping a Hobby Mill Like a Pro: The Table
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- Опубликовано: 29 июн 2024
- Watch a DIY 5 axis CNC mill project go pro with the help of an expert scraper.
Marcus runs an all-manual machine shop in the Gold Coast of Australia where he does repair work and specialises in scraping! He reached out to offer help on reconditioning the MH28V 5 axis CNC conversion project, and boy DID he help. This episode is all about fixing up the table of the mill.
Attached Article:
www.machsuper.com/articles/scraping-a-hobby-mill-the-table
Instagram:
/ mach_super
Hand Scraping and Machine Rebuilding Aus (Facebook Group):
/ 1242191559496575
In Australia, buy scrapers from PMK Engineering (not affiliated)
/ pmkep
Music Credit:
Let it Go by ItsWatR on Pixabay
Casablanca by SoyB 
Наука
Came here (to the channel) for the harmonic drive, stayed for the scraping. As someone else who learned from Marcus it was great to see so many of these concepts again, makes me want to come back and bring my mill table next time.
Those animations are proper first class, great work! Looking forward to the coming parts.
Cheers buddy! It’s nice to finally put good use to that year at video game school.
Excellent video on scraping. Thank you for your work!
No worries. Glad you enjoyed it.
You need to make a breakdown on how the animation was made, because they are really good!
Thanks Rexus. So far I haven't found a way that I would like to go about that other than writing an article on the website. The channel isn't mean to be about animation so I avoid that idea.
@@machsuper The animations you made were super helpful to understand how scraping works. I also would like to learn how they were done. An article would be great! A video wouldn't be terrible either and you can see if it resonates with the audience based on analytics. Channels with 100k+ subs sometimes have a second channel with longer form content or related content. Looking forward to more vids!
@@machsuper nice to see you coming back. I agree with Rexus, the animations are nice and many people would enjoy have some special videos talking about them. Mainly because its something with a bigger audience.. In my case I got curious because I also plan on making a youtube channel. This maybe would help me somehow to enhance the content presentation and help on explanations. By the way, where are you from Australia? I've lived in Sydney for almost two years, but I'm from Brazil. One day I think of going to live in Australia again. Just not sure where. I enjoyed living in Sydney by the way. Great country, loved it!
Nice straight forward no mess overview!
Beautifully presented, mate! Top notch production
Scrapin' is wildly beautiful to watch, thanks for shooting and sharing this.
It’s a beautiful practice, isn’t it?
Thanks for watching Dustin.
Great video, great effects and wonderful info. Thanks!
Amazing detail! I finally understand scraping, thanks!
Nice keep up the good work. I enjoyed watching and learning from this video.
Nice to see some oldschool being done.
Great video, too btw!
Guys, a termendous amount of work and effort went into that, both from the effort scraping and documenting it - really appreciate that you've shared that knowledge and information - phenomenal job!
Subscription worthy!
Cheers Sharkbait! It was a lot of work, but I loved doing it all.
I most likely got this recommended from my history with machining videos but your VFX and aesthetic is stunning, and right up my alley. Beautiful stuff- I've seen proper televised documentaries with worse VFX.
Never enough scraping videos! I noticed also that the pin you used on the dovetail is the proper diameter that has it sitting in the middle of the tail. Ie, using a too small or too big pin moves the area of importance. Are you hoping to use this knowledge for a classic rebuild of an older mill? Seems like a lot of work in respect to the capabilities of small mills. I know, I keep bumping into size limitations all the time. Thanks for taking the time! 10 Months! A good reminder that nice things take time and a good job is not about how long it takes, but how well it turned out.
Yeah well spotted. I think Marcus told me that you would want to use a couple of different sizes to check more area of the dovetail to make sure everything is good. But there's something else that I didn't mention but should add to the article. On the side with the gib, where you dramatically relieve that inner strip, you need to be careful that the pin isn't reading off of that rough scraped area.
the animations are super helpful and well done.
Superbly done.
Wow! This is incredibly helpful!
I've always just assumed scraping isn't something I could do but given some time and a few practice runs I feel like this is something I could achieve, if much slower than a professional.
I can't have scripted a better comment for this video! I'm glad it was helpful mate!
There is a very good chance I have autism.
Trains. Hand scrapped parts on trains.
Enough said.
@@IAintScaredOfNoGhostminiature trains?
I’ve watched a whole LOT of your vids. I’m pretty sure you just need to ease off the Yerba 😂 That being said, I think I might also be a little autistic
Yippee
Nothing to be ashamed of or embarrassed about.
Broooo NEVER GIVE UP... I Love your Content
such a great presentation and explanation! thank you very much!
Thank you mate, I appreciate the nice words. ☺️
Hell yeah the 🐐 is back
Well done!
The ancient council of scrapers will be irate at their wizard secrets being divulged.
That’s why the industry is dying, they’re too secretive.
My God I've watched this whole video and found it thrilling. I don't even have a mill. I'm fact I don't even have Any machine tools. I think I need to go get tested for autism like Mr Marcus said to
What a comment! Thanks man! Glad you enjoyed it.
Super quality production and narration! When I've seen tables like that being machined in China, they've typically had 16-24 (or more) lined up to be ground at once. Your center-right high spot might come from one of the huge grinder's own webbed table supports running directly below that part of your table.
Cheers Mike. Very interesting suggestion on the webbing. I’d be curious to compare other tables.
Awesome!
Great video Christian
I just rewatched your video on bump scraping, I’d forgotten you scraped the swivel on your cylindrical grinder to 40PPI always gives me a chuckle
Thanks mate. You’d hope it’s decent after over 10 months of work.
love this video..
another key point for why 2 flat surfaces being bolted together need to be flat; it may seem flat and square to the naked eye when in reality it's sitting on 3 or 4 high spots. So you tighten and commision your machine, and after some use and vibration, those high spots disappear introducing backlash and error
great video / channel btw!
A pretty cool video - that Marcus guy looks like he needs a blood transfusion or a LOT less coffee !
👍👍 👍
killer as always ! best animations ever
also i'm pretty sure i do
Cheers Jake! Everyone in this industry either has it, or they suspect they have it. 😆
🤣 outro commect 😂 then i must have autism at highest level.. staying till the end and waiting for more to come at a black screen 🤪
Really good fusion of animation and real imagery to portray what may be new concepts for many...well executed guys! I also like the balance in messaging between what you experience as you learn with what is the best/right way to evolve to. You approach your learning with humility which is absent in many hobby "expert" videos. Just starting my own learning curve, navigating a path through the tooling and aids required could be a useful topic, though delivery in an interesting way...that may become the greater challenge. So many options, but a limit of funds for rarely used items may be a barrier for many, so what are the tradeoffs as you are getting started.
Thanks Kent! I spend a lot of time starring at the project and the video, philosophising about what's important and what it needs. I'm still not happy with the sequencing of it all, but the video had to get finished somehow.
When you say tooling and aids, do you mean for scraping or machining in general?
@@machsuper relating to scraping in particular. Scrapers, stones, straight edges, surface plates, ink rollers, laps etc.
When you do the hinge test (what you call the "pivot" test), the hinge/pivot points should be roughly 22% away from the ends. These are the Bessel/Airy points. If your part prints blue along the whole surface, and hinges at those points, you can be reasonably sure that it is flat.
Fantastic explanation! Subscribed!
Very worthwhile info and simply great presentation of contemporary scraping ideas. I keep hoping to see someone else who has discovered that scraping has devolved from the original methods and goals in ~1820's(Whitworth@Maudslay) to what it is now. Back then the goal was surfaces so flat and smooth that they wring like gauge blocks and that was achieved. Back then "points" were a by product of the process, not the goal for non bearing surfaces.
would be nice if you told us more about those methods
@@jonjon3829 I left the clues in my comment for those who REALLY want to know.A lot was written about it at the time. There is s short clip on my channel that shows a test result of that information. Since that clip was recorded I managed to get that disk to be better than a gauge block in flatness. Better than 1 millionth over 4 inches.
@@jonjon3829 Now I recall the correct name of the book "The WHITWORTH MEASURING MACHINE" downloadable from internet archive in several formats free. It details scraping methods and tools and much much more as it was originally done. It shows how Whitworth created the first accurate surface plates and parlayed that into several other important forms ending up with his Millionth measuring machine.
@@billshiff2060 thanks, I found a 1877 version, that it? I'm building a linear motor based machining center so any micron gained here and there is a bonus.
You’re right - this was quite useful and fun! Definitely earned a new subscriber. Autism might explain a lot 😮
Back in the day tables and slideways were usually done with a planer. Its very slow by todays standards, but probably as fast as grinding and has no tooling costs and makes flat surfaces with exceptional finishes. Youll notice planed tables by the stripes/lines in the finish
Why do you think they stopped doing it that way?
Let's GOOOOOOO
Great video and great visuals! Im confused why you stated it wasnt necessary to bring that back face into high perpendicularity with the table top though? It seems that this would be very necessary to insure the table is nice and flat to the finished machine. Also, I am super curious to see how you measure and account for perpendicularity throughout the machine. I have been thinking a lot about machine construction and this is an area I am confused about. Thanks
Using a reference Square you traverse the z axis to check for the table in relationship to the z axis and scrape the offsets according to alternative you scrape the column joint. Likewise you have to check that the x and Y axis are Square to each other otherwise your hole locations start to get very goofy. Lots to cover but Christian is incredibly busy dating my neighbor and helping her with her business
That’s THE Marcus ^
I hope that answers your question.
25:26 lol you're not wrong but I still feel called out xD
I felt the same when he said that XD
how do you do the "printing"? didn't seem to see that in the video.. Otherwise awesome vid!
You need a extremely flat reference surface, for a long but fairly narrow surface either a cast iron camel back or granite surface beam is used and for a shorter but much wider surface a granite or sometimes cast iron surface place is used. They're very expensive accessories though, considering how accurately flat they need to be (it's not uncommon for a 1000 mm camel back or surface beam to be flat to within 5 micrometers).
Awesome production value! Is there a reason to scrape the top of the bed? Seems like the ground surface is just fine because you'll probably be using a vice, which is locally as flat as you need. I understand scraping the bearing surfaces for flatness and allowing the bed to ride hydrodynamically on the way lube; it just feels extra to me.
I can think of a couple reasons.
Having a surface that’s out of spec for flatness is out of spec - it’s not good enough. I don’t actually know what the variation was, but it was probably greater than 20um. Still not huge in most applications, but a bad machine is a bad base for good work.
Also, without addressing that surface, you can’t be sure that it’s flat enough or that it’s stable. It might be convex and throw off readings of the flat ways.
Making sure its flat would give a better surface for all the future work you do with it, and you can have confidence in it.
Scraped my milling table as well. It had a twist of 0.2mm from one corner to another. I'm at dovetails now, one done one to go
Nice one! Are you experienced at scraping?
@@machsuper Some. I scraped a 6x18 surface grinder. In fact I rebuilt it, changed all the bearings except spindle which was ok. Bought it as scrap since the column was cracked. I welded it then scraped the 4-ways then scraped everything else. Removed the old paint to the metal and repainted. Replaced all the lubrication: tubing, metering valves, pump. Debating if to put servo and making it CNC. I do want to put a 0.1 micron glass scale on Z
I would think they would use a Blanchard grinder. The large rotating disk type. With a mag chuck on a carousel.
I don’t think I’ve ever seen a mill table with the circular grind marks of a blanchard. Mine had straight marks running the long axis. Not sure which would be better for the job, but I’ve been told they line up a bunch of them on the one big linear grinder and do them in one operation.
Great video. Cant doge the feeling that some talking head clips look color ungraded/too grey colors. Some more contrast and saturation would be nice.
I agree, I don’t know what I was thinking with some of the colour choices. I like the idea of a raw, high dynamic range look, but I didn’t pull it off well. I actually bought the camera hours before filming.
Really cool to see. Not a technique I've seen before.
But why not use the mill itself to mill the table to the cutter?
Almost all mills have a far larger work surface than their given travels to add to this tram error means even if you run a big enough fly cutter you’ll make a dogs breakfast of it. I’ve seen it done on a HM-52 and the results weren’t pretty. A metal shaper or surface grinder however is designed to plane/grind its work work table so you can do an awful job of the Cartesian relationships between axis and still get great parallelism/flatness of parts
Awesome! What software was that animation created in?
I watched all of your videos on this channel tonight. Awesome content. I subscribed and hope there is more to come.
And, if you every need advise regarding 3D modeling, feel free to reach out. It's what I do for a living, and I love teaching the skill to others.
Thank you so much Jon! I can’t believe I’ve made videos that would draw someone in for an hour or so!
What type of 3D modelling? Engineering brep or mesh modelling?
So the first step is to do the pivot test to eliminate any convexity by rocking the ends and get the imprint, then scrape it off?
You can go straight to the rocking and pivot tests. I think Marcus would do a single uniform pass of rough scraping just to break up the surface. I don’t really know if or why that does anything, but it kinda feels right, so I would do it too before doing the pivot/rocking tests.
Very cool animations, what software did you use to generate them?
Thanks mate. I use Blender for all 3D visuals.
It would be nice to know how the dovetail straightedge is used when scraping the dovetails, otherwise a very informative video! Thank you
It’s very much the same concept, you just have to be more diligent with the printing. You have to be careful to apply even pressure side-to-side so you don’t over print one side. The dovetail edge is just so you can get the printing surface into the acute angle.
Can you point me in the right direction for the 3D rendering? Looked really cool
G’day mate. I use Blender for all 3D animations. It’s a skill I’ve developed over the years. The more unique techniques used here were the shape keys to make high spots on the surface, and Geometry Nodes for the dimensional annotations.
Well done.
I know its not a hard one, but anyone have the model?
Well done.
Anyone have the model?
Make more videos 😅😅😅😅
Your videos are interesting
I’m trying, it’s hard to start a separate company at the same time. 🤦♂️
Any advice for how to increase PPI/coverage? I have a lot of trouble getting beyond 20-25 PPI and maybe 30-40% coverage (end goal is gage level accuracy, not machine way accuracy).
I think you would need to go to a very tight radius on the grind, like 90mm. Technique is important, I find Moore scraping a bit too hard to control well enough to hit the target often enough, which slows down progress. I forget what it's called, but there's a technique where you push straight like a normal roughing scrape, but scoop out to avoid burrs and can help to shorten the stroke. I suppose the important point is to narrow down the size of your scrape and gain greater control of the position of it so you only hit the peaks and nothing else. Hitting one peak divides it into multiple. This is just my thinking, but Marcus is the expert.
Thanks! Makes a lot of sense. I've been working on getting better at control over the position, but it's been surprisingly hard. Maybe a smaller radius will help with stroke length as well. @@machsuper
I would think they have bad to no stress relief process it's then machined flat, then slowly moves and twists out of flat.
Hi, good video! My question is , wouldn't it be better to use the table slots as a reference for the table blackface?
I can’t imagine a way in which they would be more useful than the back face. It would also be extremely hard to scrape; imagine trying to get a good print on one of the slot faces.
The back face is already ground and easily accessible.
@@machsuper I think that you are mistaken , because you looking at a machine in the way that a refurbisher do. The slots are not there , just to fit T nuts, And they supposed to be a reference to the axis machine for precise location,
Even the chanfer in the slots supposed to be precise ,they are used to locate parts as well ..
For actual machining scraping the side faces of T slot would be awesome but as a reference in scraping it wouldn’t be useful. I will do it one day on a toolroom mill just to shitpost about it
@@marcuschristensen5179 in no way I'm suggesting to scrape the slots, what I suggest is to use the slots or an unworn part of it as reference to the side scrapping , slots should be left to the standard size , being metric or imperial, unless they are completely worn out .
Most mills have the slots cut in gang fashion and are not incredibly accurate. Some machines have side wheeled slots but side wheeling with a horizontal grinder can result in drift due to spindle endplay/deflection. In an ideal work you would take a 11/16” T slot out to 18mm and a 5/8” out to 16mm. Peening from over tightening t nuts also really messes with the vertical faces so they’re rarely perfect anyway
Howd you do the animations?
Excellent video! an autistic guy from France :p
*_You didn't say or link the program you used to model this...._*
It’s blender he models fucking everything in it
Or you can just cut that shank of an old carbide endmill with an angle grinder instead of using gauge pins or those other fancy things.
Is it possible to scrape something if you dont have that giant surface plate?
Yeah Union Jack/planekation mapping for the top face and a dovetail straight edge for the slideways
@@marcuschristensen5179 Uhhh what?
Worth just taking a scraping class, Richard king if you’re in the US, Clive lamb if you’re in the UK and I’m in south east Queensland Australia.
@@marcuschristensen5179 Is it even worth doing, just looking at the tools needed to do the job you could buy already built machines. Scrapers are 1500$ and a 36" dovetail straight edge is 5500$...
A hand scraper is $110 new including insert. The biaxs brand new are about 6-7k AUD but I bought mine for $800USD and had it rewound. (You really do not need a Biax you can rough by hand just as fast or if working on the flat faster) A better option for a dovetail straight edge on the cheap is to cut out a section of a 1920’s dovetail lathe bed and if you have time but not the money you can scrape it without a surface plate you just need patience and a cheap Chinese precision level. Throwing money at the problem only speeds things up.
Hey mate, is there a reason that you aren't using metric?
That’s my fault I use tenths when scraping it’s all comparative measurements so Imperial vs metric is a non issue. I use 2 micron increment dial test indicator interchangeably with tenths. The one micron indicators are too jumpy for most scraping
G’day Filip, we used a mixture of the metric and inch. The reason for step scraping in 0.0005” is just because the indicator Marcus uses is in 0.0001” increments.
I thought I was coming down with a little case of autism, now I'm sure of it!...
Why scrape not surface mill?
Surface milling would require a machine that is within 5um to have any chance of matching scraping because the surface plate is within 5um. Milling also doesn’t leave a desirable surface for bearings, as explained in the video.
Позвольте кратко изложить, что отсутствует. Я вдоволь насмеялся: без роликов Хоффмана ничего не получится. Вы можете пропустить это видео, если у вас нет роликов Хоффмана, без них вы не добьетесь результата. Вам понадобится обычный подшипник с цилиндрическими телами качения - это секрет. При шлифовании металл подвергается резанию, вызывающему пластическую деформацию, часть металла отрывается от основной массы, а часть остается. Это влияет на точность из-за преодоления предела текучести и прочности.
Кроме того, учитывайте старение металла и температуру окружающей среды. Металл с различным содержанием углерода может деформироваться при температурных изменениях. Старение металла - важная тема: при шлифовке металл меняет свою геометрию из-за внутренних напряжений. Оставление металла на улице позволяет ему "успокоиться", после чего повторно снимают слой и дают снова устояться. Существует множество методов старения, которые стоит изучить. Работа со старыми станками легче, так как детали уже состарились. Также существуют квадратные шаблоны для оценки качества поверхности по количеству точек синей краски, а для тонкого снятия металла используют более мелкий скребок и метод соскабливания.
Let me briefly outline what is missing. I had a good laugh: without Hoffman's rollers, nothing will work. You can skip this video if you don't have Hoffman's rollers; without them, you won't achieve results. You will need a regular bearing with cylindrical rolling elements - that's the secret. During grinding, the metal undergoes cutting, causing plastic deformation, with some metal being torn from the main mass while some remains. This affects precision due to surpassing the yield and ultimate strengths.
Furthermore, consider metal aging and ambient temperature. Metal with different carbon content can deform with temperature changes. Metal aging is a crucial topic: after grinding, the metal changes its geometry due to internal stresses. Leaving the metal outside allows it to "settle," after which another layer is removed and the process is repeated. There are many aging methods worth exploring. Working with old machines is easier since the parts have already aged. Additionally, there are square templates to assess surface quality by the number of blue paint dots. For finer metal removal, a finer scraper and scraping technique are used.
This was a great video, but I absolutely hate this music - and it's so popular on youtube. The subtle continual pitch bending and the little yowl'y bits of voice really drive me insane
I don’t love the yowl’y bits either, but I quite like the rest of the song. I’d use music by Weird Inside if I could get the rights. I’ll remember your comment in the future.
OH DEAR - Let's Scrape for scrapings sake......?!
THE ONLY TIME TO SCRAPE ANY WAY/SLIDING SURFACE IS WHERE IT IS UNDER HEAVY LOAD.......
This is specifically WHY eg. MILL beds are not scraped but its knee ways and column are....
Scraping is DESIGNED to retain sub-decamicron amounts of way oil IN HYDROSTATIC COMPRESSION(pockets of oil under compression(like a ball SCREW in mechanical terms, for example). ....
The reason WHY MILL TABLE SURFACES AREN'T SCRAPED IS BECAUSE YOU WANT AS MUCH STATIC FRICTION(AKA GRIP) UPON ITS SURFACE UNLIKE A WAY(including it's front and rear sides) !
Sorry for being blunt, but human time and energy are precious, and when it's misguided through ignorance, then that's tragic..
BTW The referencing to "Chinese..machines." inferring cheapness, is because we're too cheap(economic means, geographical locale..) to be able to purchase new top quality equipment.
If one is on YT seeking knowledge in this field, then it's a given that we are amatuers, and have amatuer(hobby) machines.
Thank you China for giving MILLIONS of peeps worldwide the chance to learn and develop their skills(on amatuer machines) which we can improve as do our skills) which serve INCREDIBLY PRACTICAL AND SUSTAINABLE REASONS.
Rant over - Signed. A Machine Tool Fitter/Turner(Retired).
Не хотелось бы Вас разочаровывать ,но шабрите Вы еще очень посредственно
Haha that’s okay. It’s my first time on a cheap mill.
Autism brought me here.
This program brought to you by autism!
Way to much talk and teaching by somebody who can’t scrape , you know how I know because I learnt to scrape over many years. You played with it while your friend done the true work. Don’t teach others until you are competent yourself.
🥱 get a life dude
Wow, it took you THAT long?!
Hey my little So Boring buddy - it is ' way TOO much ' - how about you learn to correctly write English before making asinine comments !
🤣@@machsuper
Imagine talking shit on a video that teaches the sum of your life's work in only 26 minutes.😂
1. A “pro” would never get a hobby mill, let alone a trash one. 2. No one worth their labor rate would ever even consider scraping a mill table. It’s as if you just don’t understand...
Additionally, a pro doesn’t need to watch this video to get their work done. That’s why none are, it’s curious hobbyists, and professionals who like seeing what others are doing with machines that watch this video. It’s entertainment as much as it is education. Thanks for watching ☺️