# Resusitating Some Chinese Iron



## Baithog

Quite a few years ago I finally managed to save up enough to buy a little HF mill. I had no illusions about the quality I was getting. Getting was way better than not getting at all. The ways were warped so that several inches of travel wouldn't travel. I lived with it for years, being creative about work piece sizes. A year or so ago I hung stepper motors on the little mill to do CNC. That made made the problem unworkable. Years of using nothing but the center of the table had aggravated the original problem with wear. CNC meant that I couldn't selectively lock one axis or the other, or do gib adjustments on the fly. So the machine saw little use. The sale of some of my other toys and a deal with my wife got me a larger mill/drill. I considered converting it to CNC, but I like the feel of manual control. It did occur to me that the mill/drill was just large enough to re-machine the X2's ways.

Two weeks ago I got up the nerve to mill the X-axis table and saddle. Not being very patient, I assembled the table and saddle with the old gib. It slide smoothly from end to end with no wobble. I was very pleased with myself, but all was not well. Wear marks from the first slides showed that I had very little bearing surface. If I don't do something to smooth the ways, I will quickly be back to where I started. I have spent hours reading rancorous discussions on the net about the merits of lapping versus scraping.

Enough of boring you with background. I think I want to scrape the ways, and I think that I have a plan. Assuming that I can teach myself to scrape, this is it.


Machine a cast iron dovetail master.
Scrape in the master.
Use the master to scrape in the bearing flats
Use the master to scrape in the table dovetail ( or should it be the saddle first?).
Scrape the saddle to the table.
I plan to scrape in a block plane and a angle iron for practice. Does the above plan sound way too ambitious for a novice scrapist?

Saddle


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## Baithog

Saddle


Table


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## Ulma Doctor

ambition is the key to success my friend.
practice will assure your outcome.

do this any way you wish, but i might suggest...

if you have, or can get a surface plate of desired accuracy,
you can scrape each flat surface from the surface plate's reference.
then use the dovetail master you scraped from the surface plate to master the dovetails.
it may save you some time.


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## timvercoe

Gotta start somewhere...........Sounds like you have a good grasp on you plan and results.....   a china man mill sounds like a worthy place to start.  

Tim


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## gi_984

Second a surface plate.  You are dealing with small mill parts and it is easy to roll out some bluing on the surface plate and spot the parts.  Still have a tube each of the yellow and blue that "he who shall not be named here"  gave me at the scraping class.  I should of taken some pictures of my last scraping job to illustrate here.  But you should find some videos on You Tube.


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## astjp2

Gawd scraping is tedius, I have about 18 hours in both hand and powered scraping on my lathe saddle and cross feed.  I am only about 1/4 of the way done.  I was getting frustrated so I started to do 2 different pieces just so I could feel like I was making progress between the two.  I have someone locally who has given me some pointers on scraping but I am still learning.  I now have to make a new gib for the cross feed and eventually the compound rest.  Here is some of what I have so far....Tim


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## Uglydog

Yes, scraping can be tedious.
However, it fun for me to watch and understand that observing a real machine tool rebuilder scrape is efficient and quick. Seems job that takes me several hours takes them 20minutes. 
And their results are better!!
Practice....

Daryl
MN


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## Baithog

I am working my way through "Machine Tool Reconditioning". The description of how to sharpen  the scraper has me confused as to what I'm trying to achieve. I sacrificed a very worn Nicholson 
file and was not able to get it to cut cast iron. It would help to have a properly sharpened scraper to examine and try out, So I guess I have to get off the pot and order a real scraper. I am tempted to get an 18" tubular handle with a HSS blade. I can hone HSS as I have hard arkansas stones and  razor hones for my plane irons. That way I can start experimenting with the angle plate. On the other hand I will probably have to get a carbide blade eventually and build a lapper. 

I found some descriptions of home built lapping setups. They are based on available motors. Most of the descriptions use a cast iron face wheel. There was at least one mention of using aluminum or brass for the wheel. I have 5" aluminum stock. Would embedding diamond past into aluminum really work? 

Is 9micron the right paste, or should I go down to 7micron?


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## Ulma Doctor

to make a scraper from a file, you'll want the edge to be at about 3*negative rake
or you can make a sharpener like i made...


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## Uglydog

Dennis Danich mentioned:
"I suggest this link to buy a tubular scraper http://www.andersonscraper.com/Anderson-Hand-Scrapers.php" 

Daryl
MN


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## Baithog

I am back to the project now that the Christmas decorations are back in storage. I have a 9X12, B-grade granite plate. I would gotten a bigger one with a ledge if I had known I was going to go this route. I ordered an Anderson Tubular, 18" scraper with a HSS blade, tubes of Canode red and blue spotting ink, a 2" brayer, and a better indicator holder. I am bidding on a Tesa Tast indicator with a resolution of 0.00005" and a +/-.004 range to compliment my 5 tents resolution indicator. I probably won't win it, but I'll keep looking a a 1 tenth indicator. I know that I will be converting to carbide eventually, so I'm also looking for a used motor to spin a diamond wheel. I should have enough toys to start butchering and angle plate later next week.

I decided to take some rough measurements of the X slide bearing surface, just to see how nasty my machining was. The X dovetails and bearing surface were machined with the table top as the reference surface. I used both my 5 tenth test indicator and my depth micrometer to measure the left, center, right height of both bearing surfaces. Both instruments agreed, which was satisfying in itself. The measurements are in the photo attached. The bearing surfaces are slightly concave, which I suspect are easier for a novice to deal with.


.2155, .2150, .2165 top
.2160, .2145, .2165 bottom


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## 4GSR

You are going to need a longer surface plate for scraping the slide to, unless you you have a camel back type of straight edge to use. Those numbers are not too bad, I usually find the numbers to vary as much as .030" and more on slides I've worked on in my past.  If I got a worn out slide back to within .0015-.002" at any place measured, I called it good as long as the way members were flat to a surface plate or straight edge.

Start out heavy scraping the ends to about 3" in on each end.  Take impressions, and probably add on another 2"-3" to scrape.  By then, you should start getting marks from end to end, not many, but a few.  That will at least let you know where you stand on scraping.
Ken


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## chevydyl

Before I got my connelly book, I was able to sharpen my file to cut iron, ground the breast on the bench grinder, and ground the teeth off the back side, laid it on the surface grinder to make the ground off teeth area flat, then honed that to a slight reflection on my fine diamond knife sharpener, then began working the breast on the same sharpener, here's a tip, use a sharpie to color the breast so you can see that your actually honing the cutting edge, also drag the cutting edge on your thumbnail, if it will flake your nail, it should push cut iron, at least mine did, it even cut steel for a couple strokes before needing  refreshed lol. I'll take some pictures here after a bit to help you out


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## chevydyl

Ulma, Richard king suggests spinning that motor to like 1500rpm, and also tilt the table down towards the wheel to avoid chipping the blade. Those were tips I read about from the master


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## chevydyl

here are the pictures and how my blade is sharpened, when honing the blade I would rotate it on the breast parallel with the radius, rather than how it says in the connely book, but also in the book it says to have a flat edge in the part I read, maybe I skipped a part because I listened to what RK said about radius size pertinent to what type of scrape your after, large radius for roughing and small radius for pin pointing. this radius is in the middle of the road I believe. first time ive made one, I just wanted to try it out before my sandvik scraper and blades arrive.


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## 4GSR

chevydyl said:


> Ulma, Richard king suggests spinning that motor to like 1500rpm, and also tilt the table down towards the wheel to avoid chipping the blade. Those were tips I read about from the master



Richard King said that 1500 RPM is too fast.  You need to get the RPM down around 250-350 RPM.  You're lapping the edge of the carbide with a diamond lap of about 600 grit.  1500 RPM will burn the edge to where it will not cut properly.   Don't get me wrong here, you can make it work, but I've been in Richard's present and heard him say you need a diamond disk running at a lower RPM than standard motor RPM.  The Glendo he carries around to his classes only turns around 250-350 RPM.  I have an older model of one that looks like the Glendo and it turns around 250 RPM.  Originally used to put an honed edge on carbide turning tools.  Worked quite well on my scraping tools, too.


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## chevydyl

Maybe it was a typo then, cause it said 1500


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## Ulma Doctor

chevydyl said:


> Ulma, Richard king suggests spinning that motor to like 1500rpm, and also tilt the table down towards the wheel to avoid chipping the blade. Those were tips I read about from the master




I took RK's class too, here in CA

i patterned my sharpener off a glendo sharpener.
Glendo sharpeners operate at slow speeds


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## chevydyl

The speed thing must have been a typo then, but for sure it's recommended to tilt the table down towards the wheel to avoid micro chipping the carbide cutting edge


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## Ulma Doctor

my motor is tipped to 3*, the table is flat.
the effect is the same, regardless of whether the table or the grinding stone is pitched.
the glendo sharpener had a perpendicular wheel and a tilting table
i have a perpendicular table and a tilting wheel, the effect is the very same 3* rake.
there are many ways of accomplishing the same thing regardless of professional opinion.


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## 4GSR

I'm not going to argue over 3 deg.  I've always set mine for 5 deg tilt in to the grinding wheel.  Of course, back in the day, the  only thing I available was some worn out 6" OD diamond grinding wheels that were worn down to the aluminum in places.  And I hand ground the radius tilting the hand scraper as needed to get the negative angle needed on the face of the carbide.  Scraped a tone of cast iron that way. When I got a T & C grinder, used the same wheel, but had the all angle vise set up to the angle needed.

Boy, we are getting off topic here... IT's all good!!!


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## chevydyl

How far out of whack is my relief angle, I just off hand ground the thing to what a picture looked like, what I have found is all the masters talk about how to do it but never actually show good pictures of the blades up close, in a way that's easy for the super noob to understand what is going on. My blade cuts but I ruined the temper grinding the radius


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## chevydyl

Really hard to tell that the wheel is tipped, thanks for pointing that out


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## Ulma Doctor

something i tried when i was using a file for a scraper, i'd make the file radius on the end and no relief to the cutting edge.
it cut much better than a relieved blade, but it does need to be resharpened frequently.
it was a little harder to push, but it could remove a lot of metal in a single pass.


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## Baithog

I'm really enjoying the conversation on sharpening. I have been replacing carpet with a new hard surface floor in one of the bedrooms. I received a brayer, red and blue canode ink, and an Anderson hollow scraper handle with a HSS blade while I was otherwise occupied. I will eventually get a carbide blade, but I need to build my diamond hone first. Is 150rpm too slow? 

I need to get the HSS blade profiled and sharpened so I can scrape something. I've seen that 600 grit diamond is fine for carbide, but what grit do I need for final pass on HSS?


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## 4GSR

Don't use diamond on HSS, that is meant to sharpen carbide.  They sell CBN wheels for HSS that are specifically for HSS.  And 150 RPM is about where you want to be, 350 RPM max.  The Glendo units run at about 250 RPM, about a 7:1 ratio with a 1725 RPM motor.  My old Lenard Grind O Lap runs at about 200 RPM.


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## Joe in Oz

Using diamond on HSS (or any steel) is OK if the process has a low surface speed. Diamond dissolves in HOT steel but cuts COLD steel perfectly well. WHen I say 'hot' I mean as in 'sparks'. If there are no sparks its not going to disolve the diamond.

By the way, scraping with HSS or a file is VERY tedius. You spend 1/4 of your time sharpening or fighting with a blunt edge. Go straight to a fine grained carbide and sharpen every 2-4 hours scraping....


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## Baithog

I am well aware of the reputation of HSS for being tedious, but then scraping is tedious. I'm not sure that I have the personality of patience to scrape. I could get by lapping off the machining peaks, or even putting the mill back together 'as machined' and have it work. That is essentially what Seig did when they manufactured it. So, if after some practice pieces, it turns out I'm just way too bored to deal with a scraping project, then I won't have wasted my money setting up to scrape with carbide. I am cheap enough that I would kick myself for not getting that co-ax gauge I've been wanting instead. On the other hand, if scraping is cool, I can set up for carbide and relegate my HSS blade to softer metals. Aluminum bronze gibs come to mind.

My suspicions about diamond wheels was that there would be little migration of carbon at low speed, especially with some coolant. Iron has some interesting phase changes as temperature goes up, so figuring solid solubility and doping levels for carbon into iron is way more than I want to deal with. We had books of diffusion graphs back when I still worked in a silicon foundry, so we didn't even go through the pain of calculation then. 

I started sharpening my scraper last night. Connelly talks about polishing off the pits on the side of the blade. I didn't understand where the pits came from until I looked at the commercial HSS blade. It looks like it was sand cast. My previous experience with HSS tools were with ground ones. I would have been happy to pay another dollar or two to have gotten a ground blade. I don't have a course bench stone, so I had to order one. Polishing the flats on my Arkansas stones is painful. I am still wondering how fine a grit I need for honing the HSS cutting edge.


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## Baithog

I got my course/fine india stone yesterday and spent an hour or so working on the flats of the blade. They aren't as nice as I would like, but the pitting is off the cutting edge. A surface grinder would be nice for times like this, so I'll add it to the 'some day' list. I put a 3" radius on the blade and honed a secondary bevel at about 5 degrees. It cuts fingernails. It even cuts cast iron.

So I couldn't resist trying it out. I cleaned up everything on the bench and sqeezed a drop out of the blue canode. Except that the nozzle was clogged. After cleaning a quarter oz of ink off the plate, I was able to spread a thin layer and ink up the block plane. I forgot to take a picture of the first impression, so this is the second.


I'm having trouble controlling the blade, and it is hard to tell just where it is going to cut. I think that a smaller radius would work better, but maybe I just need way more practice. I forgot to stone between impressions for the first few goes. Things started improving when I remembered. This is where I stopped for the night. Contact is growing.


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## chevydyl

I'm hooked on scraping now, it does appear that your cutting edge is not good, looks like it is scratching in a few spots, over in the potd I posted a pic of an initial rough scrape, insane how much better the sandvik carbide blanks are over the file I sharpened, although the radius is huge on them, they need to be shaped. I'll be following you progress.
I seen someone put a mark on the cutting edge so they could have better sight of where it's going to cut.
Maybe you said already but what kind of scraper handle are you using? My sandvik is pretty stiff, I may thin it out so it has a little flex to it.


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## chevydyl

Baithog, I'm feeling generous, if you'd like, pm me with info and I'll send you one of my sandvik carbide blanks


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## Baithog

That is pretty darned generous, but I have an Anderson tube handle. Like you, I am finding it addictive. It's hard to find a stopping place. The real question is whether I will still find it addictive after a few weeks. 

The scraper does cut, unlike my file attempt. I am not overly happy with the quality of the edge, but that will improve with more time at the bench stone. I also need to pay better attention to keeping the blade parallel to the part. Allowing the scraper to rotate causes it to cut away from the center of the blade. I am going to steal some time later this morning to turn the wheel adapter for my slow speed motor. I need a way to sharpen carbide anyway. Right now it is time to shut down. The weather radio is complaining that we have severe T-storms on the way. Glad we won't get the snow storm, but the rash of tornadoes this year is aggravating.


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## chevydyl

Your blue is way way brighter than mine, I had to figure out a quick in town method to show contrast that I thought I'd share, I bought a tube of pale yellow oil paint from the fine art section, and a small tub of Vaseline, equal parts mixed thoroughly, spread it on the part and rub it in and rub it pretty much all the way off just short of using spirits to actually clean it off, do your rub. Not to hijack but here's the result.
I'm using permatex Prussian blue, really thin on the plate, and my work piece was surface ground prior to scraping so it's already flat, even with the current bearing the part is stuck to the plate.


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## Ulma Doctor

Hi Larry,
it feels good to scrape!
before they used diamond to sharpen carbide, green grinding wheels were used.
i have a green grinding wheel on one side of my bench grinder, it was a generous gift to me from member middle.road.
it's 100 grit and works very well for rough sharpening or putting radii onto scraper blades .
the sandvik blades don't have much of a radius on them, so i use the green wheel to reduce the radius, then rough sharpen.
i'll then further sharpen on the home brew diamond sharpener to satisfaction.
the green wheel does shed some grit- be prepared, but if you don't lean too hard you can get a lot of life from a greenie


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## chevydyl

I just bought a 120gr norton gemini green, but haven't been able to use it just yet, how long does it take for the actual sharpening after you have roughed it out on the green, is it minutes or is it dedication lol, I bought a 500gr and 1200gr diamond lapping disks for my finish sharpening, just curious as to what to expect, a few swipes and it ready to go or what


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## Baithog

I'll have to agree that my sharpening leaves something to be desired. The blade cuts but not very well. I will have to take out some time to mess with sharpening. I had wanted to avoid making a jig for the HSS blade to get the angles clean, but I may have to.

Chevydyl, thanks for the background formula. I am using canode for spotting, which is water soluble. I'm not sure it would like laying on a vaseline. A youtube video mentions applying an orange background before spotting. He took it from what looked like a past wax style can, but I haven't been able to find it for sale.

This is where I left off last night.


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## Ulma Doctor

looking good Larry!
keep at it you'll start to see more contact on the nose and heel.
they are usually relieved a bit on the ends for ease of use.


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## Ulma Doctor

chevydyl said:


> I just bought a 120gr norton gemini green, but haven't been able to use it just yet, how long does it take for the actual sharpening after you have roughed it out on the green, is it minutes or is it dedication lol, I bought a 500gr and 1200gr diamond lapping disks for my finish sharpening, just curious as to what to expect, a few swipes and it ready to go or what



Hey chevydvl,
actual sharpening after roughing for me is on the order of minutes.
i stop at 600 grit, others may go much finer- but i think the real advantage stops any finer than 600.
not to discourage, run what you have and be your own judge.
once you have secured the relief angle, sharpening can be very simple.


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## chevydyl

That's looking good man. 

Canode is water soluble,  but it's made with vegetable oil or some other thing (es dyjack told me this) he said it would have no problem playing with the permatex, although I ordered a sample tub of titanium dioxide since he was worried about air mail shipping the canode through the post office. (Powder vs liquid) I dont think mixing them would be an issue, and when I say rub off I mean I literally rubbed the yellow paint pretty well all the way off and what is left behind is more of a tint rather than a film or layer, your blue looks really good compared to the permatex, it's super thin on my plate so I wasn't getting false readings, plus being the part is already precision flat if I used a thicker film I'd never get the part unstuck from the plate lol, but after the rub I'm having to turn my head all around sidewards to even see the blue tint.


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## Baithog

You might want to check with artco [ http://www.artcotools.com/die-spotting-ink.html ]. They usually ship UPS or Fedex, but sent mine flat rate because it was cheaper . They even refunded part of my shipping. Flat rate to Alaska is supposed to be the same as down here. Just for jollies I looked up the Canode MSDS. The blue is Phthalocyanine blue pigment, Titanium oxide pigment, and Polyoxyethylene Sorbotan Mono Oleate emulsifier (Polysorbate 80). You have probably seen polysorbate on food package ingredient lists. It is available on ebay and probably locally from a soap making materials store. So if you get bored waiting for the sun to come up, you could get some polysorbate and mix your own water soluble inks. I really like the water cleanup, having had my spill incident.


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## chevydyl

I actually prefer to ship usps cause ups is insane expensive, I shipped a granite surface plate flat rate from standridge, only problem with usps is the weight limit and box size.
I'll have to check with the post office about shipping the ink if they are gonna make a stink about it.


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## 4GSR

chevydyl said:


> .............I'll have to check with the post office about shipping the ink if they are gonna make a stink about it.



Just take a copy of the MSDS sheet with you when go to the PO.  The stuff is not flammable or chemically react with anything it could come in contact with. Should be good to go!   The PO may put a label on the box if it contains liquids.


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## chevydyl

Thanks for the tip ken, but it was the seller not me that was concerned about it, but maybe know tell next go round I'll try and talk him into it.


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## 4GSR

Oh, just though of something else, I have received liquids in the mail. They were package inside a heavy plastic ziplock bag, placed in a box with shredded paper.  Don't recall a label on the box indicating liquids inside.


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## Baithog

I'm going to call this good enough and transfer my time to getting set up for carbide.


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## chevydyl

Very nice bro, that looks killer
I got some 8" lapping wheels on ebay from Kent supplies, they are 15 bucks each, I got a 500gr and 1200gr, and not having a machine I just gripped them in the lathe and free hand lapped em resting the scraper on the compound rest, it's working ok but I wanna build a lapping machine, and build a special tool rest that I can transfer between the grinder and the lapper easily. I got a 6" norton green wheel, I got it locally and it was kind of expensive, 37 dollars with a company discount. It's a 120gr, kind of a chore to shape the radius with that. With the 1200gr lap I was expecting a shiny edge but it's not, but it does cut like a motha lol. 

One question I have about your planer, now that it's super flat, is the base parallel with the blade? Is there anyway you can test for that? Does it even matter that much? I would assume it's the same effect as a mill head being out of tram.


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## chevydyl

Can you show a pic of your finish blade, I'm interested in the radius


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## Baithog

I used a 3" radius. I intend to drop that to 2" when I get my carbide blade. You can see some deep scratches in the sole of the plane. Those were caused by insufficient relief of the corners of the blade. I am still not happy with my sharpening. I don't think my depth of cut is more than just scratching at the surface and that is probably from not maintaining angles when honing. I should have built a jig, but I was impatient to try scraping. That is one reason I'm not sure I'm cut out to do scraping. Patience is not my strong suit.


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## chevydyl

Right right, I noticed my stuff being scratched up bad when I didn't get the edge perfect, the little chips in the edge would leave ridges. You could get a couple of them disks like I got, made it real easy to lap on the lathe, free shipping and only 15 dollars each. I still intend to make a blade holder for sharpening that slides and pivots. Interested in what you come up with.


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## Ulma Doctor

looks like you're getting  the hang of it!
something that may help your scraping, scrape at 45* angle to the centerline of the part you are scraping.
i noticed that you have some scrapes that are going transverse across the face, no big deal.
your scrapes will look more unifom if you go at 45* and rotate the part after each cycle

believe me when i say that patience is something that is cultivated, 
unless that is, you were given patience by the Gods.


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## Baithog

chevydyl said:


> Very nice bro, that looks killer
> One question I have about your planer, now that it's super flat, is the base parallel with the blade? Is there anyway you can test for that? Does it even matter that much? I would assume it's the same effect as a mill head being out of tram.



The plane is a Craftsman version of the Stanley 9 1/2.The blade can be shifted so that it is parallel with the sole. I use the plane to form triangles of bamboo to make split bamboo fly rods. The bamboo is planed in a steel form. The iron is set so that it will shave steel dust across the full width of the form.


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## chevydyl

I c, got any pics you can share of all that?


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## Baithog

I've been practicing while waiting for tools and material. The plane is scraped flat, as well as my small angle plate. I'm actually starting to get the idea. A stick of cast iron arrives next week to act as a straight edge. I should be ready to tackle dovetails by the time I get done with it.

I came to the realization that I really need to start working from the bottom up on the little mill, so I took the rest of the mill apart and cleaned up the base. I put it on my newly acquired 12X18 granite plate. The right rear mounting tab went clunk when I pressed on it. The base needed to be trued up in order to mill the extended base dovetail. It turned out that the base was twisted and humped along the Y axis, with the center being high. The whole base was milled flat at the factory, so sometime later it moved a lot. Since the mill ha never moved smoothly, it probably left the factory warped. Using the ground surface at the top of the base dovetail against my other mill's table, I took .116 off the bottom of the base before the cutter touched everything. I will scrape the new machining tomorrow so it is dead flat.


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## chevydyl

How are you checking the alignment of the dovetails, and how are you checking the geometry of the dovetails? I would be especially concerned on the perpendicularity of those DTs to the other axis DTs


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## Baithog

At this point I'm not checking anything with the dovetails beyond some rough looking at how bad they are. I am still at the beginning. First step is to figure out how to scrape. I am getting there with that. I am currently still collecting tooling - step 2. I thought that all I still needed was a straight edge, but my DTI to a dive to the floor last night when the holder fell apart, just another Chinese manufacturing success.. I am going to follow tertiaryjim's lead and scrape in a piece of durabar for the straight edge. Sag appears to be tolerable. I am planning to stress relieve in my kitchen oven set to a clean cycle. The clean cycles get up to 900F. I've read whole bunches of conflicting ideas about stress relieving cast irons. Durabar recommends 800F to !000F for 1hr/inch @ 1000F. An oven on clean cycle for 4 hours should get mostly there. Stress relief after rough machining is recommended because machining injects stress into the part. I really should cycle the mill parts that I'm machining too... just realized that.

For metrology I'm going with my home made straight edge. I'll scrape in an angle gauge to match the cutter. The exact angle doesn't matter as long as the saddle is scraped to mate with the other dovetail. I am working on a jig similar to the one described by Connely in chapter 16 to go with my .0001 resolution dial indicator, a precision square, and probably more. I'm sure I'll find needs as I go along. I'm just trying to keep the single project tooling to a minimum.

I'm not too worried about perpendicularity of the X-Y dovetails. My other mill is certified at .0004/8". If I do my due diligence with the setup and don't bugger it up with misguided scraping, the perpendicularity will be fine.


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## Ulma Doctor

when i took Richard King's class,
stress relief was accomplished by hanging the piece by one corner, and firmly striking the piece with a soft hammer on the opposing end.
the molecules realign themselves ever so slightly and stress reduction is accomplished.


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## chevydyl

Sounds like a good plan. You did see the post I made about the camelback correct? It was in the other thread you made. I can hook you up with his number if you interested. I priced out some durabar scrap and it wasn't exactly cheap. Only thing is the guy only has 18" castings, but they are pretty dang nice.
I'm itchin to get started on my lathe compound cross slide scraping and alignment.


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## chevydyl

I just read about the clean cycle of the oven in another post, tried it last night on my small angle straightedge, we'll see how it works out. But thanks to who ever for that tip, I had tried just a 500 degree soak but it didn't do alot


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## Baithog

chevydyl said:


> I just read about the clean cycle of the oven in another post, tried it last night on my small angle straightedge, we'll see how it works out. But thanks to who ever for that tip, I had tried just a 500 degree soak but it didn't do alot


That would be me. The OP was about acceptable machining tolerances for dovetail ways. We sorta got off topic concerning straight edges. I would still like to know how the call out of the dimensions on the shop drawing from a machine maker or the specs the QC people use to certify the ways for manufacturing. You can get away with quite a bit, judging by what is being sold at the bottom end (see my next post). I made a lot of stuff before I got exasperated enough to rip the machine apart.


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## Baithog

I should be up with a sharpening system and carbide next week, but in the meantime I have been amusing myself with scraping the bottom of the base.


I flipped it over on the big plate and took some measurements to the top of the reference surface at the top of the dovetail. That surface was as flat as I could measure.I them measured to the flat bearing of the dovetail. It was less than .005, except over the shiny part. That was .oo1 higher than the rest of the bearing. Twisted, warped, and lumpy...


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## Baithog

I haven't fallen off the edge, or given up. I have my scraper with carbide blade. The sharpening system is functional. I even got a bigger granite plate. My efforts have been going into making the straight edge that I will need for fitting the dovetails. I got a hunk of Durabar and started carving. Visual inconsistencies showed up in the metal while machinin the bar true. That was thrashed about in http://www.hobby-machinist.com/thre...o-peel-off-of-virgin-metal.43907/#post-376831

The bar is squared up as much as my machinery is capable of. The angle that allows the straight edge to enter the dovetail is cut. I am now hogging out the lightening pockets. The photo shows the pockets already drilled. I should get an end mill holder today, so that I can proceed to the removal of the rest of the pocket. I have had persistent problems with the mill being sucked out of the collet when taking heavy cuts. I am hoping that the holder with its set screw will keep the depth from increasing. I expect to stress relieve and final machine the straight edge next week.


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## chevydyl

Nice man, I too have run into inconsistencies in the metal while machining, it's most apparent when surface grinding, it will skip over the surface with no sparks in some spots.


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## Baithog

So everything is roughed out, the pockets milled, and the straight edge has been stress relieved.


So on to the fun part, scraping. But first I needed to clean off enough space on the bench to do the scraping. One of the things cluttering up the bench is a Y-axis extension. Mini mills are notorious for not having enough Y travel to do anything useful, especially when the factory machining is so poor that you don't even get the advertised 4". Most extensions move the column back and extend the base dovetail to the rear. That used to work OK, but the later base casting have been thinned out in the rear. I had a nice chunk of 1 1/2X2 1018 steel that I could mount on the front. I installed dowel pins to keep the steel in one spot, then drilled and tapped for mounting bolts. I will put epoxy between the base and the extension before I re-machine the base dovetail. Pins, epoxy, and 8mm cap screws should keep the extension in place.


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## chevydyl

that's awesome man, good job, did you send it out for stress relief?


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## Baithog

I went the kitchen range route. I put it through 3 hours of oven clean. I'm thinking that I am real close to recommended temperature for durabar and soak time was close to 2 hours per inch of thickness. I'll hang it and ring it a few times then see what comes of the scraping. If it seems to be moving, I'll put 'er back in the oven for a few more hours. I'm not sure how much I'll get done right away, what with Easter and out of state company. Living in Florida pretty much guarantees that you'll get visitors around spring break time.


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## chevydyl

That's how I did mine, it worked for my small straghtedge, supposedly 932 degrees is what they can get to


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## Baithog

I finished the milling on the base last night. I wish that I had gotten cast iron for the extension, but that was decided a few months back when I was dumber. Now I need to mill the saddle. I was only going to do the X-axis when I started this project, so I have already milled the table and X side of the saddle. Now ai need to get the saddle on the mill so that the Y dovetail is milled at the correct angle. I am thinking that I'll clamp the mini mill table to the mill and align it to the mill's x travel. I'll then attach the saddle to the mini mill table and clamp it. That should make the saddle as accurate as my mill. I don't see another way to get the saddle on the table. Any suggestions?



And now I get to clean up all the cast iron dust!!


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## 4GSR

Baithog said:


> ....snip....
> 
> And now I get to clean up all the cast iron dust!!



Take all of that cast iron dust and small chips and add them to your fertilizer spreader and spread all over the yard.  Adds a boost of iron to the grass!

BTW- Nice job!


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## Baithog

I did some scraping on the base and saddle. I'm still not happy with the points per inch, but it is as flat as I can measure. I cut cast iron gib abd scraped its bearing surface. Put together, the Y-axis is not air bearing free and smooth as silk. It is smooth and it is an easy push by hand to get full length motion.

Next I need an actuator. I have the choice of acme screw. It would be a !/2-10 2 start with anti backlash nut. The other option is an imported class 7 ball screw. Both are in the 5 turns per inch range. The ball nut will take some creativity to get into the limited space, but should take less torque to turn it. The Acme nut is more compact and marginally cheaper, but sucks up torque with increased friction. I am leaning toward the ball screw mainly because I prefer to use motor torque to machine rather than being sucked up by the screw/nut. Any wisdom? I suppose that is more of a CNC forum question.


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## chevydyl

are you doing a cnc conversion? the only issue with the ball screw is you may have to use the gib locks when not using that axis to machine.
lookin good man


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## Baithog

The machine was doing Quick and Dirty CNC before I tore it apart. It will be going back into service as CNC. I have the motors, drivers, and software. I just didn't have a machine that worked very well. I didn't originally go whole hog in case it wasn't as useful as I thought it was.


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## chevydyl

I should elaborate on that, the cutting forces will actually pull the table or push it away because there is no friction on the ball screw, where as the acme thread form resists that because of its thread form. on my machine ive never noticed anything moving when manually machining but just for safety sake when im manual machining I lock the axis for heavier cuts. also with the ball screw you will be able to climb cut


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## Baithog

I put the Y-axis together last night and it didn't work. The saddle slide nicely right after the scraping, but once I got the ball screw installed, it started hanging up a little over halfway back. I took it all apart and just installed the saddle. Sure enough it no longer fit. So out came the scraper and I managed to get it to traverse. It's stiffer than I wanted, but it moves the full distance under hand power.

On to the X-axis for more scraping fun.


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## chevydyl

So, she settled out, you need to put those parts in the clean cycle oven for several hours like your straight edge, otherwise I'm afraid it's gonna move again


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## Baithog

I probably should have, but it's a little late now. I didn't expect it to keep moving. The traditional way to season a casting is to let it sit. Well, this mill base is almost 7 years old. Maybe the machining to relieve the base for the ball screw nut introduced the movement. Gotta love cheap asian tools.


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## Baithog

I finished fitting the X-axis today. Drilling the little divots in the gib was a pain. It is tight and slides decent. No post assembly fitting like the Y-axis. I'm pretty much done with scraping, so i will take up further modifications in the "CNC In the Home Shop"> "Machine Build Logs" section.


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