# Making a Cheepo Import machine...better...hopefully



## komatias

Hi all,

First off, thanks for the previous post on the topic of reconditioning and machine way scraping.

Last February, I bought what a thought was a good deal. A band new Chester Super Lux Mill/Drill with DRO, Stand and assorted accessories. The grand idea was to convert it to CNC. Previously I had converted my little Chester lathe to CNC so I was pretty confident I could do it. I also own a well used round column mil/drill that is actually pretty handy. I installed a cheep DRO with capacitive scales similar to the ones found on you digital vernier. 

The conversion of the new machine went pretty smoothly.

[video=youtube_share;fbEzZo76BDo]http://youtu.be/fbEzZo76BDo[/video]

So up until the beginning of the year the Chester Lux was working ok but for some reason the y axis was producing a lot of vibration even though I had plumbed in a single shot lubrication system. After faffing about with the electrics to ensure I was not losing motion somewhere, I took a closer look at the slide ways. What I thought was pretty hand scraping was ugly gouging. I guess the manufacturer did this improve lubrication....

Of course I would have been none the wiser had I not discovered scraping. First through Youtube then the various machining fora, that Richard, Forrest and McGyver post on.

So I decided to see what I could do about making this machine better by scraping it in. 

The plan of attack is:
1) Scrape the y axis ways that are on the base using the clearance surface as a datum and the left side way. The left side way does not take the tapered gib and was pretty flat and parallel to the datum to begin with. Master for this is a camelback straight edge I picked up used and have scraped flat pretty well.
1a) scrape the right hand side flat and parallel to the datum and hence the right hand flat.
2) Scrape the dovetails in parallel once I am happy with the bearing. Will need a prismatic flat or a straight edge with a long wedge for dovetail spotting. for this. Anybody in the UK selling?

3) Scrape X-Y saddle flat and parallel using my granite table as a master
4) Fit the saddle to the base to scrape in the gib

The rest of the machine will have to wait until I am happy with the above.



Before I started the scraping, I got a 24"x18" granite surface plate, from Rotagrip. A Sandvik scraper from Greenwood with a 25mm wide blade. Diamond hand laps, diamond abrasive wheels came off ebay. For spotting I started with Stuarts Micrometer Blue and Red, the latter was not easy to find. I bought 3 different brayers from a craft shop, 2 hard, 1 soft. Then I came across a 2ft long camelback.

The surface plate arrive bone dry so I squirted it first baby oil, let is wet for a couple of day cleaned it off and repeated with WD40 to condition it nicely. 

The scraper took me a while to figure out but I have found the various angles to use it at to get it to cut as wide, deep and more importantly the position I want to scrape. I use both hands on the shank and place the grip on my right shoulder. The hands guide, the shoulder pushes.

The spotting compounds were a waste of money. The red is too thin and barely visible when spread, can't even use it as a highlighting compound. The blue was OK but dried up too quickly and when thinned out was unworkable. Have settled for Dykem Hispot blue and will keep going with it since I can find any water soluble stuff here in the UK. Briefly tried water based poster paints but was not happy with how they spread. 

Decided to attack the camelback first. The base was rectangular and not very proud of the superstructure. This was rectified on the manual machine. A relief was milled on the superstructure to get and a chamfer on the base. Both now allow spotting all the way into the dovetail relief. Following the good advice from the various masters on the internet I have achieved the following:






Click to see the larger picture Used a stone to deburr as the file I rounded left too many streaks. The edges are darker because the flat surface actually wrung onto the plate with the hispot. Had to knock it off as I could not lift it. Pretty happy with it actually. The remaining spotting on the surface plate looks like this:




On a dry plate it rotates at around 2/3rds of the length away from the edge I am moving.

The base looks like this:





Notice that the flat clearance surface has an A stamped on. I guess this is to denote the datum the machine builder used too.

View of the original scrapejob...:




After a few cycles the flats looks like this:





Notice the gouged oil retention features?

Photos of the tools to follow, didnt want to use the phone with my blued paws

Once I get the surface to a good flat condition I will measure it up and correct it if need be.

A tip to anybody thinking of buying a small Chester machine...don't. There are other similar sized machines with better construction out there see the youtube comments for more info.

Regards to all and again thanks!


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## Richard King

To all who are new to retrofitting a machine you should understand that 99% of all CNC machine built today do not use iron on iron ways.  They use a Teflon product called Turcite or Rulon bonded to the short side of the ways or they are linar ball ways to let the machine feed very accurately and smoothly.  It eliminates "stick slip" or a jerking motion when it moved.  Stick slip is caused by lack of lubrication or does not have 100% area oil film.  Even scraping the ways as you have done will not cure stick slip or "Ringing" together.  Looking at your scraping it has way to much surface contact for cast on cast.  Plus you still have to much bluing on the ways and it looks smeared.  It looks pretty good, but to tweek it you need to measure how deep the scrape marks are or you low spots.  When you have deeper scrape marks it holds the thin film of bluing.  When you finish scraping the way, brush of the chips and run your fingers over the way and feel the burrs, then dry lightly stone the burrs off.  It appears your stoning to much and with solvent as this will cut off to much material and you will get to high of contact area.  50% contact is best for a iron on iron scraped way.  

Use a surface gage and .0001" indicator and set the gage on the flat way and your straight edge and measure from one high spot to the low spot, the measurements should average .0002" deep.  This will allow oil to stay in the low scrape marks to get the 100% film.  Be sure you have an oil groove in your shorted side to on a diagonal line to spread the oil from one side of the short way.  One shot lube is for cast on cast non CNC machines as it will give it a shot of oil and then shut off.  If you investigate lube systems on many CNC machines they are called continuious lube systems as it pumps oil all the time.  

The reason they use the Teflon with bronze slivers mixed in is so you can program your CNC to move 001" and not jerk.  On conventional machines you are taught that if you have to move .001" you move it backwards .025 to get the oil under the high spot and move back .026".
But as I said on the Telon it is self lubricating and you can move .001" in one shot.  The one shot lube systems also work on Teflon ways as it helps increase the life of the Teflon as I said it is self lubricating.     

As I have said in the past, You get what you pay for.  The 2 students who brought their Chinese made machines to the GA scraping seminar also learned how lousy they were scraped at the factory.  We re-scraped them in class.  I have seen a hand-full of those Chinese mini machines and they all had lousy scraping.  Its as if they fly cut the ways and scraped them a little smoother.  It looks like they had watched You-Tube and scraped the ways with a file and never had any formal training or read anything here  .  

That's why if you can find a old Bridgeport or American,  British or German build machine you are far ahead of the game, as they were scraped by a pro at the factory.  But as they say you have to love em or leave em...and with the influx of machines from China you have to learn to scrape them to rebuild your new machine way systems.      Rich


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## DMS

I scraped in the saddle and tailstock of my minilathe. It wasn't scraped originally so much as ground out with a rotary burr (or, that is what it looked like). There were 3 contact patches on the saddle, each about 3/8" in diameter, and the thing moved a lot under heavy cuts. Scraping made a HUGE improvement. Thanks for posting your experience komatias, and thanks for the tips Richard.

One thing I also noticed on the mini was that the CI was incredibly soft. I made a prism from durrabar sometime after, and the stuff was 10 times harder.


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## komatias

Thanks Richard and DMS!

I have been contemplating Turcite actually for the saddle and gibs but not sure what thickness to go for.

Now I have a bit of a predicament....

The flat ways shown in the above post are ok, not perfect but ok. The dove tail measured parallel to +/-0.015mm which is the resolution of my DTI. The spotting using the camelback is consistent. So I have left them as is for now.

So time to see what the fit of the saddle is like. First step was to "cut" the originally ground surface then cross the cuts.

Spotting the saddle on the surface plate gives this:




Again pretty uniform, bearing nearly everywhere. I measured the parallelism of the the two flat bearing sides of the saddle and the numbers are not great there are dips way into the 0.1-0.2mm range. Hoping to fix that on assembly. Remember  I am going ground up here.

So I spread the hispot on the base's flats and this is what I got:




The first one corresponds to left hand side flat shown above.

Clearly, the ways are not parallel to datum surface. The one dips toward the dove tail the other away from it like this:




Using a DTI on a surface gauge, I get a variation averaging 0.05mm from the inside of the dovetail to the outside. 

Question here is: Do I continue to scrape the saddle to fit the base, which would be the quickest way forward I guess, or do I try and level the base's ways and in the process make them co-planar. I have considered sending the whole thing to a machine grinders to get it fixed up but would like to at least try before I give up and go that way. (Still looking for a prism to spot the dovetails with)

Regards

George


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## Richard King

Next time you have the saddle on the surface plate check all 4 corners as they have to be parallel .  Be sure you hinge the saddle by holding end with both hands and by moving the end of one  to check the pivot points on the other end; should be 25 to 30 % from the outside edge.  then hold the other end and move it left and right about 3" to and fro. and again 35 to 30% from that end too.  It looks like it is high in the middle on the left side.  When it is high in the middle the saddle will pivot in the middle.  I teach there are 4 Rules of scraping. 1) individual scrape marks meaning you scrape a low spot and then you skip the same width and the scrape again scrape, no scrape, scrape or  0 0 0 0 ,  2) Individual scrape marks  

0 0 0 0 0 0 0
 0 0 0 0 0 0 0   There is individual scrape mark lines, so the scrape marks do not touch the scrape mark above it

3)  Depth of the scrape mark,  .0002 to .0004 deep scraping marks or pockets.   4)   HINGE or pivot to find the "rotation of points"  25 to 30 % from the ends.      After you scrape the saddle on the plate the use it to scrape the base.  When you ink up the base with the scraped saddle the measure the 4 corners again  It has to be the same on all 4 corners.  To all my students, remember when I say you unconsciously scrape the outside edge and not closer to the dovetail?  This is a good example of that.  

Not trying to pick on you Koma , but you have to consciously make yourself scrape the dovetail under side and it is a pain to scrape close and you bang in there.  I would measure the saddle and make it a alternative straight edge one time with it one tome with the straight-edge, etc until you get the 4 corners the same off the base ways.page 207 fig. 23.5 of the Connelly book.   The ways should be parallel  and same angle from edge to under dovetail so when you check the 4 corners with a surface, moving the gage from sde to side on the same spot the indicator will read the same.  

I hope that makes sense.  Oh after you get it scraped you could try it with out the turcite, and if you still get stick slip, you could use some .030 on a home shop machine.  If I was going to put it on a new production machine I would use .047".

We can talk more about that later.    You will always find me on this forum now as I am a Moderator and check it several times a day.

Rich


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## komatias

Richard, Thanks. 

When I was doing the long base ways, The camelback straight edge was not spotting all the way into the dovetail except on the left hand way. Did I wrongly conclude that the ways where out from the start? Maybe in my ignorance, I only scraped where I saw blue spots. 

The technique of scraping I follow can be tweeked for sure and I will make the effort to follow the parallel scrapes with gaps between them like you describe. Point taken on the deburring, of the ways too. For the straight edge I was fascinated on how the shine came up on the high spots when I was getting close to flat.

Coming to your point about the saddle, are you recommending the following process:
1)Scrape the saddle flat and parallel to itself on the surface plate.
2)Blue the saddle and use that to show me the contact areas on the base and scrape those in.
3)Use the camelback straightedge to ensure that the whole base flat is actually flat.

I can see the logic behind this. The saddle is shorter in length than the base so how do I go about spotting? Lay on a thick layer of blue on the short flat and slide the whole travel? 

Or do select a region of the base's ways ( the long ones), flatten that and then use the straight edge to bring the remaining areas to that reference? Like this below:




The ways will be parallel to the datum surface when top corners of the saddle are parallel to it, measured using a DTI on a surface gauge.

(Fingers crossed it isnt too bad on the dovetail sides.)

Tonight I will spend taking photos and rough measurements of the various parts so I can write an RFQ to send to a machine ways grinder just out of interest.


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## Richard King

First I want to say Thanks to GA Bill, he really "got it" on how to scrape ways.  As a teacher it really makes me happy seeing my students like Bill and Jim "Get  it"   They are struggling and it's like snapping their fingers when they finally understand it.  Thanks Bill and Jim for making me proud!  I also want to thank all my students.  

Back to UK Bill,  If I recall didn't you made a straight-edge out of a window weight and had a sore arm that was super painful when you started?  UK Bill was asking several of us experienced scrapers on another forum and I want to thank him asking the question here. 

I wish I knew how to draw with a program like that, pretty cool.   As I said before scraping back on the dovetail inside edge can be a real pain because it's hard to see back there; the scraper blade is to thick and cant get wayyyy back in there. Page 60 Connelly book fig 9-12  That is why many will cut a relief back there on a mill, shaper, the Connelly book shows a 3 side saw page 12 fig 4-1. Groove cutter (I have never had a lot of luck with one, but to make the point)  So its easy to create the unknown high spots back there that cause the straight-edge to hit hard on the outside edge making it look high out there and you accidentally scrape out there changing the original gemometry or angle.  

No You are correct thinking it was screwed up from the factory and you did nothing wrong, who knows ..but this is something that happens a lot when your learning how.  I can say you are not ignorant, that is an ugly term that I would never say.  It's a problem that happens to everyone, even me from time to time as my eyesight isn't as good as it once was.

We always teach to scrape the longer member first and then match fit  the shorter surface to it.  With that said I will scrape the saddle of all machines on a plate to keep the geometry or flatness so all 4 corners are the same height before-hand as it helps speed up the job.  And as I said I make it a master plate and use it with the straight-edge alternatively.  I believe I mentioned in the other thread about the super high spots get shinny like a mirror when they are super high.  Another thing I teach and GA Bill can comment on this, you not only look at the blue where it rubs off on the way your scraping, but you look at the straight-edge and saddle where the bluing rubs off.  The high spots will rub off more blue on the straight-edge where it is super high.   This is why I stress good lighting so you can see back in there to a void those high hidden spots so you don't miss them back there.  Another thing I do when scraping a dovetail, I grind a top corners of the blade thinner so it can get deeper in the V.   

There is a lot to remember when scraping, that is why I have the 4 rules and that is why I have the students repeat them so many times during the class.  So important.  1 )  Individual scrape marks 2)  Individual lines of scrape marks  3)  depth of the scrape mark  4)  Hinge the part.

One other way you can find that high edge back there is to set you angled straight-edge on the flat and slowly slide it back into the V or dove and feel for it to hit a ridge and jump in or lift up the straight-edge when it hits the burr high spots back there. Another thing to do is to rub it a lot of times (min of 6 times) to shine up the high-spots on the part and as I said a straight-edge.  One has to be sure there is no sharp burr back there too so you don't scratch your master.  I like to use a paint brush with the brisltes cut back to sweep out the chips, then a tapered slip stone (Norton MS-24) or a knife edge file to be sure the burr is gone.   Scraping a base, saddle and table is like building a house in some ways.  Number 1 you have to have a solid base or the foundations are level and parrallel, and as you build up you keep everything level and square (4 corners the same) and if you check as you build up everything will be good when your done.   UK Bill there is a learning curve, and your technique has improved 1000% from the beginning, you should be proud of your-self and work.  GA Bill had an advantage or UK Bill, I was standing behind him and telling him.  It is a rael pain to learn and teach I will add over the internet.   Rich


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## komatias

Richard, would you kindly post the link to the other forum? We don't have many advertising scraping hands in the UK so any exposure you can share will be appreciated.


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## Richard King

I can't find it as I delete my history on the other forums.  You sure sound like the guy I helped a few months back on the other web-site, he had a lousy chinese import, had scraping issues at first, etc..  I can not mention which one on here, I have been asked to not mention other forums by name.  I still contribute to them, as I find I can help in all 3.  This forum has rules and I like the idea that Nelson had when he created this one.  No foul language, no insults, no hassles allowed.  Just friendly info.

You can contact my friend David Iverson and ask him if he knows a retired scraper who might like to teach you to scrape in the UK.
http://www.wmtg.co.uk/


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## Richard King

GA Bill, As you remember I say in my DVD, "I don't care how you scrape as long as you can get the same results in the same amount of time".  I have used angle grinders with a cut off wheel to knock out that apex and high area, (I like that term, thanks) .  Bill I also say "you are limited by your imagination" and it sounds like you engineered or invented a method to help you and it worked.  As you know you need to be careful not to grind to deep and make a hole for swarf and chips to enter the way system.  I am so happy to see you doing so well after only 5 days of training, you stayed the 2 extra days right?   I wonder how everyone is doing.  I think I am going to email everyone and ask.  Had any luck making a power scraper?  I figure if you watch E-Bay and Craigslist you will find an old blue one for $300 to $500.00, hardly worth the effort to make one from scratch I would think, but use your imagination.   I am sending one of the CA class students a link to your idea on making the blade sharpener as soon as I finish this note.   Bill I am so proud of you and please keep teaching, as that is what I need you to do.  Thanks again and keep up the good work.  Rich


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## komatias

Well I have managed to find a biax,doesn't have many bits but ia a start. Richard did u ever ger the dvd in an porrable electonic format?


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## Richard King

Yes I did....email me and I'll sell you a link to it.  Richard@handscraping.com


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## komatias

Well in anticipation of the Biax turning up I thought I would give the parts another go using the manual method.

First off, Richard I gave the method you described in the previous post of:
0 0 0 0 0

 0 0 0 0 0

  0 0 0 0 0
some thought. I guess this way you do not end up digging a hole in the work, seem to remember you mentioned this about the Biax video on Youtube on another thread. So I gave it a try:




Any better?

I had also tried to see how out of parallel the saddle is to itself ( top x-axis ways to the bottom y-axis). Well I was getting a variation of up to 0.08mm. The needle of my DTI was BOUNCING....hardly surprising when I cut the surface lightly and spotted it:




After two passes this evolved:




The high streaks are from the super flat grinding wheels used...:lmao::rofl:

Anyway, an RFQ has also been sent out to a couple of way grinders in the UK to see if it really is worth the effort in the end.


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## Erik Brewster

It looks like you are going in the right direction. It also looks like you have the consecutive scrapes nearly overlapping, but the rows are space apart by one scrape length. You want the individual scrapes to be spaced apart by an equal amount in any direction. I find this much easier to do when I scrape 45 degrees from the long axis of the way, so I am moving perpendicular to the scraping stroke when moving to the new scrape location.


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## Richard King

Erik Brewster said:


> It looks like you are going in the right direction. It also looks like you have the consecutive scrapes nearly overlapping, but the rows are space apart by one scrape length. You want the individual scrapes to be spaced apart by an equal amount in any direction. I find this much easier to do when I scrape 45 degrees from the long axis of the way, so I am moving perpendicular to the scraping stroke when moving to the new scrape location.



Erik is correct the scrape marks should be spread out and not overlap when going gr a finish cut or 20 PPI.  The ways now look like your in the "rouging" stage  The rule f thumb is you rough scrape until you get 5 PPI per square inch over 100% of the part surface keeping in mind you want to finish with on average 20 PPI with 50% of each (per) square inch.  I tell guys when you rough it is like scraping off paint, so long 3/4 to 1" strokes that overlap, then shorten your stroke  as you get more PPI until your happy with the look.  Just imagine how it looked before you started, it is 1000% better now.  The one picture looks like the one way is high on the ends and the other side is high in the middle.  This is why when using the straight-edge you hinge it to find the rotation of points, some call them the airy points 25 to 30% from each side when finished.  Then your final couple of passes to relieve between those airy pints appox .0005" to .001" lower.  When your done at 20 PPI and 50 % POP the stroke length will be aprx. 3/16 to 1/4" long.


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## komatias

Hi all,

I found a working Biax in Germany and promptly parted with my beer tokens for it. It worked wonders, surprised at how effortless it is to use, even badly.




It has been painted white at some point in its life.

I can now get spots on the edges:lmao: Yes, I know I need to make sure I do not strip the phenolic gear

So I was working away at the saddle to get the two flats parallel and something inside went pop....bugger.... 

It seems that something electrical has happened. I have opened it up and seen that a repair has been done on the cables to the motor. One of them was loose and the other parted company with the power line pretty easily....bugger x 2. The brushes are still ok thankfully.

I can get the front end of easily and read on how to remove the wobbler. How doe one remover the motor though?

So the plan is to resolder the wires and give it a try. If the motor has given up the ghost then I may have to ghetto something together. 

Photos of the biaxing progress to follow.



Added later: False alarm! Biax is working fine, it was the safety fuse that blew. The fuse was a 3amp one. Installed a 10amp fuse and fixed the cables to the motor windings and am back in business!


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## Erik Brewster

A Biax sure makes life nicer. Don't forget to figure out some diamond sharpening system. Glendos work great. Here are two cheap substitutes:
http://www.hobby-machinist.com/showthread.php/14987-My-cheapo-Glendo-substitute

http://www.hobby-machinist.com/showthread.php/11032-Glendo-lapper-clone?highlight=glendo

You can sharpen by hand on a diamond stone, too - it's just more work and harder to hold the angles.


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## Richard King

In the old days when the biax was used to rough parts and then finish scrape by hand those blades were designed.  That insert holder is so stiff it will literally feel like your chipping weld or as I say in my classes feel like a jack hammer.  You need to buy or make a 150 series blade as  they flex and are forgiving and you can finish scrape using it .  Can rough to finish with one blade..  The style has changed the way people scrape.  I never recommend you use that blade unless your rough scraping a large scored casting that are scored.  For your little mill you need a 3/4 x 5" long flexible blade that has "feel".  Ground with 60 (r)  radius and a neg 5 deg on both sides.  I am now teaching a class in Oakland CA and 2 of the students have or should I say had those insert style holders as they came with the BIAX they bought on Ebay.  I let them use a 150 series blade and the Paul said  "You were right the other blade is a "jack Hammer".   If you look at some of the other forums on my section...the GA glass or how to make a scraper...you can see that type blade.  If all else fails mill or grind the blade holder thinner.  no more then .062 at a time and then test it.   Those holders were generally made out of cold rll steel as the 150 series were made from tools steel and flex and don't bend like the cold roll.  Hopefully Paul, Mike  or Mel well come on and tell you about the blades we are using here in Oakland.  Erik, come on over Sunday and say HI.
PM me for directions.  Rich

PS:  I do not own a blade like the one you have.   H one more thing one of the students (Mel) has a Chineses mill we are going to scrape in...the ways look like heck...will start to put pic on new thread tonight.


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## Richard King

I was going to down load some pic's of day 1 and 2 the Oakland Class, but I was pooped out, will do it soon and today's class, I promise.   The class is going great...The Chinese Mini mills base ways were out .012" and we are machining it parallel now.   I would be careful buying one unless you want to plan on machining and scraping the ways after you buy it.   Have a nice day.  Rich....


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## komatias

Tonights project complete! I know am a proud owner of a 150 long scraper shank. Made it from 6mm gauge plate that I found in the scraps at work. 19mm wide, 150 long overall, thin section 2mm. The insert is the one that came on my sandvik scraper and so is the top of the clamp.

Tried a first cut on the base ways and am very very pleased! I don't have to worry about the blade kicking back, the cutting is more controlled and best of all, when I am not scared of the initial touch. Jack hammer be gone!!!! The other R60 stubby will be retired for use with the hand scraper, with the extra length I find I have better control.




Well worth the effort....

Thanks Richard!


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## Richard King

komatias said:


> Tonights project complete! I know am a proud owner of a 150 long scraper shank. Made it from 6mm gauge plate that I found in the scraps at work. 19mm wide, 150 long overall, thin section 2mm. The insert is the one that came on my sandvik scraper and so is the top of the clamp.
> 
> Tried a first cut on the base ways and am very very pleased! I don't have to worry about the blade kicking back, the cutting is more controlled and best of all, when I am not scared of the initial touch. Jack hammer be gone!!!! The other R60 stubby will be retired for use with the hand scraper, with the extra length I find I have better control.
> 
> View attachment 54774
> 
> 
> Well worth the effort....
> 
> Thanks Richard!



Now grind the blade with a tighter radius.  I would grind the bade  to a 60 mm radius.  It now looks like a 150 r.  Those flat blade tips can let you scratch the part when the corner of the blade digs in.  I tell my students those blade come ground to a 120 or 150 and those Sandvik are straight I think.  If your scraping soft gray iron grind the blade at a negative 5 deg on both sides.  One thing you can do with an clamp on insert is to grind all 4 sides of the blade.  You can grind a 120r on one side, a 90 r on another and a 60 r on 2 sides.  Be sure to use a 300 grit diamond wheel or finer to get a cut with no little scratches from a roughed finish blade.   With that new longer blade holder you will think your scraping butter.    A happy Scraper makes a good scraper ..ha ha   Rich


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## Richard King

I finally downloaded the pictures of the Chinese Mini Mill that Mel brought to the CA scraping class.  We first set the base on the granite surface plate and checked the 4 feet and the bottom of the base.  The first check and the feet were not touching on one side and hitting on the bottom between the feet.  Mel scraped and filed to get all for feet touching and the middle relieved.   Then we tested the ways and starting on the bottom right side we made it 0, the left bottom way was + .004, the top right side was +.009 and the top left side was .012"  so it came from the factory twisted .012".   Mel had taken a cut off the ways as they looked as bad as the top before he scraped them.  Spiral cuts that looked and I bet acted like a file on the mating saddle ways.

We then set the base on the Hosts Gorton mill  and fly cut them parallel to .001" and cut the top.  It was as if the factory had a dull fly cutter running super fast and it left circular grooves .060" apart.  The ways looked as bad.  It took .014" to clean up the top clearance.

Here are some pictures:


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## komatias

Guys,

Could someone please post a photo of a roughed biaxed surface prior to being deburred?

I am getting some very thin scrape lines with the new blade assembly after I ground the bit to R60mm.

Thanks


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## Richard King

komatias said:


> Guys,
> 
> Could someone please post a photo of a roughed biaxed surface prior to being deburred?
> 
> I am getting some very thin scrape lines with the new blade assembly after I ground the bit to R60mm.
> 
> Thanks



Those lines are probably there because your not using a fine enough diamond wheel.  You need to have a minimum of 260 grit, but I normally say 300 to 600.  Run the edge of your fingernail along the blade edge and see if you can feel little nicks.  It looks like the side of your blade is shiny, so that's not the issue.  On some brazed blades the black edge gets rough and can cause the small scratches, so I recommend you lap the side so it is shiny.    Here is what I can find now.  I will take a pic and add it later.  Rich    But the blade would look like this 
/\  but at 5 degree's neg. for soft cast iron


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## komatias

My observations so far:

the Biax doing 120 strokes/minute is too quick for me. The extra lines I was seen were from the overlapping strokes I was getting. I have installed a dimmer on the Biax cable and this makes life 1000000% better. Dont run if you can walk eh?




Following Richards teachings ( individual strokes and lines thereof) and some I got through the Machine tool reconditioning book I have been trying to drop the top of the saddle by around 0.08mm on two of the corners.




Still waiting for the 600 grit diamond wheel I ordered last week but in the mean time I used my lapping sticks in 200, 400 and 600 grit to get a good smooth blade surface.

As always, I will update as I go along


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## Erik Brewster

You sure are making progress! You scraping looks better every time you post. I've found that I don't need to slow the Biax down at all after some practice, but you are on the right track going slow to get some control before you speed it up.

It looks like you have some roughing to do, still (large sections still without spotting blue). Going to a larger radius can help removing bulk material. Then, when you are not roughing and instead are refining the spotting pattern, then go back to the small radius blades. The small radius blades will work fine for roughing, but the material removal is slower.

Your 600 grit wheel will make sharpening nicer, but it sounds like you have a fine workaround.


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## Richard King

Erik Brewster said:


> You sure are making progress! You scraping looks better every time you post. I've found that I don't need to slow the Biax down at all after some practice, but you are on the right track going slow to get some control before you speed it up.
> 
> It looks like you have some roughing to do, still (large sections still without spotting blue). Going to a larger radius can help removing bulk material. Then, when you are not roughing and instead are refining the spotting pattern, then go back to the small radius blades. The small radius blades will work fine for roughing, but the material removal is slower.
> 
> Your 600 grit wheel will make sharpening nicer, but it sounds like you have a fine workaround.




Also with the larger radius, be sure to keep the back of the scraper higher as if you allow it to be lower in the back the corners of the blade can gouge.  I say to keep the scraper level or up a little in back.  When you get tired one will let the back dip down and it will gouge.  Mant time I tease the new students I am going to duct tape it up in back to there side.  I have dreamt about using a gaitar strap to attach to it too....ha ha    This is why you have to not use your arms when moving side to side.  Be sure to move your body like your doing the dance the twist and not move your arms to tip the blade and gouge.  This is why I recommend a new student to use the 60 radius blade as untill they learn to control their movement the gouge the corners.   Thanks Erik for helping!    You are making me so proud of you as I want my students to pass on what I have taught them!  Good idea with the dimmer switch too.be sure the wires are big as small wires will cut down on the amps and the carbon brushes will wear or burn away faster.     Rich


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## komatias

Eric, thanks for the confirmation that I am proceeding correctly.

Richard, do you mean to keep the angle of attack high? As in the stroke of the blade to not be parallel to the scraping plane? I have understood about the control of the Biax from the body, it is very inconsistent when just using the arms especially after a while.

More fun tonight!

Regards!


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## Erik Brewster

Richard King said:


> When you get tired one will let the back dip down and it will gouge.  Mant time I tease the new students I am going to duct tape it up in back to there side.



Rich isn't kidding about letting the scraper slowly fall as you fatigue. You don't have to get the point of exhaustion for it to drop just a bit and it isn't a matter of strength -- more a mix of mental and physical fatigue. Even an all day scraping session (with the Biax) leaves me with physical strength to scrape, but I'm doing lots of dumb little mistakes at that point. A couple of tips on avoiding fatigue that work for me to keep mentally sharp when scraping for more than 10 min or so:

Stand on a soft surface. I have a rubber anti-fatigue mat that I stand on.
Lower the table or stand on a riser - whatever it takes to put the work where you naturally want to hold the scraper. Always make sure everything is secure (don't stand on something precarious)
Don't use the jackhammer blades
Figure out a way to approach the work at the +/- 45 degree angles without physically getting in an awkward position. I found an old milling vise with a swivel attachment works well. Sometimes I tack some wood scraps on the bench in two positions. No matter the solution, just find a way to be comfortable while being able to reach where you need.
Take a break if you do something dumb / out of character for you. It isn't punishment. The dumb move was probably your body telling you that it's tired.

I found it convenient to let my upper arm point straight down and hold the scraper end between your upper arm and body. If your arm is pointing straight down, there is no place for it to droop further.

Hope this helps.


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## Richard King

komatias said:


> My observations so far:
> 
> the Biax doing 120 strokes/minute is too quick for me. The extra lines I was seen were from the overlapping strokes I was getting. I have installed a dimmer on the Biax cable and this makes life 1000000% better. Dont run if you can walk eh?
> 
> View attachment 55085
> 
> 
> Following Richards teachings ( individual strokes and lines thereof) and some I got through the Machine tool reconditioning book I have been trying to drop the top of the saddle by around 0.08mm on two of the corners.
> 
> View attachment 55086
> 
> 
> Still waiting for the 600 grit diamond wheel I ordered last week but in the mean time I used my lapping sticks in 200, 400 and 600 grit to get a good smooth blade surface.
> 
> As always, I will update as I go along



I was scraping today and was thinking about your lines and how better they got when slowed down the speed.  You were getting chatter I think, That looks like a file sort of and you get chatter from holding it to long in one place and digging.  So when you slowed down the speed, your scratches disappeared.  Another thing you need to check is your stone because the outside edges look low.  You will be shocked if you set your flat stone on the granite and hinge it, The majority of stones are hitting on the ends on one side and high in the middle on the other side.  It looks like you using the side that is high on the ends and your getting a convex surface.  Take a magic marker and mark the edges and stone it and see if it comes off.  In the last CA class I broke one of my stones in 1/2 because it was warped.  MS-24 Norton tapered slip medium grit Indian stone.   Sometimes if the blade is dull you press harder and get chatter or you have the tip sharpened to flat.   Lots of variables to learn and what to look for.

Happy Scraping.  Rich


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## komatias

You guys seen this?


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## komatias

A little update:

Today I finished the saddle. It is now parallel to 0.01mm which is the accuracy and resolution of my DTI.

The DTI is a pile of crap. I could not trust is so I had to keep measuring my zero every so often to ensure I was not deviating.

Following the discussion about the stone being concave, I have moved to a deburring file. makes clean up after deburring easier too, no more stone dust. Have spun it on the table and it seems flat enough. 

The results:


Richard, may I be added to your honorary students list now?


Decided to start on the base again. First order of business is to establish if datum A is actually worth using at all.

Put the 1 2 3 blocks at the edges of one side of the long axis of the base and used the surface gauge and DTI on the other. Seems there a dip of around 0.08mm in the middle of the ways and the extremes are out by 0.04mm. 

Out came the 90mm jackhammer. but now I have the springy blade, I bolted the jack hammer onto the springy blade...Great Success! As the area is so large, I was able to increase the stroke and speed to maximum. The idea is to cut the surface of the datum so it can carry.

Blued up the camelback and did the union jack check. Each long side is flat (just) where blued but there is definitely some warpage going on. Not much but enough to **** me off, especially after I have learned so much and manage to get the saddle so good. This was also confirmed by putting the 1 2 3 block along the surface and placing the camelback on them. the left hand one was held flat and perfect while the right hand one would rotate about one corner.

So now I need a small cast iron surface plate to flatten Datum A.

I may have to attack the straight edge again next. Now the I am better at scraping and while waiting for this months paycheck.....


Thats it for this week folks, not going to be in the shop until Monday.

Have a good weekend!


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## komatias

Hello everyone,

I thought I would let you all know that  I have had some some time to reflect on things. 

Scraping is good and fun, however it is hard work. When a hobbyist undertakes scraping it is usually because grinding is so expensive or difficult. In my case, after starting and progressing with the machine, I have found that I would need to shift too much material. Having spoken to a number of people in the trade, the consensus seems to be "Buy a new one". The quotations for the bare minimum of grinding all seem to be around the same price as a new machine.

Now, considering that I want to convert the barsteward to cnc, and have already got all the goods I was faced with 3 options.

1) Bite the bullet: Grind and apply turcite (£2200)
2) Keep scraping and apply turcite (4 months of evenings, figure out how to fix the dovetails, make a dovetail prism etc etc....)
3) Mill the bugger to within scraping range, scrape it flat/parallel/square and apply linear rails ( 1 month of evening, £600 in rails, £100 in extra materials to increase the travels).

As you may have guessed, the last option is the one I am going for.

I have access to machine tools and a biax so as long as the machine tools can get me close, and I have 90deg angles, I can proceed with good speed. Added benefit is the elimination of any set warpage that came with the machine.

So today I have started eliminating the dove tails on the base. The datum faces will be the front of the base and the clearace plane that I have scraped flat to 20dpi already.

Here I am zeroing on the front face. I guess I could have clocked on the dovetail but knowing how out they are I would just be wasting mu time cranking the wheels. Only one clamp to get a pivot point. The base must weigh around 90kg with the extra ballast I put in it a while ago (epoxy sand and gravel)




The milling machine I am currently using is my old trusty RF30 which give a surprisingly good accuracy when I make sure I account for slop/inaccuracy in the ways.

This is where I got to before curfew:




A preliminary model of what I am going to achieve
.
	

		
			
		

		
	



And before anybody says anything, the y-rails will be supported before I am done.

So the project is now a " Make a cheepo mill, into a machining centre"  pigs ear to purse, Cinderella story. 

Will keep updating as I go ahead.

Question for Richard, (as usual) since he has taught the Taiwanese to do exactly this: is 5DPI good enough or should I try and get 20-30dpi for the rail mounting surfaces?


Regards


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## Richard King

The Linear ways I have installed had a Positive side that was straight and parallel to the base .00005"/12" as they were being installed at Quasar Machine who was at that time the OEM for Bridgeport and their CNC machines.  Jig Bore spec's.  We scrapped them to 10 to 15 PPI 80% static fit.  The closer the base is the better the rails will machine.  You need to decide how good you want your machine to cut.  Plus check with the mfg of the rail how good they say their rails need to be.  I teach for a static fit surface or now way surface we scrape them 2 to 5 PPI (points per 1 sq. inch) with 80% contact.  I scrape normal but over stone the scrape to eliminate the 50% contact we try to get on lubricated ways.  I sill see if I can attach some pictures of how we used a granite straight edge to align the positive side of the pair of rails.  Those steel rails bend and need to be aligned straight, they are not straight and you bolt them on.  I will add a couple of more after I find them in my laptop gallery.  In Taiwan we made a miniature machine that had bolt on ground ways we would scrape turcite to,  we had bolt on ways we scraped to bolt linear ways to and align to the granite square.  That reminds me you will need to square your X and Y axis too.    It's getting late and will add more tomorrow night.  Rich

Rich


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## 4GSR

Richard,

I have to ask, Is the floor in that factory painted that "green" color?  That's almost the color I've painted my lathe to.  Is that suppose to be easy on the eyes while working?

Ken


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## Richard King

That picture was taking in a research training center in Taichung Taiwan where I taught several classes.   I have no clue about the color and how meaningful it is to your happiness of making it zen moment.   Here is their web-site.   The 3rd line link goes to the list of classes I taught there.  I m in several of the pictures.  PMC and I planned the format of the class.  Take a look at the scissor tables they built so the height could be changed.  Some pictures show using a granite straight-edge to indicate to check where the linear ways bolt to.
The translate say Name of Babe..  a real whopper of a tranlasation error.

http://scraping.pmc.org.tw/share.php?display_type=list

Rich


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