American Pacemaker -- learning to scrape V-ways for alignment . . .

[Archie Cheda]

After a four-year project scraping the ways (& otherwise restoring) a 100-year-old Lucas horizontal boring mill (HBM) for the Machine Shop Museum at Tuckahoe, I am now undertaking a similar job on my own 14x54 American Pacemaker -- it is only 66 years old. I thought that the techniques necessary to get both alignment and bearing would be of interest to the readers of this sub-forum. (I am currently discussing the overall project on "another forum", but there are details I am leaving out that might be of interest to folks here.)



First -- I am not an expert or highly-experienced scraper, but I have been in shops all my life and I am as old as my lathe. I taught manufacturing engineering for twenty years and feel strongly that much of working in a shop is related to having a good mix of experience and theory -- understanding both the "how" and the "why". I am not an efficient scraper, but my experience on the Lucas has given me confidence that I am in control of what I am doing, even if I am slow. Below I am using a Biax power scraper, but for me at the present, alternating hand-scraping with power scraping seems to work best -- both for saving my muscles and for maintaing control on those narrow V-way surfaces:



In order to spot and scrape on a horizontal surface during the many hours of rough scraping, I welded up a sturdy table to support the heavy lathe bed:



It has two adjustable legs for leveling and can be picked up and moved around loaded using a pallet jack. I will be doing the finish scraping with the lathe bed supported in its normal position. In the center of the pic you can see a jack that allows me to take any twist the bed takes on in this position. I measure the twist using this Starrett level which has been mounted on a B&S magnetic surface gage:



The level also lets me double check that I am not "tipping" the way surface as I do my roughing. So far, my technique with the straight edge seems to be preserving the angle, but I feel better checking as I go along to having to make a major correction later on.

I found that the vertical rear machined surface adjacent to the ways and the top of the ways are possible reference surfaces, I am using this ad hoc measuring tool to measure the progress on scraping the less worn portions of the way surface:



I am not depending on any one reference or kind of measurement, but am measuring several ways and comparing the results. I did spot and lightly scrape on the rear vertical surface and it seems to be a very good reference. The narrow top land is the surface that ATW (American Tool Works) recommends for leveling the lathe and it was planed along with all the other surfaces. I found that measurements using this surface were mostly in agreement with others, but there were small zones where a machinist probably did some light filing to dress off signs of damage to the machine ways.

The pic below shows how I did an initial survey of the ways and how I am double-checking the results as I scrape in the second surface of the rear-most V-way pair of surfaces. The V-block is custom-made out of a small piece of cast iron and is scraped to the V-way. The machined surface that the saddle gib sides by without much contact also seems to be a good, unworn reference. (I found this true of the Lucas HBM and my Pacemaker -- it may not be true of more lightly built machines.) My initial survey showed the expected wear zone starting a few inches out from the headstock end, reaching a depth of some .015" about a quarter of the way down the bed, and sloping up from there to an unworn few inches at the extreme tailstock end. The measurements shown above showed the same pattern, but with each way deviating around .010" from the unworn portions. Doing the trig gives a very close agreement.



In the background, you can see my six-foot straight-edge. It is a composite piece with the main I-beam made of aluminum with cast iron clad on the working surfaces. I used my five-foot B&S camel-back straight edge to scrape it in -- it is similar to the four-footer in the first pic above. The six-footer actually weighs less than a four-foot cast iron camel-back B&S straight edge.

More detail: When working on each surface, I was presented with around four inches of unworn way surface at the extremes of the 88" length of the carriage ways. This is a classic case of "scraping straight down". I started using shorter (18", 24", & 36") straight edges and although I blued the whole straight edge, (after dressing dings with a fine file) I spotted the straight edge with its center of gravity over the center of area of the unworn land. This printed ink only on the unworn area and as I cycled through spotting and scraping, the area picking up ink grew toward the center. (This depends highly on very consistent and even scraping. I used a very ritualized series of power scraping at 45-degrees left, 45-degrees right, and heavy hand scraping parallel to the way length, each followed by a uniform dressing with a mill file.) Once my six-foot straight edge would span the gap between the end lands, I used it, alternating one end and the other. I was quite pleased at how well this worked -- only very small corrections were necessary as the scraping proceeded. The pic above was taken when there was still about three feet of low area in the middle between the lands. (There is about ten inches of blue at the far end, but it is hard to see in the pic.)

I now will do an "advertisement" for Richard King's Dad's King-way Alignment Instrument. I was fortunate to do my first major machine tool scraping project on a machine that had rectangular ways. I could use a straight edge along, across, and diagonally on the main horizontal way surfaces. Keeping the narrow vertical surfaces straight was easy using a straight edge and measuring the angle with the horizontal ways. The two vertical ways were parallel and near enough to each other that all I had to do was to use a micrometer caliper to measure them directly to keep them parallel.

V-ways are a much larger challenge. There has to be a system to keep the V's parallel -- the Pacemaker has four V's. Many machine tool rebuilders use the saddle and tailstock base from the lathe itself as masters for this operation, but this only keeps them parallel in pairs, so there is still no direct way to make certain that tailstock and carriage way pairs are parallel. This brings me to using a King-way Alignment Instrument or its equivalent -- over the next week or so, I will be making my own version of such an instrument. I will also be making an adjustable test bar, similar to that recommended by Connelly.

In finishing, let me say that I am "working without a net" here, but to use another old saying "it is OK to be in over your head if you know how to swim". If there are any questions or comments, I will do my best to answer, knowing that it will all be in the spirit of the "friendly machinist forum".

Archie

P.S.: To Richard King -- your efforts on this forum were what inspired me to join. Thanks once again for your encouragement.

 

[Richard King]

Welcome to the forum Archie and it's nice of you to share your expertise with us. For everyone's info I met Archie a few years ago when he was up here in MN picking up a part from a mutual friend and when I was out teaching in Machanicsburg PA at a Defense plant. He and his lovely wife bought me lunches. We spent a few hours talking about scraping and Fulton Holtby a professor who taught Engineering up here at the U of M for 41 years. http://www.dunnhistory.org/sitest.html . I love to talk as many of you have already guessed and I loved talking to Archie.

Archie is a great teacher and He sent me photo's of the Lucas and it is a vintage machine, what 1900 something Archie? I hope to teach you someday and show you how to scrape with the Biax without using a hand-scraper. I still use my hand-scrapers as in some small areas like a dovetail on a lathe compound it works better then a Biax.

I'm not sure you want some help, but I would suggest you look into your Biax Blade kit for a 6" long 20, 25, or 30/150 series blade it is more flexible and doesn't give as much chatter and doesn't shake you to death. I tell my students that blade is like holding a jack hammer. I never use those short blades in my Biax, I use a #30 in my hand scraper to 1/2 moon oil flake. 1 in a 1000 use them for finish work. if I have the condition your calling "unknown land is not unknown by me, I would use your Bushe Precision aluminum / cast straightedge to bridge the gap and use a feeler gage to discover how low it is. Then I would step scrape it down. I do some detecting work as I am sure you did and scope it out or measure all the ways before you scrape to get a "game plan". I want my students to draw sketches, mark the bed with a marker....really plan out the plan of attack.

You can do the math in your head. The average depth or whats removed by a scrape is usually .0002" with a 150 series blade and .0003 with the short #20 blade like the one your using. If it is low .010" with a feeler gage and is consistently going up on each side say .001" per foot you divide the sections up 12" long. Then I take a magic marker and mark a "NO SCRAPE" the middle 12" lowest spot and then every 12" each direction I make a mark in the clearance section between the ways and number it as the following if it is the bed. I always have my student scrape a part in class so they know exactly how much they can scrape off per pass. Just for this reason because some big muscled student may take off .0005" per pass and a med sized student might only scrape .0003" .

end of unknown ________3____,______2______,_____1_____,no scrape_____1_______,______2______,_____3________,end of unknown

Then use redlead or the yellow canode mixed with glass cleaner to dilute it to put a thin layer applied with hard felt and wiped off leaving a colored film to dull the metal. on it so you I can "Blind" scrape the bed in a controlled way. So start on the out side and scrape one time from the unknown to unknown and not touch the middle, wipe it off, stone it and red-lead it up again from 3 to 3, scrape, then, then 2 to 2, then 1 to 1. Your taking .0002 per scrape off, so you just removed 4 x .0002 = .0008" each pass. Then I would step scrape it 9 more times or 9 x .0008" = .0072.

Then put your long straight edge back on and finish the bed way using it to bring down the way scraping blue spots. If you want to you can scrape it down a little more before bluing it, depends on how confident you are with your skill. That will speed up the work. I call that step scraping using blind scraping to rough it down before bluing it up. A beginner can use your blue gage to keep it from loosing the angle, but I just use the yellow Canode mix / red lead substitute as a guide so as I scrape off the yellow I don't scrape it again. I always scrape the tail-stock (TSW) ways first as they do not wear as much as the saddle ways (SDW). The ways under the head it sits on and the far right side seldom see wear so I use the the TSW as my base or first set of ways to scrape the rest of the bed parallel to. So as I said scrape TS V- way worn the most first, then TS next V way, then SDW that is worn the worse and then the next SDW flat and parallel. Once I have the flats done I use the King-Way to find the low areas and rough scrape it with Canode mix, etc. You way works, but it is slower.


In the classes I teach hand-scraping as it is easier to learn to run if you walk first. Plus the new Biax's are expensive. Thanks for joining us Archie and you will find this bunch of people are polite and are hungry for information. Many here also are Engineers, tool makers, machinists and want to share. Thanks for the kind words. Rich
PS: I love the 3 point stand !!

 

[Archie Cheda]

From over-measuring to blind scraping . . .

Richard,

The Lucas at the Tuckahoe Machine Shop Museum was new in 1912 -- I got it operational again in time for its 100th birthday last year. The story of its restoration is detailed in a thread on another forum.

I did experiment with a borrowed Biax when working on the Lucas, but I am a hobbiest and find that I most enjoy the peace and quiet that comes with hand scrapping. Fortune provided me with a gifted Biax, so I am (using your DVD heavily) slowly integrating power scraping into my hobby. At this point, I like to alternate. I brazed up my own blade and once I have made a variety of blades with different radii and stiffness, I expect to increase the percentage of power scraping. Thanks for the blade suggestions -- I limit the amount of $$$ I invest in my hobby, so I will be making them myself. Being able to do this is also a part of the hobby for me. By the way, I'll take all the help I can get . . .

I am leaving out a lot of details, but will reveal them as the readers of this thread stimulate me to do so. First I used the V-block as shown earlier to survey the ways -- see below for the plots of the front & rear saddle ways. Once I could bridge the most worn area I did a thorough feeler gage survey -- I did not capture the data because it was pretty much the same as the initial survey. The engineer in me enjoys collecting the data and the machinist likes to have the extra confirmation that everything is in control. If I did this job regularly, I would not need to do so many measurements, but it all boils down to the old adage: "measure twice and cut once".



I also agree with marking up the bed -- I probably have at least a dozen generations of chalked numbers on the bed as I proceeded this far. I only reduced the data shown above to a plot, because all the other generations supported this initial survey. A number of times a slight divergence in the numbers allowed me to correct for some "drift" before it was much additional work to correct. Speaking of corrections & lessons learned, I will diverge with a story from my earliest days scraping on the Lucas bed:

I was working the main way surfaces on the Lucas HBM -- two flat ways that were in the same plane, 4" wide and 6.5' long. A survey revealed that the 96-year old ways, rusted by two years of uncovered storage out in the weather, were actually only worn .002" near the column and were unworn for the first 6" at the other end. (This may not seem like enough wear, but, depending on the work being done, the position of the saddle on the bed might not be changed very often -- this machine did not even have the optional power feed on that motion. In addition a crash had taken several teeth off a miter gear in the main drive -- my theory is that this happened many decades ago and that Lucas actually had a long "vacation" before Tuckahoe acquired it.) In order to remove the worst of the deep scoring I actually lowered the surface .005" -- this amounts to removal of two cubic inches of cast iron. (The upper saddle & table bottom ways showed a lot more wear, consistent with the normal power feeding of the table.)

I started out spotting with what was then my longest straight edge -- a four-foot B&S camel-back. This is kind of short for a 6.5' way -- I figure that it takes not two, but four times the time to do alternate spotting and scraping so that the ends and the middle all stay in the same plane. For the first two thousandths I also had to "step-scrape", but I found that was not as difficult as I expected. I did not have much trouble scraping progressively heavier as I worked toward the end that had to have the most material removed. This was facilitated by the fact that all I had to do was use a micrometer caliper to measure the thickness of the way.

The "other" direction, across the ways, seemed to me at this naive stage in my scraping "career" to be a good candidate for a surface plate and I had one that just spanned the two ways. I did this for the first half of my scraping, but at one point I decided to check by placing the four-foot straight edge across (& diagonally) the ways. I was shocked to find that I only was printing on the outside edges! A bit of thinking brought me to the realization that the unsupported portion of the heavy surface plate was drooping. It did not help that it was inverted from the position it had when it was scraped in. This "droop" was probably only a ten thousandth or two, but it made a large difference in the spotting pattern, giving me a new confidence in how sensitive this process is. I also learned that bringing those slightly tilted surfaces back into parallel was a lot of extra work.​

I appreciate your exposition of "blind scraping" -- now that I have done the rear V-way and gained confidence, I will try it on the front V-way. I did not mind the extra time I spent spotting because it gave my muscles some time to recover between passes. I also did roll on my yellow Canode avery few passes and then "wail" on the way surface for one pass, followed by dressing it all off with a file. As I go along I will get the confidence to do more blind scraping during the roughing process.

I chose to do the saddle ways first for a number of reasons, some of them very minor or even not really logical. The main thing is that once I have the saddle scrapped to its ways, I can then use the saddle as a measuring fixture for perfecting the tailstock ways (which are also the headstock ways). The carriage ways extend under the huge headstock and would be a bit of a stretch for my six-foot straight edge, while the 88" length of the carriage ways is a much easier proposition. The large weight of the saddle will make for a very stable measuring platform and I may even rig a small cutter slide to do some truing of the worn ways remaining by using the lathe bed & saddle as a hand-powered planer. I believe that this has been done using a tailstock base, but it should be much easier with the saddle, although I will have to do the cut in two pieces because the tailstock ways are longer than the total stroke of the saddle.

Regarding the bed stand, I find it to be very useful. One important data point will be how much the shape of the bed changes when I re-orient it to its normal position. I will be carefully documenting exactly how much things change when I re-orient before finish scraping. It may be that the Pacemaker bed is so darn stiff that there is no change, in which case I will use the stand for all but the last few passes of the finish scraping.

I hope the readers of this thread are having as much fun as we are,

Archie

 

[Richard King]

I see your supporting the bed with 4 x 4's at what looks like 30%. That's what I use too and for my 3 point location(s), as a PHD Engineer named Richard Visnor who was part of the Honeywell Think tank years ago told me to use. He and Paul Arneson a MA Engineer of Professional Instrument (Air Bearing, Inc.) who I also talked about it before I presented a paper for the SME at the IMTS show several years ago. I knew the principal but not the terms. The 30% location is the "Rotation of Points" and 3-points is the "kinimatic mount principal" . My dad used to say 1/3. Starrett / True-stone uses 25% as they say that's what the national standards are. Richard V said if it was a square no matter how long it was you would use L x .707 divided by 2 to find the points from each end.

Then he said because we are working with a rectangle of different thickness to use 30%. It has always worked for me. Unless the casting is not a triangle shape. Then I lay it on a round bar on the floor, then set the casting on the bar to find the center of gravity to determine the 3 point location. You I am sure could add to this seeing your a retired Engineer and Professor. (but might put some of the readers to sleep, ha ha)

I was just thinking you should set the bed down after you scrape the first first flat of the V. Supported where the machine legs are going to attach and see if it sags. In another thread on another forum we talked about how Sip leaves its cross rail ways high in the middle, so as they attach the saddle, the the ram and it sags down as it wears ,it gets better. Much like I say on the front of a knee on a knee mill I leave it high so as I load up the saddle, table it sags square. or the front side of your tail-stock Ipoint them up. Lots to talk about. But getting back to the lathe you might want to support it a little further out with the 4 x 4's so when you put it back on the legs it will be a bit convex and sag straight because the legs are at about 80% and not 30 %. Lots to think about and have fun. Rich

PS: I added my 2 cents worth now. It's your thread in our forum. I'll stand back and read and add some comments when I think I can share some important info when needed.
Rich

 

[Archie Cheda]

Airy points . . .

Rich (& everyone else),

You are correct in your assessment -- I am supporting the lathe bed as near as was practical to the Airy point locations. I just did a more precise calculation in dealing with the scraping in of my Busch Precision composite level. I only had to pay $100 for it, but it had not been stored properly and had about .005" of bow over the six feet of its length. I needed to scrape it in before I used it and I needed to properly support it while scraping it in. So far I only scraped in one side and will re-visit it again before the finishing phase. I have a little-used five-foot B&S that is a good reference for scraping in the Busch but it weighs at least four times as much -- just moving it around is a pain and I left it supported on its wooden blocks and brought the lighter straight edge to it for spotting.

In reality the Airy points are not quite what everyone thinks that they are, but are still useful for a "standard" way to support a horizontal beam-shaped part or tool. The pure theory that the Airy point calculation is based on assumes a simple beam of rectangular cross-section. Already the Busch straight edge is not the same with its I-beam section, vertical ribs, and lightening holes -- a camel-back straight edge is not even close to the assumptions. For the B&S straight edges, I support them on the wooden handles when using them with the working face oriented upward and the cushions they rest upon in their storage shoes are at about the same points.

The rest of the background of the use of the Airy points for support is that the intended function is for end-measuring standards. Such a rod (long, skinny beam) must be supported in some simple manner that can be easily duplicated. The critical requirement for a measuring rod is that its ends must always be exactly parallel and any support system that causes the ends to not be parallel introduces error by the fact that non-parallel ends have more than one length depending on where on the end contact is made plus the droop of the rod between supports which shortens the length of the rod. The "best" way to support an end-measuring would be to support it uniformly all along its length -- this would not be practical and so was rejected at least 50 years ago by the major international standards bodies. Ideally (if the assumptions of the beam cross-section are met), suspending measuring rods by the two Airy points allows a sag on outside of the support points to be counter-acted by the sag in the middle, allowing the ends to remain parallel. (See page 123 in Moore's "Foundations of Mechanical Accuracy" for a good illustration of this.) The fact that there are three droops subtracting from the length of the end measuring standard is accounted for by supporting it by the Airy points during its manufacture, so the rods are actually longer when supported uniformly or hung vertically. Note that this is not exactly the problem we are dealing with when using straight edges.

What is most important for straight edges is to use them supported in the same manner in which they were scraped. As I started gaining familiarity with my first four-foot B&S I came to trust it and know what to expect. Many might laugh at the thought of me "becoming one" with my straight edge, but I expect that the more experienced scrapers will know what I mean. Like so many subtle things in the shop (& elsewhere), those inanimate objects are "talking to you" if you only take the time to listen. For example: In winter I like to park whatever I am working on in the sunlight pouring in my 12'x12' south-facing transparent shop door. This gives me excellent light and I do not need to heat the shop up so much to be comfortable. When I did the Lucas scraping, this worked fine until I got to the final phases of finish scraping and found that the spotting patterns were all over the place. Thermal effects on the mill bed and the straight edge were at play and went away immediately when I moved out of the sunlight and allowed everything to reach the same stable temperature.

Another example: A Tuckahoe friend had an identical four-foot B&S which he lent to me to check against mine. At this point I had the Lucas bed to the point where it and the two straight edges could be used as a version of the "three plate method". It turned out that my friend's straight edge was fine except for less than one square inch at one corner which did not print, probably because someone dropped it on that corner. I marked that corner so that it could be ignored because I did not see the point in removing a lot of the working surface just to bring that tiny area back to the ideal plane. I did some spotting and learned how important the flaking texture is on a straight edge. My B&S was in virtually unused condition when I bought it, with a beautiful diagonal checker-board flaking, while my friend's was worn to a smooth surface which could have been ground, but did not even show any "lay" to its finish. My straight edge only needs addition of ink after quite a few spottings -- I just re-roll the same ink with my soft "speed-ball" roller. I had to apply more ink every time I spotted with my friend's smooth straight edge. Now, (finally getting to the point), my friend's straight edge had a ground steel plate added to the peak of its "hump", mounted quite firmly. At first I did not know why someone had bothered with this modification -- folks have suggested it was to use with a level when there is a need to bridge a large distance. My assumption was that it was a much more stable platform when orienting the straight edge face up for inking and it was convenient. I left the straight edge parked this way while scraping and found that even though my straight edge pivoted properly on the Lucas bed way (something Richard teaches everyone), and my friend's printed and pivoted correctly at first, after sitting on the center of its "back" my friend's straight edge pivoted very freely about its center. If it were left a while supported properly on its two blocks, it would again pivot and print properly.

Finally (!) my take is that straight edges most like to let their flat surface "cuddle" up to another equally flat surface. At the limits of sensitivity of a very thin spotting medium, this affect allows one to wring unbelievable amounts of accuracy out of this system. Our work and our standards are elastic and will deflect if given any opportunity. All this time I have "had my teaching had on" and I am not making these statements to be written down as fact -- no thinking required. I am attempting to take you along the path I followed, getting to have a better feel and understanding for scraping. I am still far from being an expert, but I have made similar journeys before and I am trying to share how I proceed . . .

Archie

P.S: Because Rich will be sitting on the side-lines for a while it is up to others to help me proceed in this thread. I will post my progress on the project, but a few questions will go a long way to bringing about maximum sharing of information.

Is anyone wondering about what a speed-ball roller is?

 

[EdR]

Re: Airy points . . .

Rich (& everyone else),

P.S: Because Rich will be sitting on the side-lines for a while it is up to others to help me proceed in this thread. I will post my progress on the project, but a few questions will go a long way to bringing about maximum sharing of information.

Is anyone wondering about what a speed-ball roller is?

Yes, I am.

And am enjoying this thread, so many thanks to you for taking the time to share this project with us.

EdR

 

[Richard King]

I decided to contribute as I am one of the Forum moderators and help when I see some other methods can be used too. As I have in all the other threads started here.

 

[Archie Cheda]

What is a speedball roller ? ? ?

Ed,

I am just an amateur, so anything I share in this forum is what has worked for me and should not be taken as advice from a professional. In some craft hobbies ink is applied to woodblocks to make prints. A modern means of applying ink is to use a rubber roller, called a "brayer" in the hobby. Others have used rollers to apply spotting ink when scraping before me, but here is what I do:

Using a small (4" x 6") smooth flat non-porous pad to which I apply very small quantities of the Dapra water-based ink. I then roll the ink out on the pad and use the roller to apply the ink to my master (in this case a straight-edge). This procedure is neat and allows very good control of the amount of ink transferred to the master, allowing a very uniform and thin film of ink to be applied. If the flaking on the master provides a good texture, it stores the ink well and I ca re-roll the master through many spotting cycles without adding any more ink to the roller. (A very smooth master needs addition of ink much more often.) My final tip is to get a soft roller. A hard roller will work, but a soft roller brings an additional benefit: any grit or other small piece of material that could interfere with getting a good ink print sticks on the roller. I think it is the stickiness of the ink on the small radius soft rubber roller that gives this effect when it is rolled along a smooth flat hard surface. From time to time, I use warm, soapy water to clean the roller, but the inked plate and master stay clear of particles for much longer. I do not see this effect using a harder roller.​

If you want to buy one go to a local craft store or do a search for: speedball brayer

Archie

P.S.: I will be tending to some personal duties the next few months, so my progress on scraping the Pacemaker will be slow.

 

[Richard King]

Re: What is a speedball roller ? ? ?

Ed,

I am just an amateur, so anything I share in this forum is what has worked for me and should not be taken as advice from a professional. In some craft hobbies ink is applied to woodblocks to make prints. A modern means of applying ink is to use a rubber roller, called a "brayer" in the hobby. Others have used rollers to apply spotting ink when scraping before me, but here is what I do:

Using a small (4" x 6") smooth flat non-porous pad to which I apply very small quantities of the Dapra water-based ink. I then roll the ink out on the pad and use the roller to apply the ink to my master (in this case a straight-edge). This procedure is neat and allows very good control of the amount of ink transferred to the master, allowing a very uniform and thin film of ink to be applied. If the flaking on the master provides a good texture, it stores the ink well and I ca re-roll the master through many spotting cycles without adding any more ink to the roller. (A very smooth master needs addition of ink much more often.) My final tip is to get a soft roller. A hard roller will work, but a soft roller brings an additional benefit: any grit or other small piece of material that could interfere with getting a good ink print sticks on the roller. I think it is the stickiness of the ink on the small radius soft rubber roller that gives this effect when it is rolled along a smooth flat hard surface. From time to time, I use warm, soapy water to clean the roller, but the inked plate and master stay clear of particles for much longer. I do not see this effect using a harder roller.​

If you want to buy one go to a local craft store or do a search for: speedball brayer

Archie

P.S.: I will be tending to some personal duties the next few months, so my progress on scraping the Pacemaker will be slow.

I am glad you came back Archie, I was worried about you. The site crashed and Nelson said your last couple of posts were lost I promise to not say much on here, but as Moderator I have to. Your a craftsman and please stay in touch. Many of the readers and I have missed you.

Rich

 

[EdR]

Re: What is a speedball roller ? ? ?

Thanks for the tip Archie, I have been using a hard black rubber brayer, rolling the dykem out directly on the granite or straightedge. Will be interested in seeing the difference in the softer rubber.

I also intend to follow up on your and RK's suggestion (on his dvd) to try the dapra yellow contrast medium. I've never tried it (and, at 59, could benefit from any technique that makes spotting easier to discern).

EdR

Ed,

Using a small (4" x 6") smooth flat non-porous pad to which I apply very small quantities of the Dapra water-based ink. I then roll the ink out on the pad and use the roller to apply the ink to my master (in this case a straight-edge). This procedure is neat and allows very good control of the amount of ink transferred to the master, allowing a very uniform and thin film of ink to be applied. If the flaking on the master provides a good texture, it stores the ink well and I ca re-roll the master through many spotting cycles without adding any more ink to the roller. (A very smooth master needs addition of ink much more often.) My final tip is to get a soft roller. A hard roller will work, but a soft roller brings an additional benefit: any grit or other small piece of material that could interfere with getting a good ink print sticks on the roller. I think it is the stickiness of the ink on the small radius soft rubber roller that gives this effect when it is rolled along a smooth flat hard surface. From time to time, I use warm, soapy water to clean the roller, but the inked plate and master stay clear of particles for much longer. I do not see this effect using a harder roller.​

If you want to buy one go to a local craft store or do a searcg