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Rebuild - Part 2

Moving the Shop

Moving the Shop 2

Bringing Home a Sheldon 12" Shaper

Sheldon 12" Shaper 2

Sheldon 12" Shaper 3

Sheldon 12" Shaper 4

Sheldon 12" Shaper 5

Sheldon 12" Shaper 6

Sheldon 12" Shaper 7

Sheldon 12" Shaper 8

Sheldon 12" Shaper 9

Way Alignment Tool



Email Jim


Sheldon 12" Shaper - pg. 3
July 23 - August 17, 2015

In the last installment, I had started scraping the bottom of the vise body due to the top of the vise rails not being parallel with the shaper table. The first picture below shows the bottom surface pretty much as I got it. I had scraped off a couple dings in the upper right corner and scraped/cleaned off some dried crud from the circular area where the bottom of the vise body surface makes contact with the ring on the top of the swivel base. I had also scraped the little bit of metal on the lower left edge of the casting that was preventing the rest of the surface from touching the surface plate. As you can see in the expanded picture from the small amount of red Canode ink on the upper right and the  lower left edge, there's not much contact with the inked surface plate. It appears that the vise body has warped. The cause of the warpage may be that some swarf got trapped under the ring that contacts the vise body or maybe the jaw was cranked down too hard on an uneven work-piece. The end result is that it isn't flat. Unfortunately, I forgot to try some feeler gauges under the corners opposite of where it shows color so I could have a record of how much it was warped.

This is the bottom of the vise body as received with only a little scraping to clean up some dings.
Color in upper right and along the lower left edge.
I have a few cycles of scraping on the vise body and we still don't have color in the upper corner.

 After I had scraped a few scraping cycles, I put the vise body on my best surface plate and measured the relative height of the different areas of the vise rails. I then moved it back to the smaller plate I use for marking and took the picture (left below). You can see a line, parallel to the cast jaw, that separates the original height of the rails from the worn or re-worked area. In the lower left of the picture, the original surface under the fixed jaw's removable face is 0.0006" higher than the worn area to the right of it. On the other rail (top left of picture) the difference has grown to 0.0037". Even without taking into consideration that the vise body had warped, the difference in height between the two rails is enough to cause errors in machining parts.

A couple of scraping cycles later, I remeasured the tops of the rails again. The second set of measurements were very similar to the first. Trying to measure to ten-thousandths on a less than smooth surface makes duplicating the exact same measurements almost impossible, but they're close enough to let me know that I need to get the bottom of the vise body flat and machine the top of the rails.

The vise body is on the small plate I use for marking. The numbers are the relative height in thousandths as measured on my large plate.
After a few more cycles of scraping, the measurements of the relative height are much the same. The top of the rails will need some work.

After a few more passes of spotting with the red Canode fluid, I decided that it was time to switch to Dykem Hi-Spot Blue. I like the Dykem product better than the other brands of oil-based Prussian blue I have tried. It seems to have a less greasy consistency than the Permatex brand and retains its color better when rolled on thinly. I also tried some stuff from a seller on Ebay that I liked less than the Permatex. While a thin coat of blue is better for refining the number of points per inch, it comes at a price. The price is that it is very hard to see the ink spots on the shiny scraped surface. Getting your lighting at a proper angle helps, but applying a contrasting background color to the surface you are spotting seems to help me more. I used yellow Canode spotting fluid rubbed on and then buffed with a dry paper shop towel in order to leave the smallest amount that still puts a yellow haze on the scraped area. I then place the work on the thinly inked Dykem covered surface plate and rub it very little to transfer the blue on top of the yellow. The more you rub the work on the inked surface plate, the more that the Dykem Hi Spot builds up around the high points. This makes the area around the points easier to see, but the increased spot size makes it tougher to just scrape the tops off of the high points. When switching from the thicker Canode red to the thinned out Prussian blue, you get a much truer picture of the contact points per inch. After the switch in marking mediums, I was now showing a lot more space between the marking spots.  I scraped about a dozen cycles with the Prussian Blue and yellow before I moved on to the last marking technique.

This was taken after some more cycles. I'm beginning to get some better coverage. I still have some sparse areas, but they're beginning to fill in.
I have switched to rubbing on a background of yellow Canode and spotting with Dykem blue. I rubbed more for this picture to show the spots, but the camera didn't catch the lighter blue spots.

The last technique I used to mark for finish scraping is reverse spotting. With this method, you apply the spotting fluid directly to the work. I like to use the Canode ink for this because I can buff most of it off with a shop towel and end up with a very thin layer of the ink. The thin coat water based Canode also doesn't transfer to my clean surface plate as much as the oil based Dykem. You then rub the work on an un-inked surface plate and you end up with little silver points of shiny metal where the Canode has been rubbed off. Now you can see exactly where the work is contacting the plate. I wanted to be able to show the whole bottom surface I was working on, but was having trouble trying to figure out a way to photograph the bottom of the vise showing all of the shiny spots at once. I had the best luck by lowering the ISO setting on my camera to 80 and only focusing of a small area of the vise. While lowering the ISO made the picture very dark, you can see some of the shiny spots that I see with my eyes. There are even more spots in the brighter area than the picture is showing, but this was the best picture out of a bunch that I took. The remainder of the bottom of the vise body looks similar to the small area I was able to photograph. In the least densely scraped areas, there are about 18 points per square inch. In the most dense area, where the ring of the vise base will make contact with the vise body, there are 20 to 30 per square inch. My scraping of the vise's bottom surface is a bit less even in points distribution than I'd like, but I am a bit out of practice. However, the surface is a whole lot better than when I started. As for the dark picture and my lack of photography prowess, many of the shiny spots didn't get captured by the camera. I'm not surprised by this, as when I am trying to see the shiny spots to scrape them, I have to constantly move my head around to catch the reflection of light from each spot. It's tough to get the camera to see what I see.

I scraped a few more passes after I took the pictures, then declared the bottom surface vise body bottom done. Time to move on to scraping the ring on the base.

Reverse spotting. In this picture, I was having trouble getting the camera to see the spots due to the glare on the scraped surface.
I switched the camera's ISO setting down to 80 which darkened the picture so you can see some of the light reflecting off the high points.

In the last article, when I had finished scraping the bottom of the  swivel base, I had measured the difference in height between the ring and the base at about a quarter thousandth - 0.00025" - higher on one side of the ring. This measurement was taken around the center of the half inch wide ring. When I re-measured the ring on both the inner and outer edges, I found that I had a difference of a half a thousandth. This is still a pretty small amount, but the goal was to get the ring as flat and parallel to the bottom of the swivel base as possible. I dabbed a few drops of red Canode on the vise body and rolled it out with a one inch diameter, six inch wide paint roller to get ready to mark the ring. Speaking of the paint roller, I use the ones that are sold to paint behind toilets and other tight areas. Before I use them for the first time, I roll them over duct tape to pull off any loose material. I have one for each color and type of spotting fluid and I keep them in plastic tubes when I am not using them. When they get contaminated with flecks of metal, I pick off what I can see, but eventually they start leaving the flecks on the surface I am covering with spotting ink. When this happens, I don't bother trying to cleaning them any further. I tried that once and the roller still left metal on the surface I was inking. Now I just replace the rollers when they get contaminated.

The vise body worked pretty well as a scraping master, but I would have preferred to use a granite plate if the center ring of the base didn't stick up above the surface I was trying to mark. I have a cast iron surface plate and a number of cast iron straight edges - with and without angled sides for marking dovetails. However, I like marking with granite better. It seems to hold the marking fluid better and you don't stand the chance of raising a burr on a granite surface. However, using the vise body to mark the base ring was the right tool for the job.

Before I marked the ring, I measured the height of the ring and made notes of the high areas, then did my marking print. I concentrated my scraping on the high side of the ring and re-measured its height after each pass. This was a little tough to do as the ball point of the DTI bounced around a bit due to the different depths of my scrape marks as I measured around the ring. I made a few more passes until the high points were close to the same height around the ring. Since there is a gap on the screw side of the vise body that I am using to mark the ring, one section of the ring did not get color on each spotting print. I decided that I would rotate the vise body a quarter turn for each new print so that after four scraping cycles, I had covered all sections three times.

With the vise body bottom scraped, it was time to use it as a scraping master to help me scrape the vise's base ring. After each scraping pass, the ring was height checked on the surface plate.
The total height of the ring was only out by half a thousandth, so it didn't take many passes to get color. The bottom of ring didn't get color due to the gap between the vise rails.

When the height was close to being even all the way around the ring, I took four spotting prints without scraping. I just cleaned off the previous ink, turned the vise 90 degrees and took another print. The prints were very close to looking the same for each of the four attempts, so it was time to start to refine the surface. I sharpened up a few blades for my scraper. I have a eight inch aluminum disk attached to a one horsepower motor that I use for honing the carbide blade tips. I use the outer race of a two inch diameter ball bearing attached to a handle to apply a mixture of oil and 1200 mesh diamond dust to the disk. I press the bearing into the disk and let it spin to embed the diamond dust. A couple passes of the scraper blade over the disk keeps a mirror finish on the blade tip. I then hone the flanks of the carbide tip on a plate of glass coated with more oil and diamond dust to get a nice crisp cutting edge.

Since a sharp blade cuts much nicer than even a slightly dull one, I used a newly sharpened blade to scrape around the ring once. After re-spotting the ring, I switched to another newly sharpened blade. This went on for about a dozen passes until the surface of the ring was only moving the needle of the DTI less than a ten-thousandth between individual scrape marks. There are a few divots where I dug the scraper in a little too deep, but the high points on the ring are now within 0.00015" all the way around.
Right or wrong, I have scraped this vise with only the smallest amount of difference between the height of the points to the valleys beside them. I felt there was no reason for oil pockets. When the vise does get moved, or the swivel feature is used, the slight wear that occurs won't come close to the wear that the ram dovetails see. Eventually the surfaces will wear, but by that time, it will be time to pass the shaper on to someone else.

I made one final scraping pass, then checked the ring height one more time. With the ring done, I started thinking about how I will even out the top surface of the vise rails. At the moment, I am leaning toward using the shaper to resurface the vise rails - provided that I can get the shaper to be as accurate as I need for this job. To get the rail top surfaces parallel to the table, I need to make sure that the ram and cutting bit runs parallel to the table. To get started on this, I needed to make sure that my measuring tools were still accurate after not being used for a while.

To check the ring height, I set the DTI at zero and measure the height of the ring all the way around. At this stage there's about 0.0003" difference between high and low areas.
For this picture, the height of the ring is within 0.00015" all of the way around. There are a couple scrapes that are deeper, but they won't affect the registration of the body on the ring.

My first job was to re-level my surface plate using my import box level. This level is graduated to 0.0002" per 10 inches of distance and is more sensitive than my hand scraped, shop made levels using Starrett 199 vials (0.0005" per foot resolution). The import level is a pretty nice tool for the money and the machining (grinding) is quite good. The two ground surfaces (bottom and one side) are as close to 90 degrees as I can measure on my "A" quality surface plate using my precision box and cylindrical squares. The only issue I have had with this level is the adjusting mechanism. It isn't a great design and I have had to add a flexure spring below the vial holder to keep the adjuster and vial holder from moving around if the level is bumped too hard.

Before I could level the surface plate, I needed to level the level - or at least adjust it so that it reads the same when swapped end for end. I do this by placing a strip of masking tape on the surface plate and marking the position of the level. I slide the level up against the tape and center it between my marks. The tape helps to allow me to repeat the level's position on the surface plate accurately. I note the position of the bubble after the level has sat at rest for a few minutes, then swap it end for end and note the new bubble position after the bubble settles. The level should read the same in either orientation. If not, turn the adjuster and lock it at half the difference between the two bubble positions. Repeat this until the bubble shows the same reading in both positions. The surface plate does not need to be level for this to work. I can usually get the level to read within a half of a division of true in about 15 - 20 minutes time. Most of the time spent is waiting for the bubble to stop moving.

Adjusting the box level. It's a little tricky to do because the adjustment changes when you lock the second nut.
Using tape with marks to allow me to repeat level placement accurately, I swapped the level end for end as I made adjustments. The level is zeroed.

I level the surface plate diagonally by using two tape stripes placed corner to corner with gaps in the center. Again, the tape helps me to position the level in the same spot each time as I adjust the feet on the surface plate's stand. Once the surface plate was level, I could now check my double-sided straight edges and parallels for level as well as checking them for height with a DTI. With my measuring tools checked, it was time to try to level the shaper again. I had run into some problems the first time I had tried to level it. The table seemed to slope down toward the front of the machine by about 0.0015" over the 12" table in comparison with the left side casting that holds the dovetails for the ram. One or the other is out and it and I assumed that it was the table. I figured that the large boss was machined in the same setup as the dovetail ways that support the ram and should be parallel to the dovetail ways. The next issue is that the my level shows that the cross rail is not flat, nor is it sloped in only one direction. I get one reading on the left, another on the right and a third in the center. This reading is different than the reading I get from setting the level on the top of the saddle. To make matters more interesting, the casting that the table support sits atop gives another reading. The question I have is which one, if any, are accurate and what reference surfaces do I use to level the shaper? While it is possible to check for square and parallel without leveling the shaper, having the a level machine tool makes checking it much easier for me.

The surface plate is now level and I can check my double-sided straight edges for being parallel with both a DTI and a level.
A very short pivot test with the straight edge confirms that the top of the cross rail casting is a bit concave. The ways appear to be straight.

During my level checks on the shaper, I removed the table. I found a rather large burr along the top edge of the table that mates with the front of the saddle. I doubt that this burr was enough to account for the difference in level I was seeing between the table and the ram casting, but I stoned it flat to give the table a better chance of mating correctly. I also lightly stoned all the surfaces I would be putting my level on. 

To check why I was getting different readings as I moved the level across the cross rail, I got out my old Stanley cast iron carpenter's level that I had scraped both top and bottom surfaces flat and parallel as my third scraping project almost a decade ago. I checked it on my surface plate and it still is flat within a couple tenths over its 24", though being so thin, it needs to sit untouched for a while to stabilize after receiving the heat from my hands as I move it around. One of these days, I will add some wood blocks to it so I don't heed to touch the cast iron. Since the level/straight edge is only an inch wide, it was the perfect width to sit atop the cross rail and not hit the ball oilers at either end. I tried a pivot test on top of the cross rail and found that the straight edge wanted to rotate around each end. This indicates that the cross rail is concave. However, the dovetail ways on the cross rail seem to be straight.

If I place the box level on the saddle, I can run the saddle all of the way from the left extreme to the right and the bubble remains in the same position, within one division. This is leading me to the conclusion that the dovetails of the cross rail are true, but the top of the cross rail is not. The last check was on the machined casting at the front of the shaper that the table support rides on. It is obviously worn. There is some surface damage where swarf had gotten under the support and wore lines in the casting. The casting is high on the left side by about 0.002" per 10" according to my Moore and Wright level which has a resolution of 0.0036" per 10". About a half division out. This isn't a huge amount, but if you were taking a cut with the feed running right to left with the support in place, it would try to raise the table two thousandths for each 10". The spec for this in the Sheldon manual is one thousandth per nine inches, so it is about twice the allowable limit. At this point, I am thinking that I need to scrape this part of the casting to be parallel with the saddle top, then scrape the bottom of the table support flat. This may change as I still need to check the ram in both the X and Y axis. Hopefully the X axis of the bottom of the ram's dovetail ways will match up with the top of the saddle. If not, I have a larger project ahead of me.

Note: I am naming the axes as you would for a vertical miller, which may or may not be correct. I haven't found a source that defines it. The Z axis is the generally the axis with the rotating tool. Since the tool bit in a shaper is situated vertically - although not rotating - and I am used to thinking in terms of vertical millers, I chose this naming:  X - left right, Y - forward back, Z - up down.

The saddle runs true across the length of the cross rail dovetails. There was less than one division (0.0002") variance.
The boss that the table support rides on is not in the same plane as the saddle and is visibly worn. It will need to be scraped.

I clamped my thin straight edge to the bottom of the ram ways. I then set up the DTI on a magnetic base on top of the saddle. I ran the saddle as far as I could on each side of the clamp and read how parallel my extension of the bottom of the ram ways was to the top of the saddle. The top surface of the saddle was parallel with the straight edge within two tenths per 10" inches. The Sheldon spec measurement is taken with the DTI attached to the tool head and with the finger riding on the top of the saddle. Sheldon says that the maximum deviation should be no more than one thousandth per nine inches. We're well within that spec. My reason for using the straight edge attached to the bottom of the dovetails was to extend the bottom plane of the ram ways and compare it to the top of the saddle. I needed to try and figure out what references I have that can be used to level the machine. I am now beginning to get an idea. With my new information, I would now level the table to be in the same plane (X axis) as the top of the saddle.

When I had the table off, I noticed some scraping on the mating surfaces of where the table attaches to the front of the saddle. I don't know when this was done, but the scraping is pretty sparse. It looks like maybe one or two quick cycles. It appears that someone just scraped down the high areas and left the remainder of the mating surfaces untouched. I have no way of knowing whether this was done at the factory or a later attempt to align the table. I did put a straight edge to the table rear surface and the front face of the saddle that it attaches to. It showed both surfaces to have no obvious high areas. I will not ink them up and check contact unless I have a problem with aligning the table. I reinstalled the table to the saddle using my engine hoist. The table is not all that heavy, but the three bolts that secure the table are captured in a circular T slot and are free to move. Trying to hold the table and line up these bolts would take more hands than I have. Even with using the engine hoist, it was a bit of a juggling act.

Using the straight edge to allow me to test the planes of the bottom of the ram dovetail ways and the saddle top for being parallel.
I measured the deviation from parallel on both sides of the ram and found it to be quite close to parallel. It's about 0.0002" per 10" out.

The next check was to see if the Y axis of the table (front to rear) was in the same plane as the ram travel. I removed the tool head, attached the magnetic base and set the DTI to read the table. I set the ram travel at its maximum of about 13.5" of travel and ran the ram and DTI across the table by spinning the Reeves pulley manually. I read 0.00025" over the 12" table. The spec is 0.001" in 12". While this is very good, it has me scratching my head. From my readings, the ram and table are pretty much in the same plane, but the machined casting that holds the dovetails is in a different plane by almost 0.002". One would think that the top of the casting was machined on the same setup that was used to machine the dovetails and they should be true to each other. The next check will be to check and adjust the ram gib. If the gib is loose, it could allow the front end of the ram to droop as it extends from the shaper. If the table was resurfaced while the ram was loose, it could explain why the ram and machined casting don't match.

Putting the table back on so I can check the front to rear level. The casting is not that heavy, but getting the bolts lined up takes 3 hands.
The DTI is set at the rear of the table and the ram stroke has been set to the maximum. The table was previously lightly stoned.

I have been thinking about how Sheldon might have machined this shaper for the past few weeks and can't reconcile what I've measured to how I think the shaper was built. I will preface my thoughts with the fact that I don't have a lot of experience analyzing and rebuilding machine tools. I will also say that I enjoy the thought process of trying to figure out the reasons that I am seeing the lack of parallelism between parts, but I am a bit frustrated that the measurements don't make sense to me. If you enlarge the picture above left, You will see the machined boss I am referring to. It is machined on its top side, as well as the side facing the camera. Inboard of the camera facing side, it is machined again on the top side ( a couple inches lower) to support the bottom of the dovetailed ram and also at an angle to mate with the angled side of the ram dovetail. It runs from the rear of the shaper to the front and is visibly parallel to the ram dovetail that is extended about 4" past the dovetailed ways that hold the cross rail. This machined area ends at the intersection of the front face of the dovetails that the cross rail slides vertically on. My assumption is that this horizontally machined area should be square with the front face of the cross rail dovetails and that it should also be in the same plane as the ram dovetails. I have measured the lack of parallelism between the machined casting and the ram to be around 0.0015" per 10". I can only think of four reasons why the left side ram casting is not in the same plane as the ram.

1. I am measuring using too sensitive a level. I could almost accept this, as the Sheldon specs are in the realm of 0.001" per 9" for the saddle to ram specs, or for the side of the table to the ram plane, 0.002" per 12". However, as you will read later, the deviation I am seeing between the machined area and the ram is 10 times worse than for the accuracy of the saddle sliding across the cross rail ways and the ram and table being parallel. In other words, the rest of the machine is substantially more accurate than the Sheldon allowable limits except for this one area.

2. The ram dovetail was machined in a separate setup than the top boss and the front face of the casting (which are square with each other). If the dovetails were machined in a separate setup, I could see some miss-match of the planes happening. However, most machines I have dealt with or read about have a reference boss in the same plane as the dovetails (machined in the same setup) so that they can be brought back to true after they wear. I would think that this boss is the most likely candidate for a reference. 

3. The front of the dovetails have worn on the ram and body casting and the ram has dropped a bit in front.  If this was the case, I would think that this would mean that some previous owner had used the shaper to resurface its own table after the ram had dropped. I suppose I could check for this if I remove the ram. I would prefer not to have to do this.  -- After I adjusted the ram gib, the ram became more parallel with the table, so this idea probably isn't the problem.

4. The machine tool that machined the shaper body was out of adjustment or worn when this shaper body casting was machined. By my measurements, the boss plane and the ram plane are different by a few thousandths over the length of the ram and boss. On an industrial machine tool of the size and rigidity necessary to machine this fairly heavy casting, I would expect closer tolerances.

Enough speculation. Tomorrow I will check the adjustment of the ram gib. Depending on what I find, I may be OK or I may end up having to pull the ram and scrape the ram dovetails.

The DTI shows 0.00025" over 12". Not as good as I'd like, but not too bad at all. The table is not in the same plane as the left side ram casting, but is close to parallel with the ram plane.
Since the machined casting on the opposite side of the ram isn't level with the table, I will check the adjustment of the ram gib. Chalk marks show the slotted gib adjuster screw positions.

To check the gib adjustment, I set the DTI up to read the side to side movement of the ram and zeroed the needle. I pushed on the ram with my full body weight. It takes a few moments of constant pressure to squeeze out the oil film between the dovetails. When the DTI's needle stopped moving, I noted the reading. I then reversed the direction by pulling on the ram. Total movement was about 0.002".  I don't have any specs for the ram dovetail clearance, but around one thousandth of an inch total clearance is normal for milling machine table ways I've dealt with and this was what I was going to use. I removed the aluminum scale from the top of the gib side casting, loosened the top bolts that held the long gib in place, then undid the lock nuts on the four adjusting screws. I turned the screws in tight, the center two first,  until the ram was hard to move by spinning the Reeves drive pulley by hand. I backed them off a fraction and cinched down the top bolts. This caused the ram to lock up due to locking bolts pinching the ram gib against the dovetail. It took a couple more tries until I had reduced the side to side play to 0.001". I re-ran the test of checking the parallelism between the ram and table. The amount the ram was off being parallel with the table was now down to about 0.0001" along the 12" table, with the front of the table being lower than the rear. This is an order of magnitude better than the Sheldon spec limit of 0.001" in 12" and better than my previous measurement of 0.00025". 

Perhaps I will never know the reason for the boss along the left side dovetails not being parallel with the ram. At this point, it doesn't really matter. The ram and table are in the same plane and the X axis is square with the ram stroke. I suppose that I could scrape the boss to be co-planar with the ram and saddle top, but since I now know that the table is true to the ram and the saddle, I am satisfied that I can level the shaper by the table. I had considered planing the table before, but there is no reason to do this when I am only measuring one ten-thousandth difference over the length of the 12" table. I will still scrape the machined portion of the casting that the table support rides upon so that it is true with the side to side saddle axis and get on with machining the vise rails. Getting the table support flat and true should help the shaper make parts that are square with themselves.

With the DTI set to measure side to side movement of the ram, I pushed on the ram to squeeze out any oil film. Reading of - 0.001"
I now pulled on the ram long enough to displace  the way oil in the other direction. This time the reading was + 0.001". Total of 0.002" movement.

That's it for this installment. The next steps are to work on the tool head and to scrape the table support pieces.

Shaper 1
Shaper 2
Shaper 3
Shaper 4
Shaper 5
Shaper 6
Shaper 7
Shaper 8
Shaper 9

© Fager August 17, 2015