48” Featherweight Camelback Straightedge Pattern is Taking Shape. - Page 3
Close
Login to Your Account
Page 3 of 4 FirstFirst 1234 LastLast
Results 41 to 60 of 71
  1. #41
    Join Date
    Jul 2005
    Location
    Cottage Grove, MN 55016
    Posts
    7,597
    Post Thanks / Like
    Likes (Given)
    4095
    Likes (Received)
    4540

    Default

    He's has done it in my threads I started, so he now knows what it feels like :-)
    You don't think what he is doing this thread and showing his Ebay ad isn't self promotion? Sort of like politics, one does it and he gets all the bad press and the other party does it and no one says a word. Have a nice day.

  2. #42
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    My suggestion is for anyone wishing to address this “behavior” rather than muddy up a thread that has been intended to be informative and perhaps even interesting, that they start a separate thread where the usual accusations and criticisms can be made (to no avail) and everyone can have their say. One frequent participant in such debates was kind enough to remove his post from this thread last night for example. I am not encouraging such a thread by the way since there really can be no reasonable expectation of any resolution. You guys choice...

    Denis

  3. Likes neilho, Hodge liked this post
  4. #43
    Join Date
    Apr 2014
    Location
    Austin,TX
    Posts
    286
    Post Thanks / Like
    Likes (Given)
    19
    Likes (Received)
    106

    Default

    Quote Originally Posted by Richard King View Post
    If anyone needs a 48" Camelback Straight Edge now I have them in stock. Model HK-48, 44 pounds, 47 3/4 L x 2 1/4 W x 9" H. Photo of my patterns Attachment 263895
    Although I hate to interrupt this great thread, I have to ask...whats the deal with the Chinese writing on the King Way?

  5. #44
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    I have spent the last couple days builidng larger flasks to fit the larger pattern to make the needed casting molds and doing finish work on the pattern. A detailed pattern like this one has to be finished meticulously or it will not pull from the sand cleanly.

    I have spent some time filleting the inside corners of the pattern. There are 80 intersection of three planes (the corners) and 80 intersections of 2 planes. Getting a nice clean fillet in the 3-plane corners is very tricky. But, I've been trying with pretty good success a, so far as I know, new technique of using a bead of viscous epoxy glue laid into the inersections of both two and three planes. The surface tension of the glue and its natural "wetting" tendency makes pull itself into very nice fillet in about 1/20th the the time it would take to place a conventional filler like Bondo into the intersection and then shape ti with a pattern maker's ball and then sand, refill, and repeat til there is a good fillet. I've always used that general method with various paste fillers and it has always been a major time sink as well as being mind-numbingly boring. I'm pretty excited about this method and will be reporting it at a pattern making/casting forum I frequent. (Yes, I have tried fillet leather, wood cove sticks, wax, caulking compounds, etc and I have not found any of them to be satisfactory for the style of pattern and its eventual use in green sand)



    So, it looks like the filleting will take far less time than usual. I will want to see how it looks in an actual cast piece before I count it as a success, however.

    Building flasks is pretty straightforward, but there are special considerations for handling equipment that I fabricated in my molding room that allows me to singlehand the 450 pound flasks/molds. I make my flasks out of 2X6 or 2X4 lumber and then attach heavy metal pins and flanges to the flask ends that allow lifting and flipping the flasks over using a chain hoist as part of the mold making process. I will make a video of that when we get to that stage----hopefully by mid week next week. The way things are going that should be doable.

    Denis

  6. Likes lucky7, neilho, TGTool, Bartolo liked this post
  7. #45
    Join Date
    Oct 2009
    Location
    Oregon
    Posts
    4,183
    Post Thanks / Like
    Likes (Given)
    4487
    Likes (Received)
    2123

    Default

    Quote Originally Posted by dgfoster View Post
    Sure, it is pretty common to use aluminum for a working pattern. And if I were sending my work out, I would have to use a metal pattern as foundries are not known for their gentle handling of patterns. I have seen first hand the results of a guy “ gettin er done.” My patterns were chipped, broken, threaded plugs pulled out etc.

    But, I handle my patterns pretty carefully and they have suffered no ill effects of use. So ,for now, I am ok with the Baltic birch and lacquer patterns. The lacquer is pretty hard and has been applied in multiple coats which makes them tougher. And the Baltic birch plywood itself is quite strong.

    I appreciate the suggestion and it is not an idea that is off the table.

    Actually, I’ve been daydreaming about the next pattern. Seeing JST’s thread and people talking about a 30 with a prism base has me musing about a pattern for such made with a cored-out base. That would mean you could have such an SE with a prism base but it could weigh a lot less than one with a (far simpler to mold and cast) solid but back-breaking base. Just thinking...

    Denis
    If you get your basic design fingered out it'd be probably be a couple hours of cad/cam and a couple different tapered endmills to mill the entire thing from solid 6061. Especially if both sides are same/same. Cast iron patterns skip the whole shrink calculation and voodoo steps.

  8. #46
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Quote Originally Posted by Garwood View Post
    If you get your basic design fingered out it'd be probably be a couple hours of cad/cam and a couple different tapered endmills to mill the entire thing from solid 6061. Especially if both sides are same/same. Cast iron patterns skip the whole shrink calculation and voodoo steps.
    Interesting idea. What do you suppose the cost of a block of 6061, appropriate end mills, CAD and machine time might be? BTW the front and back of the pattern are not the same as the bow is centered to the "rear" of the sole in such a way that there is about 2 inches of sole on the front half and 1 inch on the rear. Also the ribs are considerably differently shaped so that the SE can reach more than an inch under an overhanging v-way.

    Another consideration for me is pattern weight. It is necessary to pull the pattern very precisely form the sand lest the sand print be damaged. The wood pattern weighs only about 4 pounds and 2 pounds front and rear. A comparable iron set would be 22 pounds and 11 pounds. Aluminum would be on the order of 7.5 pounds front and 3.8 pounds rear. Finessing a 22 pound pattern might be challenging. 7.5 pounds probably would take some getting used-to, but probably could work. The lettering could be machined I am sure with smaller end mills but could also be glued on.

    Denis

  9. #47
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Today's shop time was spent mostly making flasks to accomodate the new patterns. The inside length is 54" and width 13" with the drag being 4.5" deep and the cope 3.5". I started out making them from 2 X material with end plates to attach studs that allow lifting and turning the flasks and also allow binding them together. I had intended to just weld 1/8 x 1" bars one foot long to the end plates and attach the bars with screws to secure the plates to the flasks. But after I got to looking at that setup, I thought I could get both side-to-side stiffening of the flask sides (desirable) and greater tensile strength (not really needed) but nice if I extended the bars full length and screwed them down full length. The increase in lateral strength is impressive. (Works like a steel-wood flitch beam.) This stiffness was a concern because of the weight and length of the flasks and mold. The mold will weigh about 450 pounds. If the sides flex some as the flsk is rotated, there is a big risk of sand dropping out. I think (and hope) this system will be rigid enough to avoid such problems. Am I posting this because I think this is an ideal solution to the problem? No, not at all. Just reporting on what I am doing FWIW. We'll see how it works.

    I made a set of steel flasks quite some time ago for the 36 straight edge. They are wonderfully durable, but they are pretty heavy weighing about 85 pounds total. This wood/steel composite flask is about 1/2 that weight. And the steel flasks were somewhat expensive and time consuming to make. If this pattern is a winner and I burn up the current flask, I may then make steel flasks for it. (Wood flasks are very easily burned up if there is even a small spill of molten iron.)

    Tomorrow I will finish up the cope and start painting the pattern tonight. Paint always reveals the defects in the pattern that will require filling and sanding, filling and sanding........

    pattern-making-27-.jpg

    pattern-making-28-.jpg

    pattern-making-29-.jpg

    pattern-making-25-.jpg


    Denis

  10. Likes TGTool, Demon73, Hodge liked this post
  11. #48
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    The pattern is ready to ram up in green sand. Hopefully, that can happen tomorrow and if the weather is reasonable I can do a trial pour. I don’t expect the first (few) pour(s) to result in a usable casting. There are a lot of variables concerning runners, gating, risers etc the will need to be worked out. The first pour could be great if I am incredibly lucky. Regardless I am eager to try.

    (Incidentally, work is soon to begin on yet another pattern. This one will be a lightweight master square 12 x 30 x 4” that should weigh around 60 pounds. I don’t think there is anything equivalent available new or used. You will be hearing more about that later. That design will be even more challenging to cast, but, if I can get er done, I have a preorder already as the design is by request.)

    Here are a few pics:
    pattern-making-33-.jpg


    pattern-making-30-.jpg






    Lettering is glued to aluminum strips 1/4" wide by 20ga. This allows for more accurate placement and better adhesion. The strips are "let into" the pattern wood so they sit more or less flush. I do not paint over the letters as the surface tension of the liquid paint tends to soften outline the letters making them look unsharp when cast.

    pattern-making-32-.jpg


    At each end of the split pattern is a 3/16” pin and corresponding alignment hole.

    pattern-making-31-.jpg


    Denis

  12. #49
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Here is the runner pattern I will try with this SE pattern. It is similar to the one I used with the 36. But, that does not necessarily mean it will work for this pattern. BTW, it looks like this casting will be 37 pounds as cast----I intentionally left a little more meat in the sole to be milled or planed off later. That is a little "cheap" insurance against some minor surface defect ruining the usefulness of the casting. Machined it should weigh about 33 to 27 pounds depending on the user's preference. The runner pattern is made from 1/4" Baltic birch ply..
    pattern-making.jpg


    Denis

  13. Likes ballen liked this post
  14. #50
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Just a brief note but, for me, an important one. I was able to ram up and cleanly pull the 48"pattern today. Whew---it took every bit of concentration and care I could muster. I was worried I might have missed getting enough draft into and area or that I might not be able to pick the pattern out of the sand without bumbling somehow and damaging the mold. But it worked! True, the cope half FELL OUT of the cope when I was moving the cope latterally on the barn door track that my chain hoist traverses on. Maybe that was due to applying graphite to the entire cope half of the pattern or maybe it was just the slight vibration of the moving on the overhead trolly. In any event, I was less generous with the graphite on attempt #2 and flipped the cope right way and then traversed rather than traverse with it level in the same orientation it had when I lifted it off the drag.

    Tomorrow I will try to fill it with iron. That may be another story!

    Denis

  15. Likes ballen liked this post
  16. #51
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default Well, partial success ;-)

    I did do a trial pour of the pattern on Wednesday. There is good news and some bad news as well.

    The good news is that the runner system seems to work well and the mold filled fully(until it leaked). That is very encouraging as getting a complex mold to fill completely can be challenging. On the 36" Featherweight I went through quite a few iterations of runners and gates prior to getting it to fill reliably. The surface finish on the casting looked great and the detail rendition on the lettering was excellent.

    Now the not-so-good news: I am kind of embarrassed that I forgot to put the mid-clamps securing the center portion of cope to the drag on. I blame this rookie oversight on having visitors at my foundry. (I love having visitors, mind you, but on a pattern there is a lot to think about and remember. Explaining everything as you go can be a bit distracting just like it is when working at a machine etc.) Since this is a long and relatively shallow mold and since I use wedges under the drag at each end to get the mold level, the drag predictably must have sagged a bit under the weight of the sand. This resulted in a very thin gap or near gap between the cope and drag. Then, when I added molten iron, the head pressure must have wedged the two parts apart allowing a 1/32 gap. That is plenty for molten iron to insinuate itself and as the iron enters is adds to the horizintal surface area of molten metal which further increases float pressure. At that point the die is cast (so to speak) and, to the caster's frustration, you see a stream of molten iron cascading out of the mold. At that point there is no way to fill the mold or stop the leak, try as you might.

    Lesson RElearned! I have not had a breakout like that in 18 months. Super frustrating as a lot of work and a weather opportunity goes down the drain. Oh well, I'll give it another go next week. It's just part the game.

    a couple of pics---might as well share the misery:

    pattern-making-34-.jpg


    pattern-making-35-.jpg


    You can easily see all the fins especially in the center four bays of the casting. You can also see that that each end of the casting looks pretty normal---that is b ecause the fatal sagging happened in the middle of the mold, but the ends were held together by clamps that hold the ends together. One interesting thing I noticed is that I pulled this failed casting from the sand while it was still red hot and it cooled pretty quickly in the open air. Every once in a while I heard a pretty sharp TINK. And then a chunk of fin fell from the casting. The explanation was that the thin fins cooled really fast and contracted quite a bit whereas the main part of the casting cooled a bit slower. So much tension developed between the fina dn casting that the metal fractured.

    I will use my calibrated Wilson Hardness Tester to see how much hardness developed in the casting because of this rapid cooling. I usually let the casting cool at least 6 to 8 hours in the sand so that the casting is down to 400 or 500 degrees before opening the mold to avoid hardening.

    One other note: The casting weighed 34 pounds as miscast and, when corectly cast, should hit the target of 37 pounds very closely. that means it will machine to 27 to 34 pounds depending on the owner's needs.

    Denis

  17. #52
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Yahoo! On the second try (after the initial failure reported above) it poured nearly perfectly. I am surprised actually and very very happy!

    The casting weighs just a few ounces shy of 50 pounds as it is with blind risers, runners, and pouring basin.

    There are a couple of minor contraction defects in the front of the sole at the fourth rib from the left. I am pondering why this happened.
    It will machine out and is of no consequence, but I wish I could explain it better.

    No pics, but sighting down the sole from the end shows it only bows up about a 1`/16th of an inch over its length as I made the sole with a slight downward
    bow to prevent more bowing based on my 36" design casting characteristics.
    img_6007.jpg


    img_6010.jpg


    Letters and finish
    img_6009.jpg
    img_6012.jpg




    I will tweaking my handling equipment a bit and making a couple improvements to my molding flasks prior to the next pour of this 48.

    Today I will trim off the gates, runners, and and blind risers and see what the raw casting weighs. It should machine down to about the low 30's to mid 25 pound range depending on the user's desires.

    Denis

    Edit: I just reattached photos so they show. Evidently, they were not visible to others as I first embedded them even though they looked fine from my browser. Go figure.
    Attached Thumbnails Attached Thumbnails img_6008.jpg  
    Last edited by dgfoster; 09-21-2019 at 05:13 PM.

  18. Likes Paolo_MD, M.B. Naegle, mattthemuppet liked this post
  19. #53
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,082
    Post Thanks / Like
    Likes (Given)
    4320
    Likes (Received)
    1838

    Default

    Denis, the four images you linked from thehomefoundry.org aren't showing up. When I cut the link URL and try opening it directly, I get a "You must be logged in to do that." error from The Home Foundry. I located your thread over on that forum, and when I click on the thumbnails there, get the same message as I'm not a forum member over there.

  20. #54
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Quote Originally Posted by sfriedberg View Post
    Denis, the four images you linked from thehomefoundry.org aren't showing up. When I cut the link URL and try opening it directly, I get a "You must be logged in to do that." error from The Home Foundry. I located your thread over on that forum, and when I click on the thumbnails there, get the same message as I'm not a forum member over there.
    Thanks for letting me know, sfriedberg. I re-embedded the photos which should be fine now----I hope!

    I did cut off the gates and risers this morning and the casting weighs just a few ounces less than 40 pounds. It should machine nicely to the low 30's and less if so desired.

    Denis

  21. #55
    Join Date
    Oct 2010
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    5,082
    Post Thanks / Like
    Likes (Given)
    4320
    Likes (Received)
    1838

    Default

    Quote Originally Posted by dgfoster View Post
    I re-embedded the photos which should be fine now
    Looks good!

  22. #56
    Join Date
    Sep 2008
    Location
    Canada
    Posts
    941
    Post Thanks / Like
    Likes (Given)
    373
    Likes (Received)
    350

    Default

    Great work!

    One question from someone who's never done pattern work: do you have enough of a resevoir/mass of iron at the ends to avoid chilling? Bigger gates at ends? A Canadian pattern maker selling iron right angle castings has had this problem mainly with end angles 60deg and more acute which your pattern does not have.

    Best regards,
    Stan.

  23. #57
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Quote Originally Posted by lucky7 View Post
    Great work!

    One question from someone who's never done pattern work: do you have enough of a resevoir/mass of iron at the ends to avoid chilling? Bigger gates at ends? A Canadian pattern maker selling iron right angle castings has had this problem mainly with end angles 60deg and more acute which your pattern does not have.

    Best regards,
    Stan.
    That is a good question, Stan. The answer is I test the hardness of each SE I cast and have found that they are consistently soft including this new 48" casting. This one tests Rc12 at its extreme ends---the area where cooling occurs most rapidly. For those not conversant in Rc numbers, that is the same as 1018 ("mild" ) low carbon steel. It doesn't get much softer than that.

    As you might guess, there is more to producing a quality casting than filling a hole in the sand with recycled manhole covers and broken drain pipe.

    I start by purchasing all of my metal as grey iron returns from a regional commercial foundry that supplies local refineries, aluminum smelters and the like. They have to meet stringent requirements and test all of their pours with a sophisticated spectrometer. So, I know what I am melting and that is a good start. I,then, am careful about maintaining a proper reducing atmosphere throughout the melt ---another important factor in avoiding upsetting the desired alloying mix of the iron as it is melted. The next step is to add ferrosilicon at the proper time and in the proper amount just prior to pouring the metal. Add it more than 5 mins prior to pouring and its effect on preventing chill and improving fluidity of the metal is lost. Next, I am careful to allow the casting to cool properly before shakeout (or in my case "dig out:" since the mold at 350 pounds is too big for me to shake!) the casting---at least 4 hours for this size casting. And the last step that is done on every straight edge is hardness testing with a calibrated Wilson Hardness Tester. (I know of no other foundry that routinely tests their castings for hardness). Prior to machining or shipping a raw casting, each one is thermally stress-relieved following standard high-temperature protocols.

    Above and beyond all that testing and care, the rubber meets the road when you machine the castings prior to scraping them. An experience machinist can tell if the metal is soft and is cutting easily or it there are hard spots (I have heard of castings where there were spots so hard as to ruin carbide tooling!) that are cutting with excessive resistance. I have machined many many of the 36" and 18" straight edges prior to shipping them off to end users. I have yet to encounter and evidence of a non-uniformly soft SE.

    In summary, I do everything possible to ensure I am producing a superb SE that will be a pleasure to scrape, is stable, easy to lift, and comfortable to use. I take that very seriously as my reputation as a caster depends on providing excellent castings.

    Teaser: (I have completed 1/2 of the work on a pattern for a lightweight 12" x 30 x 4" four-sided master square projected to weigh less than 60 pounds. I may have one cast within a month or so---hopefully sooner. That one will be a test of casting technique!)

    Denis

  24. Likes lucky7, sfriedberg liked this post
  25. #58
    Join Date
    Sep 2008
    Location
    Canada
    Posts
    941
    Post Thanks / Like
    Likes (Given)
    373
    Likes (Received)
    350

    Default

    Doubt I'll ever have a project that needs a master square that big but would like to see details and pics as the project proceeds. Will it have a pad for a level?

    L7

  26. #59
    Join Date
    Jun 2008
    Location
    Bellingham, WA
    Posts
    3,969
    Post Thanks / Like
    Likes (Given)
    948
    Likes (Received)
    2129

    Default

    Quote Originally Posted by lucky7 View Post
    Doubt I'll ever have a project that needs a master square that big but would like to see details and pics as the project proceeds. Will it have a pad for a level?

    L7
    I am making it on request from a long-established CNC tombstone and subplate maker who bought one of my 36" SE's and liked the general design. His shop had dropped their $10K ceramic square causing it to shatter. Not a good day. The shop wanted something one person could lift as they are currently using a granite square which was good for accuracy but required a crane to move it. Evidently, they and other shops also need a "travel" master square that could be checked as airline luggage. To his knowledge such a lightweight (Featherweight ;-) ) master does not exist. So, he requested I design and cast such a square. I promised I would give it a try and promised to buy one if successful. He gave me free-range on the design so long as it was of the general dimension stated and somewhere in that weight range. (I thought Christmas came early!) I guess I should start a thread on that process as well.

    Yes, it will easily accept a Geier and Bluhm precision vial on the inside of any of the reference surfaces, but I will provide a couple of pads on the castings to make that mounting even easier. One pad will be on the long leg and one on the short so it could be used with a level either vertically or horizontally. Likely a user would install two vials to allow convenient vertical and horizontal level use..

    It will be designed to accept a vial like the one shown below. this is the same vial that fits into my 18" Str Edge/Prism/Level/Parallel.

    geier-bluhm.jpg



    Denis
    Last edited by dgfoster; 09-23-2019 at 02:26 PM.

  27. #60
    Join Date
    Sep 2002
    Location
    Lawrenceville GA USA
    Posts
    6,211
    Post Thanks / Like
    Likes (Given)
    758
    Likes (Received)
    1336

    Default

    This has been a lot of work, thanks for sharing.

    Charles


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •