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  1. #1
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    Default Source for a dovetail scraping reference?

    I did a modest amount of scraping 20+ years ago to true up a small Chinese bandsaw. Scraping, hacksaw and files were my only option at the time. While not economic, the skill was worth the time spent. And the saw cuts true and will slice dime thickness pieces from bar stock.

    For lack of practice, I have done a number of projects recently using files rather than my milling machine just to maintain the ability to use a file.

    I bought a small lathe which I would like to scrape true and tune for precision work. Amazingly a 0.0001" indicator on the inside of the spindle taper does not move at slow speed. It increases a good bit when I speed it up, but I plan to address the imbalance by building a dynamic balancer and balancing the spindle plate. My assumption is that for precision work I'll use fixture plates or collets.

    To scrape the dovetails I need a spotting reference. Is there an economical source for these or do I need to make my own?

    If I need to make my own, what's the best material? I've got some ductile iron bar I can slice a slab off. That seems as if it would be the most stable material.

    This is a warm up exercise for overhauling my Clausing lathe.

    BTW I have a copy of Connelly. I've not read it in many years. But I did read it long ago.

    Thanks,
    Reg
    Last edited by CBlair; 04-29-2019 at 07:44 PM.

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    Reg,

    Your best bet would be to buy a piece of "dura-bar" and make whatever spotting tool you'll need. Especially on small machine like that, you want your spotters just the right size, any bigger and it becomes difficult to work with. You'll want gray iron for the straightedges/prisms, dura-bar is just the kleenex/band-aid/etc of the gray iron game. Mcmaster sells its gray iron as "easy to machine" and their ductile as "impact resistant, take a look at their short discs section, best bang for your buck iv'e seen on the net, put that bandsaw to good use! Alro also stocks gray iron, class 30 I believe, available on their online store, often available as drop/remnants that you can get a good deal on.

    Not sure how ductile iron is in terms of dimensional stability, but scraping it is more difficult compared to gray iron,scrapes much like steel.

    Corey

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    Reg, I have a couple 18-24” scraping masters , I am willing to let one go, it should probably be touched up but definitely easier than making your own . PM me and I will dig out take measurements and send you some pictures .


    Ray


    Sent from my iPad using Tapatalk

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    Quote Originally Posted by rhb View Post
    I did a modest amount of scraping 20+ years ago to true up a small Chinese bandsaw. Scraping, hacksaw and files were my only option at the time. While not economic, the skill was worth the time spent. And the saw cuts true and will slice dime thickness pieces from bar stock.

    For lack of practice, I have done a number of projects recently using files rather than my milling machine just to maintain the ability to use a file.

    I bought a small lathe which I would like to scrape true and tune for precision work. Amazingly a 0.0001" indicator on the inside of the spindle taper does not move at slow speed. It increases a good bit when I speed it up, but I plan to address the imbalance by building a dynamic balancer and balancing the spindle plate. My assumption is that for precision work I'll use fixture plates or collets.

    To scrape the dovetails I need a spotting reference. Is there an economical source for these or do I need to make my own?

    If I need to make my own, what's the best material? I've got some ductile iron bar I can slice a slab off. That seems as if it would be the most stable material.

    This is a warm up exercise for overhauling my Clausing lathe.

    BTW I have a copy of Connelly. I've not read it in many years. But I did read it long ago.

    Thanks,
    Reg
    This guy makes reasonably priced small castings for Straight edges and squares

    Martin Model & Pattern - your online source for fine quality patterns and castings

    dee
    ;-D

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    In addition to what folks have already said, PM member 'other brother' has been selling off his collection of scraping tooling. Includes cast iron masters.

    L7

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    Thanks to all. I couldn't find any castings for metrology items on Martin's website, but I'll email him.

    I'd like to have some small spotting tools for the mini-lathe, however, I want larger tools for my larger machines. I'll be in touch by PM. I'll also take a scraper to my ductile iron bar and see what that's like. Scraping steel is tedious at best.

    I'm trying to buy a copy of the publications by Moore Tool, but am having trouble reaching anyone. There are used copies of "Foundations of Mechanical Accuracy" on Amazon for $5000! Totally crazy. I had it once on interlibrary loan, but could never find a copy for sale. I very much hope that it is actually available from Moore.

    With the forum moderator's indulgence I'd like to explain what I'm up to.

    A small Schaublin or Hardinge toolroom lathe is either expensive or in need of a lot of work. And replacement parts are expensive and difficult to get. Chinese mini-lathes are partially machined casting kits for toolroom purposes. But parts are easy to get at reasonable prices. So if I make a mistake, it's not expensive. And I'll learn a lot more than buying a brand name toolroom lathe in good condition.

    The big question I have at the moment is the spindle bearings. While I read less than 0.0001" TIR rotating it slowly, I have no idea if the bearing preload is correct. You can often make a poor bearing look good for a while by excessive preload. But it galls quickly. My Clausing lathe is a plain journal bearing. Those are pretty easy to understand and adjust. Ball and taper bearings are rather more involved. However, I have tooling to make any adjustment called for whether end play per air cooled VW practice or rotational drag per more modern practice.

    To start with it seems to me I should remove the spindle, determine the size and type of bearings and then reassemble to specifications for comparable bearings from Torrington or similar. I've ordered MT 2, 3 & 4 test bars from India. The MT 4 is for my Clausing. Once I have those I can evaluate the stock bearings, alignment of the spindle taper, etc and purchase higher grade bearings if needed.

    There is though a question as to whether a plain journal bearing would be more cost effective for the purpose of eliminating periodic spindle errors. Even if the stock bearings are poor, I should be able to grind between centers using a toolpost grinder a collar to press on the spindle. Once that is done, it's just a normal plain tapered journal job. My Clausing is rather worn, but I should be able to use it if needed.

    So I'm very interested in opinions about roller bearings vs plain bearings for precision work.

    As I only intend to use this for toolroom class work, the 3 jaw is pointless. So I plan to turn away the mounting plate from the spindle. All work will be done using collets or a fixture plate mounted on a drawbar MT 3 arbor. I had considered balancing it, but on consideration don't think it worth the trouble. However, I will build a dynamic balancer for use when setting up work on fixture plates.

    As I am "reconditioning" a lathe, this seems the appropriate forum. I'm just working on a generic, no name machine that happens to be new. As I need it to make tooling for gauging precision RF connectors it is a convenient size and so long as I execute the work correctly should be as capable as any toolroom lathe of comparable size.

    For reference, the connectors I'm concerned with have tolerance limits of 0.0002". Out of spec connectors can destroy the mating connector. Aside from often being difficult to replace because of the manner in which they are installed, they are also quite expensive. I'm not going to be using 1 mm series RF connectors, but those sell for $1000 each. The ones I'm using are generally under $200 for quality units.

    Have Fun!
    Reg

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    I just ordered 6" and 12" castings from Gary Martin and had a nice chat. I'm sure I'll get some longer ones, but these will do for getting started.

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    Gary is a nice guy, I have done some business with him in past years, His castings are well done. He does nice work. And like you I have had a few nice chats with him. I have a couple of his triangle castings and 6" and 18 inch straight edges all scraped up. nice tools

    Quote Originally Posted by rhb View Post
    I just ordered 6" and 12" castings from Gary Martin and had a nice chat. I'm sure I'll get some longer ones, but these will do for getting started.

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    I have a few of my 18” prism/straight edge/ levels in stock. They are cast in my foundry in grey iron 40 and are thermally stress relieved. They ship in a USPS flat rate box and are sold as a raw casting or machined.

    Denis Foster 18" Straight Edge / Prism

    Denis

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    Quote Originally Posted by rhb View Post
    Thanks to all. I couldn't find any castings for metrology items on Martin's website, but I'll email him.

    I'd like to have some small spotting tools for the mini-lathe, however, I want larger tools for my larger machines. I'll be in touch by PM. I'll also take a scraper to my ductile iron bar and see what that's like. Scraping steel is tedious at best.

    I'm trying to buy a copy of the publications by Moore Tool, but am having trouble reaching anyone. There are used copies of "Foundations of Mechanical Accuracy" on Amazon for $5000! Totally crazy. I had it once on interlibrary loan, but could never find a copy for sale. I very much hope that it is actually available from Moore.

    With the forum moderator's indulgence I'd like to explain what I'm up to.

    A small Schaublin or Hardinge toolroom lathe is either expensive or in need of a lot of work. And replacement parts are expensive and difficult to get. Chinese mini-lathes are partially machined casting kits for toolroom purposes. But parts are easy to get at reasonable prices. So if I make a mistake, it's not expensive. And I'll learn a lot more than buying a brand name toolroom lathe in good condition.

    The big question I have at the moment is the spindle bearings. While I read less than 0.0001" TIR rotating it slowly, I have no idea if the bearing preload is correct. You can often make a poor bearing look good for a while by excessive preload. But it galls quickly. My Clausing lathe is a plain journal bearing. Those are pretty easy to understand and adjust. Ball and taper bearings are rather more involved. However, I have tooling to make any adjustment called for whether end play per air cooled VW practice or rotational drag per more modern practice.

    To start with it seems to me I should remove the spindle, determine the size and type of bearings and then reassemble to specifications for comparable bearings from Torrington or similar. I've ordered MT 2, 3 & 4 test bars from India. The MT 4 is for my Clausing. Once I have those I can evaluate the stock bearings, alignment of the spindle taper, etc and purchase higher grade bearings if needed.

    There is though a question as to whether a plain journal bearing would be more cost effective for the purpose of eliminating periodic spindle errors. Even if the stock bearings are poor, I should be able to grind between centers using a toolpost grinder a collar to press on the spindle. Once that is done, it's just a normal plain tapered journal job. My Clausing is rather worn, but I should be able to use it if needed.

    So I'm very interested in opinions about roller bearings vs plain bearings for precision work.

    As I only intend to use this for toolroom class work, the 3 jaw is pointless. So I plan to turn away the mounting plate from the spindle. All work will be done using collets or a fixture plate mounted on a drawbar MT 3 arbor. I had considered balancing it, but on consideration don't think it worth the trouble. However, I will build a dynamic balancer for use when setting up work on fixture plates.

    As I am "reconditioning" a lathe, this seems the appropriate forum. I'm just working on a generic, no name machine that happens to be new. As I need it to make tooling for gauging precision RF connectors it is a convenient size and so long as I execute the work correctly should be as capable as any toolroom lathe of comparable size.

    For reference, the connectors I'm concerned with have tolerance limits of 0.0002". Out of spec connectors can destroy the mating connector. Aside from often being difficult to replace because of the manner in which they are installed, they are also quite expensive. I'm not going to be using 1 mm series RF connectors, but those sell for $1000 each. The ones I'm using are generally under $200 for quality units.

    Have Fun!
    Reg
    https://frank.villaro-dixon.eu/publi...20-%201970.pdf

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    I ordered that and “Holes, Contours and Surfaces” by Richard Moore yesterday.

    I had Wayne's book on interlibrary loan many years ago, but could never find a copy at sensible prices. There three used copies on Amazon, one for $5000 and two for $354. Before the 3rd seller showed up, both sellers were asking $5000. Moore Tool sells them new for $150 and they keep them in print. Richard's book is $65.

    I like real books. I've got over 5000. Just the manufacturing processes section is 70+ ft of shelving. In all fairness, a lot of it is 19th and early 20th century. But for one off jobs with limited tooling, the old methods are still useful. Toolmaker's buttons anyone? And I have never found a book that comes close to "Foundations of Mechanical Accuracy".

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    Why yes! I just picked up some more Brown and Sharpe tool makers buttons the other day, dirt cheap. Source for a dovetail scraping reference?

    My name is Brian and I'm a toolaholic.

  16. #13
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    Quote Originally Posted by dgfoster View Post
    I have a few of my 18” prism/straight edge/ levels in stock. They are cast in my foundry in grey iron 40 and are thermally stress relieved. They ship in a USPS flat rate box and are sold as a raw casting or machined.

    Denis Foster 18" Straight Edge / Prism

    Denis
    I guess the notification above is working. I sent out 2 18's and a 36 this week. I am able to maintain stock at this time. I usually need a week or ten days lead time for machining. Shipping as-cast take can be done within a couple of days of receiving an order. 18's ship USPS Large Flat Rate box to the US and Canada. 36's ship UPS or Fedex per buyer preference.

    18" prism/str edge as cast and stress thermally relieved 190. About 10 pounds
    Machining both prism faces and the to rail 150 Roughly 9 pounds.
    Machining holes for precision vIal and surface for vial 60

    36" as cast 450 about 26 pounds
    Machining base and 45 deg face 175 Machined to a target weight of 24.5 ounds to 19 pounds per buyer preference.

    I have been able to machine the various faces of my SE's to less than .002" but claim less than .004 to be on the safe side. Local pickup is ideal from both a convenience aspect but also it is really a treat to meet you guys! I do pack them in a robust wooden fitted box for shipping. It is a fair bit of work to pack them up so I am going to start charging 40 dollars for crating.

    Contact me via PM or email using Practical Machinist's "send email function" which is accessed by clicking on my name and selecting "send email" from the menu.

    These are very nice castings tested for uniform softness and free of voids and cast from commercial 40 Grey cast iron. Satisfaction guaranteed.

    Denis

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  18. #14
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    Letting everyone know I just received a new order of straight-edge castings. So I have 12", 18" 24" and 36" camelback angle straightedges. Send me an Email if your interested. [email protected]

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    I meant to say in my post above that the 36" Featherweight SE is thermally stress relieved just as the Featherweight 18 is thermally stress relieved..

    I would have just edited the post, but for some reason the edit function does not appear on the forum at this time. Must be a glitch.

    Denis

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    Denis, I think the newer vb software has a timeout function on edit ability.

    cheers,
    Lucky7

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    I just found out my inbox has been full. If you have tried to send me a message that way, my apologies. It is cleaned out and I will try to keep it open, but it fills up rapidly and recently has not emailed me to so advise. Frustrating!

    My email is far more reliable and is [email protected]

    Denis

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    The cheapest way to make a prism straight edge is contact Dura-Bar Our Material Goes Straight From Your Receiving Door To Your Machine Tool When I make them, I buy the iron from them and they will saw any size you want. Usually under a hundred dollars. I also make Camel back Straight-edges. I can't figure out how Gary Martin can make his straight-edges so cheap. Warren had 2 at the VT class. Nice but a bit heavier then mine. PM me and I can send you a list. I also sell mine on Ebay where I have discriptions of them. Or email me . [email protected] . If you want to learn how to scrape them I can do that too.

    Also be sure to "ring vibration stress relieve" them while your scraping them. We just proved how well it works at the last Vermont class when one of the students brought a 50 year old 30" camel back straight-edge from work that had been sitting on wood blocks he figured at least 20 years. We checked it and recorded the hinge point and then hung it from a engine hoist, hit it several places with a dead blow hammer and tested it again on a Grade A surface plate and it moved almost 2" on both sides. We had several degreed engineers in the class who saw this test and how it changed.

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    What does a piece of durable 18 x 2.5 x 3 cost with shipping and what is a good source?

    Denis

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    Last time I ordered some Dura-Bar. I ordered a different size, but it's cheap and they claim because it is extruded iron no stress relieving is needed. I get my camelbacks cast at a foundry and high temp stress relieved but one would be foolish to buy prisms when you can buy them cut by Dura Bar IMHO

    I bought this in 2016

    1 0.750"H X 3.625"W X 36.125"L 1 25.5 lbs 26 $70.228/EA $70.23
    GRAYIRON G2 IRON CUT PLATE
    material to finish to 0.625" x 3.500" x 36" Shipping was from Wood stock IL to Cottage Grove MN

    Shipping & Handling 1 $10.00/EA $10.00 They have a special rate for parts under 70 pounds. It's $10.00

    I bought this one in 2017:

    12 - 0.875"H X 3.625"W X 12.125"L - 10.0 lbs (ea) 120 (pounds) $66.587/EA $799.04
    GRAYIRON G2 IRON CUT PLATE ( and they were also Blanchard Ground)
    2-3 week lead time
    Blanchard grind to .75" x 3.5" x 12" +/-.005

    Total Value of Quotation Based on Estimated Weight: 120 lbs $799.04

    I buy mine from the Woodstock IL plant. I believe they have a CA plant too.

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