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  1. #1
    Join Date
    Sep 2012
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    York, North Yorkshire UK
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    6,439

    Thumbs up Dial Graduating Tool !

    Hi Guys,

    I am in need of a suitable tool to graduate calibrated machine dials. I have a very nice set of "Pryor" 1/16" inch letter and number stamps. These are normally secured in a hand held holder to use them. They would be ideal for what I need to do.

    I've spent the day designing a jig that I can use to stamp graduations and numbers onto an aluminium dial. The idea is to hold the stamp securely whilst impacting it with a uniform weight, thus ensuring that the characters all have the same appearance.

    The drawing below is the result !

    Dial-Graduating-tool-01.png

    The material is 12 mm steel plate held in an "L" shape supporting a spindle upon which the dial can be mounted. This spindle is drilled and tapped in the free end M4 or M5 so that the dial can be secured. A 3 mm thick plate is used to hold the punch and the stamp. The height of the punch is adjustable to accommodate dials from about 1" inch diameter up to 2" inches diameter, and fixed in position by two M6 cap screws. The punch holder is fastened to the adjustable plate by four M3 csk screws. The punch itself is a short length of 4 mm unhardened drill rod.

    I have still to complete the drawing with the side view of the punch holder.

    Comments and suggestions welcome !
    Best Regards:
    Baron J.

  2. #2
    Join Date
    Dec 2013
    Age
    56
    Posts
    1,416

    Default

    You will have to experiment with how much force for each letter, as an I or 1 takes little force, where a W or 8 takes more force.

    Maybe different weight hammers or better still a custom made sliding weight and just let it drop under it's own weight at a known tested position for each letter.

    I've done it a fair few times now, and noticed I've had to go back over the larger letters or numbers to get the same depth.

    Sent from my 5007U using Tapatalk
    Using Tapatalk

  3. #3
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
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    6,439

    Default

    Hi Dave, Guys,

    I hadn't realised that different symbols required a different force on them in order to get uniform impressions !
    I was thinking of using a spring to drive a weight down onto the top of the stamp via the 4 mm rod.
    The stamps are very small, only 1.5 mm thick by 3.5 mm wide and 15 mm long. Ideal for this sort of dial markings,

    I'll post a picture later.
    Best Regards:
    Baron J.

  4. #4
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Guys,

    I said that I would post pictures !

    05-04-2021-001.JPG 05-04-2021-003.jpg

    05-04-2021-004.JPG 05-04-2021-002.JPG

    This is the set of "Pryor" interchangeable type that I have. The set was originally purchased in the late 1940's and given to me in the late 1980's by my then mentor and very good friend, and have had very little use by me.
    So I thought that I would put them to use.

    I've made a start on the jig as indicated in the drawing. I have a piece of scrap 12 mm plate that I marked out and cut to size using my bandsaw.

    05-04-2021-005.JPG 05-04-2021-007.jpg

    05-04-2021-006.JPG 05-04-2021-008.jpg

    As you can see the piece of plate is just too big to go in the bandsaw vise. so I removed the moving side along with the screw and used a "G" clamp to secure it whilst cutting. I also put a piece of 30 mm round bar under the plate at the fixed jaw side. The last picture is the cut off pieces. I also cut the 50 mm long piece from the end of the 70 mm wide piece. Because there was a saw cut in the edge I had to cut a 10 mm wide strip off to get rid of it.

    I'll cut the other pieces later.
    Best Regards:
    Baron J.

  5. #5
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    Does not have to be too complicated. This is a stamping jig I made mainly from flat bar back in '08 for a round dial on my lathe -
    jig.JPG

    Michael

  6. #6
    Join Date
    Sep 2012
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    York, North Yorkshire UK
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    Default

    Thanks Michael,

    Part of the design is that the stamps are tiny compared to a set I found in the scrapyard which are 1/4" square. I would like to be able to make the jig use other sizes of stamps. I'll post pictures as I go along.

    The "Pryor" ones are only 1.5 mm thick and the holder that is supplied is designed to hold 25 pieces at a time. There are a lot of blank pieces that are used as fillers alongside the letters & numbers. Unfortunately I don't have the original instruction and parts manual that came with it. However I believe that Pryor still make this set along with many others.
    Best Regards:
    Baron J.

  7. #7
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    That holder will work if stamping on the flat, but if you try to stamp on a curve you will only get the middle letters (that is, the ones at the tangent point). You'll have to stamp individually.

    Not saying you have to do it this way at all, but on the jig I pictured, the stamps are held in a square slot, with a piece of flat completing the 4th side. You could make up several of those plates with different size slots for different size stamps.

    Michael

  8. #8
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    574

    Default

    To graduate and stamp the various parts of my homebuilt T&C grinder, I made a hand operated tool similar to a slotting tool that fitted in the lathe tool post and also a holder for the number stamps that also fitted in the lathe tool post, the slotting tool has an indexable 3 position stop so I could scribe(engrave) lines of 3 different lengths, the number stamp holder only held one stamp, so only one number could be stamped at a time, I felt this was the best way to do a curved surface, also it meant I could control the spacing between the numbers .
    After turning the part I jury rigged my rotary table to the rear of the lathe clamping it to the lathe spindle - starting at 0, I went around the whole 360deg scribing only the major 0 marks 0,10,20,30,40 etc - using the longest stroke on the slotting tool, I then did another 360 deg for the intermediate marks 5,15,25,35 etc using the intermediate length stoke of the slotting tool and lastly I scribed(engraved) the remaining lines (shortest ones).
    I reset the rotary table back to zero and mounted the number stamp holder in the tool post and with a piece of masking tape on the work piece so I could see exactly where the number was being stamped I setup the number stamp holder so it would stamp exactly over the zero mark, it only needed finger pressure to mark the tape, with more masking tape and some trial end error I worked out how far to move the rotary table either side of the 0 mark so 2 digit numbers looked correctly positioned over the mark, I think it may have been around 2 deg, but it will vary depending on your number stamps and the diameter of the work piece being engraved.
    The procedure was - set the rotary table on a zero mark, move 2deg back - stamp a number - move back to the zero mark and forward another 2 deg - stamp a number - all the way around 360 deg doing the 0,10,20,30 etc marks. The intermediate 5 divisions were done next - this was a bit easier as it was just go around the whole 360 deg stopping at the 5 mark, the 5 division was shorter so I needed to reset the position of the stamp slightly back.
    The Quorn indexing tool holder is marked in 4 quadrants of 0 to 45, the deg marks are 0,5,10,15,20,25,30,35,40,45,40,35,30,25,20,15,10,5,0 so if the index mark is set on 0 the divisions either side are 5 ,10,15 etc.
    I didn't take pics but I hope you can make some sense of my description, you may think of a better way and I don't doubt there probably are better ways - but there is plenty of room for error and there is only a limited number of times you can skim the engraving off and start again if you make a mistake, the other way to do it of course is to farm it out a professional workshop.

  9. #9
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
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    6,439

    Default

    Quote Originally Posted by Michael G View Post
    That holder will work if stamping on the flat, but if you try to stamp on a curve you will only get the middle letters (that is, the ones at the tangent point). You'll have to stamp individually.

    Not saying you have to do it this way at all, but on the jig I pictured, the stamps are held in a square slot, with a piece of flat completing the 4th side. You could make up several of those plates with different size slots for different size stamps.

    Michael
    Thanks Michael,
    All the stamps are the same thickness, 1.5 mm so I had already decided that using single stamps was the way to go.

    I watched a video, some time back where a string of characters was embossed into a round surface. The stamp was run across the surface of the round from one side to the other impressing quite a long sentence onto the surface. I've also seen the same technique used for printing onto the curved surface of bottles and jars. Multiple colours done in several passes.
    Best Regards:
    Baron J.

  10. #10
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

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    Hi Family Guy,

    Nothing so sophisticated, I need 40 divisions on a 50 mm diameter ! The leadscrew thread is M6, so 1 mm or 40 thou per turn. I do have a gear with 40 teeth but that will only give me 39 detents, so I've printed off a 40 division scale that I can glue onto the work and use a pointer.

    More pictures to come...

    Thanks:
    Best Regards:
    Baron J.

  11. #11
    Join Date
    Nov 2011
    Location
    Port Sephens NSW Southside
    Posts
    123

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    BaronJ
    You could make a locator to straddle the peak of the 40 tooth gear instead of the valley.

    JohnQ

  12. #12
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Thumbs up Drawing !

    Hi Guys,

    I have finished the drawing for the Graduating stamp holder tool. So unless I've made any mistakes there shouldn't need to be any changes.

    Dial-Graduating-tool-01.png

    The main body is made from 12 mm steel plate. A three mm thick steel plate with slots cut into it is used to mount the punch body. The pale blue holes are threaded M6 and the holes in the punch holder are threaded M3 with the holes in the slotted plate opened out to clear and countersunk to match the screw heads. By moving the slotted plate up or down different diameter dials can be marked, in this case from about 1" inch upto 2" inches in diameter.

    The support pin for the dial is 6 mm diameter and is pressed into a reamed 6 mm hole in the backplate. A hole threaded M4 in the end of the pin will be used to hold the dial being marked in place. The backing washers can be used to set the dial stamping position. I propose two of them.

    The idea of doing it this way is so that the punch holder can be changed to suit other size punches. For the 1/16" inch stamps that I propose to use, a slide hammer, a simple weight dropped from a known height guided by a steel rod should ensure consistent impressions. This will be a simple rod screwed into the top of tool body to guide the hammer.

    Comments welcome ! Thanks Guys:
    Best Regards:
    Baron J.

  13. #13
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

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    Hi Baron
    Quote Originally Posted by BaronJ View Post
    I do have a gear with 40 teeth but that will only give me 39 detents,
    What now?(unless you count a rack or I am missing something)

  14. #14
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
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    Default

    Quote Originally Posted by Stustoys View Post
    Hi Baron

    What now?(unless you count a rack or I am missing something)
    Hi Stuart,

    Well your reply prompted me to actually count the spaces between the teeth of the gear rather than to assume !
    Which I had. The gear is clearly marked 40T and for whatever reason the number of teeth minus 1 popped into my head.

    So thank you for the push in the right direction !
    Best Regards:
    Baron J.

  15. #15
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Thumbs up Backplate marked out !

    Hi Guys,

    I've been cleaning up the pieces of steel that I cut up ! I've machined two pieces to size and using my new DRO marked and spotted the position of the holes to be drilled. The DRO makes it too easy ! Find the edges, zero the DRO and work to the numbers.

    13-04-2021-001.jpg

    Here I've marked all five hole positions three 6 mm diameter and two 5 mm diameter, the tapping size for M6. The hole in the middle was actually drilled 5.9 mm. For reaming to suit a piece of 6 mm diameter ground bar press fitted. In actuality I didn't end up reaming it to size since the ground bar was a gentle push fit ! So that will get Loctited in place.

    13-04-2021-003.jpg

    This is the finished backplate with the holes threaded and the bottom ones countersunk. I've used M6 CSK screws in the places where they will go.

    13-04-2021-004.jpg

    This is the piece waiting to be threaded M6 ready to fasten into the bottom of the backplate. I used the DRO in the same way as I had done for the backplate and drilled them 5 mm ready for threading. Once threaded I will find out just how accurately it fits.

    13-04-2021-002.JPG

    Whilst I was milling I fly cut this piece so that it was 12 mm square and 50 mm long. This piece has to be drilled 4 mm diameter to within 13 mm of its length and then slit at one end to suit the stamps. It also needs four 2.5 mm holes put in it and then threading them M3.

    More later.
    Best Regards:
    Baron J.

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