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  1. #16
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Kryn,

    Thanks for your comments.

    Mmm, I don't know if it was scrapped because of the crack ! It was pretty much in the middle of the piece that I had and unless they have ultrasonic crack detection equipment it would have gone unnoticed. I didn't find it until I took a cut off the sawn edge, there wasn't any sign of it in the other piece. Having said that, the crack was only a few mm deep. When I saw it, I expected it to grow in size as I machined it.

    This EN16 seems to be quite tough, taking a 40 thou cut seemed to load the motor more than I expected it to.
    Best Regards:
    Baron J.

  2. #17
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Guys,

    I've managed to do a little more on the TC grinder base today. One problem that I immediately hit was that I didn't have enough headroom on the mill to drill and tap the holes in the end of the base piece. The obvious solution was to remove the X-Y table from the Fobco drill press base and use a six inch 90 degree angle plate to support the work while I drilled the spotted holes to a depth of 20 mm with a 4 mm drill and then drilled out to 7 mm tapping size for M8. Since I discovered that I had some M8 countersunk hex screws. Using those nicely gets me around having to counter bore Allen cap screws which would only leave 2.5 mm material under the head.

    06-04-2019-003.jpg 06-04-2019-002.JPG 06-04-2019-001.jpg 06-04-2019-004.jpg
    The first picture shows the spotted holes and the others the setup used to drill to size and thread M8. I used a 7 mm drill as the nearest larger size to the recommended 6.80 mm for a 70% thread. The last picture is the threaded holes and the three M8 counter sunk Allen hex screws. The screws are too long and will need shortening by about 15 mm, that end screw has bottomed in the hole.

    I now intend to make a start on the piece for the other end.

    Thanks Guys.
    Best Regards:
    Baron J.

  3. #18
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Thumbs up New Front Plate drawing.

    Hi Guys,

    I've done a new drawing for the front plate based on using M8 Countersunk Allen hex head screws. I've also added some dimensions that I had missed on the previous one. M8 is definitely a better fit for the 12 mm thick front plate. Please disregard the previous drawing.

    Base front Plate.png
    This drawing still needs the hole for the top slide traverse mechanism to be added since I don't know exactly where it should go yet.

    I've got the rear plate to make and will make any needed corrections to the drawing and post it here.

    Thanks Guys.
    Best Regards:
    Baron J.

  4. #19
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Thumbs up Rear end Plate.

    Hi Guys,

    Started work on the rear end plate today. This is the one that is an inch thick and has the 20 mm diameter vertical post supported in it.

    08-04-2019-003.jpg 08-04-2019-004.jpg
    I first of all spent some time cutting a 151 mm length of 25 X 50 mm steel bar, actually only need 149 mm but allowed a couple of mm for cleaning up the ends. Then I marked out all five hole positions and centre popped them.

    08-04-2019-002.jpg 08-04-2019-001.JPG
    Next into the mill and squared up the sawn ends. One end only took a 0.5 mm cut to clean it up, the other took just over a millimetre. My hacksawing isn't as good as it used to be It was square across the end but sloped out a bit towards the bottom. Anyway the ends cleaned up just fine.

    08-04-2019-007.jpg
    After which I drilled and reamed the ten mm diameter hole for the split clamp pin.

    08-04-2019-005.jpg 08-04-2019-006.jpg
    Here I've turned the 10 mm pin for the split clamp from a piece of 12 mm printer guide rod. I still have to drill and thread this pin M4, so that I can use an M4 cap screw and washer from each end to secure it in the reamed hole. Because the tap will not go all the way through, I will have to tap at least half way from each end.
    Best Regards:
    Baron J.

  5. #20
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Guys,

    Did some more on the rear plate, started drilling out and boring the large 20 mm hole.

    09-04-2019-001.jpg 09-04-2019-002.jpg
    Here I've completed the drilling and threading of the M4 hole in the split clamp pin.

    09-04-2019-003.jpg09-04-2019-004.JPG
    This is the finished pin ready to be fitted into the hole in the rear plate.

    09-04-2019-006.jpg 09-04-2019-007.jpg
    Annoyingly enough, it fits perfectly except that it is 0.45 mm too long ! Moral here is to use the same measuring tool that I used to measure the bar thickness with. My two callipers disagree with each other about how big 25 mm is. One is a Aldi special and the other is an imperial Moore & Wright dial calliper, Unsurprisingly neither agree with the 25 mm standard that came with my metric micrometer. Not a problem to face off a few thou.

    09-04-2019-009.JPG 09-04-2019-008.jpg
    I used a 4 mm drill to pilot a larger 10 mm drill, then a 18 mm one to put a hole right through the 50 mm width of the bar. In this picture I had forgotten to put the 10 mm split clamp pin in place. Fortunately the 10 mm drill doesn't cut into the hole for the pin.

    09-04-2019-010.jpg 09-04-2019-011.JPG
    Since I don't have a 20 mm drill I resorted to using a boring head to open out the hole. I didn't realise that the boring bar wouldn't go all the way through without the shoulder catching the top of the hole. No real damage done, I've still about 20 thou to go before I get to size. I'm using a 20 mm carbide milling cutter shank as a test gauge for the hole.

    With a bit of luck I might get chance to finish this part tomorrow and then split the clamp pin.

    Thanks Guys.
    Best Regards:
    Baron J.

  6. #21
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    281

    Default

    You certainly aren't wasting any time and look to be making good progress, I'm not familiar with the brooks TC grinder so I had a look on youtube and I see quite a few variations, where people have modified the basic design just as you mentioned in your first post.

  7. #22
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Familyguy, Guys,

    Yes I'm trying to get as much as I can done before going away tomorrow for six weeks.

    The XY table part of the Brooks design is the most critical bit. You have to be able to move the work piece in all axis accurately and precisely. I'm considering the ball races at the moment running in slots down the sides and top, but there are other ways of guiding the table. Dovetails is one, brass or bronze rails is another besides the original round bar guides, and I haven't even got to the tool holder yet.

    Being able to do 2D drawings helps greatly. I use the free Qcad software, though the professional version is excellent value for money. There is also the CAM version, but I don't have any CNC machines.

    Part of what I'm trying to do is to make the machine easy for people to copy and make their own TC grinder.

    Anyway thank you for your comments ! All input is of value and welcome.

    Thanks Guys.
    Best Regards:
    Baron J.

  8. #23
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    281

    Default

    It's always good to see what others have done - I saw on youtube a guy has made some modifications and uses linear bearings for part of the X-Y table, in case you haven't seen it you might want to have a look https://www.youtube.com/watch?v=8ns7I6jwyIw

  9. #24
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Guys,

    Scrub going away tomorrow ! It helps not to look at last years booking form
    So will still be around for another two weeks

    Back into the workshop !
    Best Regards:
    Baron J.

  10. #25
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default New Rear Plate Drawing.

    Hi Guys,

    I've done a new rear plate drawing to correct a couple of errors !

    Rear End plate.png
    The split clamp pin centre line should be 25 mm and not 24 mm as on my original drawing, as I found out the 20 mm bore hits the M4 screw thread and damages it. Also the thread through the spilit clamp pin should be drilled and threaded for an M4 screw. I had originally labelled it M5.

    Thanks Guys.
    Best Regards:
    Baron J.

  11. #26
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Hi Guys,

    I forgot to put this picture in the previous post, showing the inside of the 20 mm bore with the damaged M4 thread inside.

    11∕04∕2019.001.jpg

    I've yet to ream out to size there is about 5 thou in there to take out. The piece of bar that goes in there is a length of hydraulic piston and is spot on 20 mm so I hope that the reamer is a plus 5 one.

    Thanks guys.
    Best Regards:
    Baron J.

  12. #27
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default Split Clamp.

    Hi Guys,

    I got the hole in the rear plate reamed out with a 20 mm reamer.

    11-04-2019-001.jpg
    This picture shows the after reaming to 20 mm and the split clamp pin removed. I had to put the 10 mm reamer back through the clamp pin hole because it got burred when I removed it, by tapping it out with a hammer and punch. It was really tightly fastened in there.

    11-04-2019-003.JPG 11-04-2019-004.jpg 11-04-2019-005.jpg
    The 20 mm bar was a very good fit in the reamed hole. The bar passes through cleanly without any binding. That last picture is a view through the clamp pin hole showing the amount of bar available to clamp. I've still got the fastening holes to drill through in this part.

    11-04-2019-002.jpg
    This is the clamp pin waiting to be split and one half drilled out to clear the M4 cap screw.

    11-04-2019-006.jpg 11-04-2019-007.JPG 11-04-2019-008.jpg
    Here the clamp pin has been cut in half and all the edges deburred. You can see the file marks on the edges at the bottom of the scallop. It is very important to remove the burrs on those edges, because if you don't they will dig into the bar when you tighten the clamp and become difficult to remove also you will scare the bar and have difficulty in removing it from the hole.

    The next picture shows the counter bored end with the M4 screw holding the two half’s together. the counter bore done with a 7.5 mm drill and the bottom was flattened with a drill that had the tip ground flat. A lot less costly than buying a spigoted one.

    In use those two clamp pin half's will grip the bar and prevent any movement at all ! It is a very reliable, secure method of holding something that you don't want to rotate or lift. Indeed I would apply some lubrication to those parts because if they rust at all you may never get them apart as easily as they should be.

    You will note that the cap screw protrudes into the space occupied by the 20 mm bar ! My method for resolving this issue is to turn down the middle so that it clears the 20 mm bar and allows enough for it to tighten without it fouling.

    Thanks Guys.
    Best Regards:
    Baron J.

  13. #28
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Thumbs up Back plate drilled.

    Hi Guys,

    I've got some more done on getting the base and front and rear plates drilled and countersunk. I've still got to put a waist on the split clamp screw to clear the 20 mm column.

    13-04-2019-004.jpg
    The rear plate marked out and the position of the holes centre popped. The front plate has already been drilled and countersunk.

    13-04-2019-007.JPG
    Here I am drilling 4 mm pilot holes so that I can transfer mark the hole positions for the back plate onto the end of the base plate. I used a 50 mm length of 4 mm diameter silver steel that has been hardened and then had a point ground onto the end of it.

    13-04-2019-011.JPG
    These pop marks are where the base plate has to be drilled 7 mm tapping size for M8 screws.

    13-04-2019-003.jpg
    This is the front plate with the holes drilled out to 8 mm and countersunk for the screws that hold it onto the base plate. I had to shorten these screws by 12 mm so that they didn't bottom in the threaded holes.

    13-04-2019-001.JPG 13-04-2019-002.jpg 13-04-2019-005.jpg
    I made a threaded collet to hold the screws whilst I parted off the ends. I used a 6 mm deep by 2 mm wide parting blade mounted in the front tool holder.

    13-04-2019-006.jpg
    I found that the front plate was a just over a mm too long. A bit difficult to see in this picture. So I fly cut it down so that it is flush with the edge of the base plate. There should be a picture of that but it seems not to be!

    13-04-2019-008.JPG
    After drilling I used a Weldon countersink in the drill press to counter sink the holes. I run the drill at its lowest speed, about 450 rpm for this job.

    13-04-2019-009.jpg 13-04-2019-010.jpg
    I've no need to shorten these screws because of the 25 mm thickness of the rear plate they don't bottom out in the threaded holes in the base plate.

    Well that is it for today, now to take the wife shopping.

    Thanks Guys.
    Best Regards:
    Baron J.

  14. #29
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    281

    Default

    I see you are still maintaining the pace on the build, pity about that split cotter being slightly out of place, those split cotters (if that is what they are called ?) do hold really well I've used them right through my T&C build I used 0.5inch brass rod for the cotter and a 1/4" bolt to clamp up.

  15. #30
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,050

    Default

    Good Morning Familyguy,

    Thank you for your comments ! Its nice to know people are reading my posts.

    Yes a rookie mistake. But I did go back and correct the drawing. Why on earth I made that error I don't know. One of the beauties of CAD drawing is that you can get the dimensions correct.

    I wanted that split clamp pin centred vertically in the back plate but didn't want to foul the edge of the base plate, which is why I chose 10 mm diameter and a M4 cap screw. If I had got the dimension right there would have been about 30 - 35 thou of clearance between the threads and the 20 mm bar.

    14-04-2019-005.JPG
    Here you can see just how close that split clamp pin really is.
    As it worked out turning the threads off just the middle 10 mm of the M4 screw was enough to enable sufficient clearance.

    There seems to be a different name for those split clamps in different parts of the world. A cotter pin here is usually a tapered pin with a thread on the end used to pull it into the joint and make it semi permanent, and a plain cotter is simply a headed pin with a small hole across the the end for a split pin and is normally a loose fit.
    Best Regards:
    Baron J.

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