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Gear Cutting, yes or no...

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  • Guest's Avatar
    Guest replied
    Similar to Dave Powel's story, my BIL was in the Navy. He was an engine room chief. One day, a brass gear that somehow fed the ship's speed to the bridge failed. While his crew was content to wait until they got back to port to get a new part, my BIL got a blank and cut a new gear with a hacksaw. He made the crew watch. It lasted until they got in to port.

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  • oldtiffie
    replied
    Getting properly stiffed and shafted - all for the good gear!!

    Originally posted by Davek0974
    Is a Bridgy horizontal attachment man enough for the task??

    Dave
    Dave, I would think that it might.

    The biggest problem in most cases with larger gears particularly is keeping everything on the mill out of the swept arc of the outside diameter of the gear blank. A stub arbor in the vertical head of a BP mill may be better than a stub arbor in the standard BP vertical head.

    A horizontal milling attachment may or may not be better - but as before - I will leave advising on that to those that have used them.

    This post by Tim Leech makes it very clear!! Note how far the arbor supports are apart and how slim the arbor, even with the stiffening of spacer, is.

    Originally posted by Timleech
    Here it is, the pics are still out there although I gave up the ISP a couple of years ago







    It's a flywheel of about 150 to 200 kg, rotary table hooked up to my CNC Bridgy but the job is on a manual mill.

    Tim

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  • David Powell
    replied
    A very different size of job.

    Over 30 yrs ago I needed a gear for my model steam roller. I could have stolen a change gear from the set of my ancient lathe ( 10 dp 70 teeth) but needed it on the lathe, I had little equipment, less knowledge and No spare money. One day i spied a large washer of about the right size hanging as an additional weight on a friend.s power hacksaw, I came home with the washer, found it was exactly the size I needed and came up with a scheme. I bolted the washer to the gear, drilled a 1/16th hole at the bottom of every tooth, scribed the teeth on, and hacksawed 70 vees. Then I bought 3 triangular files and filed for 3 weeks until I got a gear that looked passable!!, I built a rough frame, meshed it with a proper gear and filed until it would run smoothly with reasonable backlash. The gear is still in use on the very hard worked model. Obviously you would not want to file very large gears, but if you had a way of getting approximate teeth ( Of the right number!!!) on the blanks then perhaps a little filing could be used to smooth any major roughnesses. I knew a fellow with a full size engine who built up his terribly worn gears with weld, shaped them with an angle grinder, ran them in with lots of grinding paste and his son is still running the engine 40 yrs later, Have fun work safe. Regards David Powell.

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  • Circlip
    replied
    If you made a cutter to go in the collet chuck, similar to an end mill but with the profile of the "Slot" between the teeth, tilt the vertical head over by 90Deg (Like the horizontal drive but in LINE with the table) and mill the slots.

    Regards Ian.

    Sorry, Pre-gash most of the waste out first, as his worship has suggested.

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  • John Stevenson
    replied
    I think so in cast iron.
    Especially if you pre gash first with a thin saw.

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  • oldtiffie
    replied
    If only .......................................

    Originally posted by John Stevenson
    Problem with a slotter is Tiffie that although you could get the biggest gear on mine you couldn't get anywhere near the outside because of restrictions in the slides movements as the rotary part of the table is built in.

    My old slotter could have done it because that one had had the RT removed at some stage and replaced by a XY table.

    That could be removed and a RT mounted on it off centre so the edges could be reached.

    ...........................................
    ............................................

    .
    Thanks John.

    I got spoiled years ago in the milling section of which the shaping/slotting sub-section was part.

    They were really big reliable accurate first-class machines - "Butler"s - every one. They really were incredible machines. I thoroughly enjoyed my time there - same as the gear-making section - hobbers, shapers etc. Mills were a range from Cincinnati, some Chec machines as well as a couple of "Victoria" horizontals - just like yours (great machines) - plus others.

    That's why I keep banging on about my next (dream) mill - Chinese of course - being a horizontal/vertical combo turret mill with a slotting attachment.

    If the discussion has helped the OP and anyone else as regards gear-making, cutter making and the uses of slotters it can only be judged a success.

    Many thanks.

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  • Davek0974
    replied
    Is a Bridgy horizontal attachment man enough for the task??

    Dave

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  • John Stevenson
    replied
    Yes, you did.

    Just now.

    .

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  • Circlip
    replied
    Nobody mentioned the Bridgy Slotting Head???

    Regards Ian.

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  • Davek0974
    replied
    If the horizontal attachment has the balls to do it, that seems to be the best option, costy but useful in the future.

    I think they have a 1" arbor, but dont know about the cutters yet, it may need a bush or bigger arbor?

    Thanks for the offer Tim, i'll PM when ready.

    Dave

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  • Timleech
    replied
    Dave, let me know if you go ahead and are struggling for a cutter.
    just checked, I've got 4DP nos 1 & 2. Don't really want to sell them but I'm sure we could arrange something.

    Tim

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  • jimmstruk
    replied
    Davek0974, go for it if you can come up with the horizontal kit (if you dont already have one). Malc-y explains very nicely the kit, Timleech shows how to use in his pictures. That makes the Bport into a horizontal machine and does not require any extra floor space. Also the angle head attachment used alone opens up many more options on other jobs not otherwise easily done.JIM

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  • John Stevenson
    replied
    Problem with a slotter is Tiffie that although you could get the biggest gear on mine you couldn't get anywhere near the outside because of restrictions in the slides movements as the rotary part of the table is built in.

    My old slotter could have done it because that one had had the RT removed at some stage and replaced by a XY table.

    That could be removed and a RT mounted on it off centre so the edges could be reached.

    Dave if you want to farm the job out, I thought you wanted to do it yourself, I can recommend Cornish Engineering in Nottingham, they will speak to you.
    Don't be put off when John answers the phone, he's 84 but bright as a button, that guy has forgotten more about gear cutting that I'll ever have chance to learn.

    I think his max gear size is eight foot diameter by two foot face and will go down to 1DP.

    .

    .

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  • oldtiffie
    replied
    Get slotted!!

    Dave,

    I had a look at your web sites - great work!!

    Another option which should be a lot easier would be to use a single tool in a good solid slotter - aka vertical slotting machine - (like a vertical shaper) with a good big rotary table on the slotter table. It is a solid as hell and solves most of your concerns. They are absolutely marvelous for internal keyways and internal gears etc. and like shapers, they are "tops" for male and female dove-tails. If I had a chance at both but was limited to either a shaper or a slotter - I'd take the slotter.

    I recall one that would be just the right machine in an old pic of John Stevenson's shop.

    I'd suggest PM-ing or faxing John Stevenson as he will not only know all about that machine of his but where there might be others that you could see or use.

    Are there any slotters in the shop's of hobby club members?

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  • Davek0974
    replied
    Thanks Guys, good advice.

    It's looking "possible" but full of difficulties. I will look into it further as soon as i get the mill clear.

    I am in the UK so that compounds the troubles more as we have bugger all access to affordable companies any more that are willing to even talk to HSM'ers like me

    Yes the gears run in the open with very little cover, they could likely even be hand cut and filed if i had nothing else to do for a couple of years.

    Dave

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