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  1. #1
    Join Date
    Jul 2009
    Location
    Brisbane
    Posts
    48

    Default Need some help with some stripped gears in my Beavermill

    Hi All,

    While doing some milling yesterday I noticed that the X axis feed on my Beavermill VBRP was slipping intermittently. It would drive for about half a revolution then slip then drive again.

    When I removed the feed gear box I found the following.

    Beavermill gears.jpg

    How it was feeding at all I don't know.

    The gears are 20 and 24 tooth. I can't measure the small gear accurately due to the damage. The 24 tooth gear has a diameter of 1.3 inches.

    Despite much googling, I am unsure of the specifications of these gears. I think they are 20DP and 14.5 degrees PA, but I am not sure.

    I have been trying to find a company who may be able to supply the basic gears but have not found anyone listing 20DP.

    Can anyone help me to identify these gears and maybe suggest a source for them. I am thinking that the best way to handle this repair might be to turn off the old teeth and bore out some new gears and heat shrink them on to the original blanks.

    Alternatively I would be keen to buy a set of gear cutters and have a go at making them myself if anyone knows where they are available from.

    Thanks for any help you can provide.

  2. #2
    Join Date
    Jun 2005
    Location
    Townsville, Tropical Nth Qld.
    Posts
    225

    Default

    PCX, if you are talking about the gears in the power feed, you should be able to get them from machinery suppliers as most of them are all clones of an original.
    Rgds,
    Crocy.

  3. #3
    Join Date
    Jul 2009
    Location
    Brisbane
    Posts
    48

    Default

    Thanks Crocy.

    Unfortunately this is a 9 speed gear bod made specifically for the Beavermill by the manufacturer. I have been told that parts are unavailable now.

    Sorry I should have included some pics of the gearbox.

    Beavermill gearbox 3.JPGBeavermill gearbox 2.JPG

    There you go.

    Baron I did include a picture which I can see when I click on it. If you can't see the attachment then I have obviously done something wrong.

    Will try to figure it out.

  4. #4
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,443

    Default

    Hi Graeme,

    I can see the pictures above just fine ! It may pay to edit your first post and re-add the picture.
    Best Regards:
    Baron J.

  5. #5
    Join Date
    Jul 2016
    Location
    Melbourne
    Age
    35
    Posts
    1,522

    Default

    You can readily get involute gear cutters from import sources like aliExpress and similar, I have bought from a few sources but the ones i got from mag-pro in Melbourne were the best of the bunch (they have the depth of cut engraved on them which was nice) i think i full set of mod2 cost me about $120, how sure of the pressure angle are you? do those gears mesh with others or just each other?

  6. #6
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Quote Originally Posted by caskwarrior View Post
    You can readily get involute gear cutters from import sources like aliExpress and similar, I have bought from a few sources but the ones i got from mag-pro in Melbourne were the best of the bunch (they have the depth of cut engraved on them which was nice) i think i full set of mod2 cost me about $120, how sure of the pressure angle are you? do those gears mesh with others or just each other?
    Hi there. First off i would google search the particular make/model to see if you can find a spec sheet or drawings of the gearbox. That may give you the exact specs for the gears PA etc. Rather than trying to guess.

    Failing that, i would attempt some careful measurement of these gears to determine the MOD/DP and PA. Perhaps this info can be obtained from some of the other gears in the gearbox.

    If the gears only mesh with eachother then you may be at an advanrage to choose the PA 14.5 or 20 degrees. But you would need to make sure the separation of the axes of the gears is not affected by changing the PA as im not sure. ie make sure they still mesh if you change the PA.

    Failing that, make an educated guess of the PA given its make, country of origjn and date of manufacter. Make a set of gears and see how you go.

    Good luck!

    Simon

    Sent from my SM-G900I using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  7. #7
    Join Date
    Aug 2008
    Location
    near Rockhampton
    Posts
    6,216

    Default

    Are you any good at CAD?

    Fusion 360 has a gear maker add on. Model gear, print out a thin sample on a 3D printer and see how it compares.
    Gold, the colour of choice for the discerning person.

  8. #8
    Join Date
    Jul 2009
    Location
    Brisbane
    Posts
    48

    Default

    Thanks for the input guys.

    No chance of me doing anything with a CAD program.

    The mill was made in England probably in the 60's so I am comfortable with my 20DP calculation (if I have understood the formula I got from Google. ie. number of teeth plus 2 divided by the diameter of the gear). I have been able to measure some other gears in the box with the same result.

    Not so sure about the pressure angle. As I understand google one way to estimate the pressure angle is to measure the distance across the root of 3 teeth then the distance across the root of 4 teeth and subtract them. Doing this consistently results in a difference of close to 145 thou so I am guessing this means a 14.5 deg PA. I may however, not have understood the article properly. This article said it could be any number of teeth that can be measured accurately. ie 2 and 3, 3 and 4, 4 and 5 etc.

    If this is correct I have found a company in the US that is advertising 20DP 14.5 PS involute cutters.

    https://www.ebay.com.au/itm/Lot-8pcs...53.m1438.l2649

    Cost is about $100 AUD and fortunately since I won't be in a hurry I won't have to worry about postage.

    I think I will buy these and have a go at making these gears.

    The existing gears are very hard, so can anyone suggest what grade steel I should buy to make them out. I am assuming some sort of hardening process will be required.

    Thanks

  9. #9
    Join Date
    Mar 2014
    Location
    South of Adelaide
    Posts
    1,225

    Default

    Use EN36A or 8620 for the gears and get it case hardened .020" deep. It wont move much during heat treat but you will need to finish the bore after heat treat to get a good fit.

  10. #10
    Join Date
    Aug 2008
    Location
    near Rockhampton
    Posts
    6,216

    Default

    I would also consider just make them out of plain 4140 and leave it as is. Looking at how they just snapped, makes me think they were too hard and brittle.
    Gold, the colour of choice for the discerning person.

  11. #11
    Join Date
    Mar 2014
    Location
    South of Adelaide
    Posts
    1,225

    Default

    Quote Originally Posted by .RC. View Post
    I would also consider just make them out of plain 4140 and leave it as is. Looking at how they just snapped, makes me think they were too hard and brittle.
    That's actually a pretty good idea. For hobby use a 4140 gear will probably outlast the operator.

  12. #12
    Join Date
    Mar 2011
    Location
    Taree NSW
    Posts
    119

    Default Beaver owner - needs advice

    Quote Originally Posted by pcx View Post
    Hi All,

    While doing some milling yesterday I noticed that the X axis feed on my Beavermill VBRP was slipping intermittently. It would drive for about half a revolution then slip then drive again.

    When I removed the feed gear box I found the following.


    How it was feeding at all I don't know.

    The gears are 20 and 24 tooth. I can't measure the small gear accurately due to the damage. The 24 tooth gear has a diameter of 1.3 inches.

    Despite much googling, I am unsure of the specifications of these gears. I think they are 20DP and 14.5 degrees PA, but I am not sure.

    I have been trying to find a company who may be able to supply the basic gears but have not found anyone listing 20DP.

    Can anyone help me to identify these gears and maybe suggest a source for them. I am thinking that the best way to handle this repair might be to turn off the old teeth and bore out some new gears and heat shrink them on to the original blanks.

    Alternatively I would be keen to buy a set of gear cutters and have a go at making them myself if anyone knows where they are available from.

    Thanks for any help you can provide.
    Hi pcx,
    great to find another Beaver owner - I am in Taree and as yet haven't run mine due to having to remake the coolant pump - I met a fellow a couple of weeks ago who said he used to work for Beaver in the U.K. - if you can't solve your problem I will chase him up and test his memory These mills must be thin on the ground here in Oz as I have only found one other owner on the forum and he is converting his to a cnc mill
    Alf Scotting

  13. #13
    Join Date
    May 2012
    Location
    Kimberley, West Australia
    Posts
    176

    Default

    Worth an email or a call to Hercus gears in Adelaide? They have an online catalogue of stock sizes, but can probably quote you to make new ones from your samples. Worth a try. Regards,
    Combustor.
    Old iron in the Outback, Kimberley WA.

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