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Project Logs / Re: Steady for Harrison
« Last post by shipto on Today at 02:51:33 PM »
The brass is fitted and allows around 28mm of movement although that might increase because I forgot to flatten the bottoms. I will get that done and clean them up for blackening over this long weekend.
Sorry for the dark picture will try for a better one.
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Tools / Re: Measuring backlash on rotary table
« Last post by philf on March 27, 2024, 01:42:50 AM »
Another possible problem is that the backlash could vary over the 360 degree movement. In that case I doubt backlash compensation would be much use. As Muzzerboy has suggested have you tried to adjust the meshing of the worm and wheel to reduce the backlash to a minimum?
[On my Vertex dividing head it's impossible to get rid of backlash. The wheel must be slightly eccentric as trying to minimise the backlash at one point will mean it can lock solid at another]
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Project Logs / Re: Steady for Harrison
« Last post by shipto on March 26, 2024, 03:28:20 PM »
Bit more progress, made some knurled nuts which I had intended to add some slots for a C spanner but I really hope they are not needed because that knurling has come out really well.
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Tools / Re: Measuring backlash on rotary table
« Last post by Muzzerboy on March 26, 2024, 01:21:24 PM »
Can you not adjust out (or at least reduce) that backlash? Many / most rotary tables have an eccentric adjuster on the wormwheel for this purpose.

Backlash adjustment in software assumes the table is driven against a friction-like drag load that resists angular movement but you may well have a machining load that biases the wormwheel in the other direction, in which case the anti-backlash may actually double the error when you change the direction of movement.

To measure the angular error, perhaps you would want to lock the table and then apply a controlled torque to the wormwheel in each direction. It's not a perfect science, since there is inevitably a degree of spring so that the backlash will depend on the torque you apply. If you applied no torque but simply moved the wormwheel in alternate directions, you'd get a smaller backlash - but not necessarily what you will see with a real world load applied.....
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Tools / Measuring backlash on rotary table
« Last post by Dell on March 26, 2024, 07:26:56 AM »
am motorising my rotary table using stepper motor and World of ward’s controller and it has backlash compensation in the settings but how do I measure it , on the handle vernier it’s just over 1 and a 1/2 notches but that’s not very accurate is it so I would like to be more precise .
Dell
https://www.worldofward.com/
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Project Logs / Re: Steady for Harrison
« Last post by shipto on March 24, 2024, 09:22:51 AM »
Decided against making the end nuts do double duty and have knocked up 3 7/8UNEF grub screws instead. pic makes them look much worse than they are but I really should have faced them after parting them off but its not like I'm going to give them anyone else.
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Project Logs / Re: Steady for Harrison
« Last post by shipto on March 23, 2024, 01:34:28 PM »
Spacers are made and with them in the way shown it will take about 65mm bar. I may need to make some half size spacers but need to get hold of more tube for that as I just about had enough for these.
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Project Logs / Re: Steady for Harrison
« Last post by shipto on March 23, 2024, 08:23:39 AM »
Progress so far: I have made the brass holders and all thats left to do on them is to bore the end once I have the brass which I forgot to pick up on friday  :doh: then work out how I make the adjusters. I am thinking that the end caps might do double duty but not decided yet.
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Our Shop / Re: My cubbyhole
« Last post by vtsteam on March 22, 2024, 03:14:38 PM »
Nice!  :thumbup: :thumbup: :beer:
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Our Shop / Re: out with the old in with the new
« Last post by vtsteam on March 22, 2024, 03:03:55 PM »
The shop looks great, Bob!  :thumbup: :thumbup: :clap: I don't blame you re. waiting for good weather. Same here..... :beer:
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