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23rd Apr 2019, 11:20 PM #1Member
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24th Apr 2019, 12:03 AM #2Golden Member
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24th Apr 2019, 09:06 PM #3Member
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25th Apr 2019, 12:10 AM #4
Waldown NH B set pulleys
Hi Matt,
RayG has an NH drill with ONLY the B set of pulleys. He hasn't been active here for a while, but send him a PM. I'm sure he could help you with dimensions.Cheers, Joe
retired - less energy, more time to contemplate projects and more shed time....
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25th Apr 2019, 10:01 AM #5Member
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25th Apr 2019, 12:40 PM #6
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25th Apr 2019, 02:16 PM #7Member
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25th Apr 2019, 11:10 PM #8Golden Member
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26th Apr 2019, 01:29 AM #9Member
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26th Apr 2019, 11:18 AM #10
The original thread is here... //metalworkforums.com/f65/t175815-waldown-speed the pulley dimensions I have are for the 12000/6000 rpm speeds. Note that it's not 20,000 NH model B as in the Brobo catalogue
The front measures 1 1/2" and 2 3/4 the motor pulley measures 6" so that's motor_rpm * 4, and motor_rpm * 2.18 So if the motor is 2880, that's 11,520 and 6,278...
The motor pulley flips upside down to get the other ratio.
However, this model doesn't appear to be the same speeds as the NH model, a similar unit is shown in McPherson's catalogue, the V85 model but that's a 6 speed. So the long story short, if you are chasing 20,000 rpm you would need to crank up the motor with a VFD to get there, or machine the front pulley to a smaller diameter. Mine only goes to 12,000 with this pulley set.
If you changed the smaller diameter to 0.869" instead of 1.5" that would give a ratio of 6/0.869= 6.94, 6.94*2880 = 20,000
DSCN3406s.JPGDSCN3405s.JPGMcP-1955-WaldownV85.jpg
See earlier thread here
//metalworkforums.com/f65/t1758...93#post1691893
Hope that helps.
Regards
Ray
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26th Apr 2019, 12:55 PM #11Philomath in training
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Nice to here from you again Ray.
I did a bit of playing on Excel with respect to the ratios I have (3k to 12k) and what the corresponding ratios for 15k and 18k would be. The minimum for the spindle pulley seems to be around 34mm. Based on that for 18k, a motor pulley of around 206mm would be needed. That of course means a new belt as the existing has a belt of a length for the same size smaller pulley and a smaller motor pulley too. I don't have the time now but could possibly try and calculate out what the pulley sizes for the same size belt would be.
Having said that, do you really need 18k rpm? That is not a very big drill bit in anyone's language...
Michael
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26th Apr 2019, 05:12 PM #12
Hi Michael,
Good to drop back for a visit. Still busy and too many unfinished projects. I'm not the one looking for higher speeds, that's mattm82.
But since you asked, there appears to be plenty of room for belt length adjustment. There must be a minimum diameter for that flat belt material however, that might ultimately be the limiting factor.
If it was me doing it, I'd probably go with a variable speed drive, those motors usually run quite happily at 100 Hz. That would get 24,000 + rpm
After all those considerations it ultimately depends on the part being made, sometimes it's easier to drill small sizes in the lathe with the drill bit mounted in the tool holder.
If you follow Stefan Gotteswinter on Youtube he does a lot of drilling small holes in parts using that method. https://www.youtube.com/channel/UCY8...s38bR9X061jFWw
Ray
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27th Apr 2019, 10:38 AM #13Member
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Ray,
Thank you for your reply. I do have the higher speed machine, so I’ll have to look at your your calculations, along with how it matches up to my machine.
I have a single phase model and would like to keep it intact so a vfd is not an option.
To answer Michael’s question. I don’t need those speeds, I just want to have a complete system.
I use it a lot, but have another two Waldowns, have likely acquired another, and have some waldown vices to go with them. I love these drills so it’s more a want than a need!
Thanks again for your assistance.
Matt
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