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tbone
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« on: February 28, 2011, 11:28:12 AM » |
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I finally got round to looking at this Drummond lathe.
I plan on fitting a countershaft to run at approx 300rpm, so i have been looking at the headstock speed and i`m confused!
I have an electric motor running at 1490 rpm, when i attach the belt directly onto any of the 3 pulley`s on the headstock, I get 3 very low speeds, 91, 115 and 156 rpm. I should be getting 3 extremly fast speeds of over 1000rpm.
Now, the only thing i can assume is that i am losing speed through the 2 back gears on the shaft behind the headstock.
Although this shaft disengages, without it engaged, the headstock does not turn, so i assume it has to stay engaged?
With the back gears disengaged, the pulleys turn and spin free on the headstock shaft, so is my problem at the right side of the pulley cone, should the bull gear be attached to the pulley cone?
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« Last Edit: February 28, 2011, 11:49:57 AM by tbone »
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NO I WON`T. aye ok then, i will
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tbone
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« Reply #1 on: February 28, 2011, 11:59:21 AM » |
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I think i just answered my own question! i`m off to look at the bull gear  |
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NO I WON`T. aye ok then, i will
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Manky Monkey
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« Reply #2 on: February 28, 2011, 03:42:18 PM » |
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I have absolutely no idea what you're talking about.  |
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On the last freedom moped out of Nowhere City.
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tbone
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« Reply #3 on: February 28, 2011, 05:29:11 PM » |
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I don`t think i do either.......but it sounds good  . Yep, sorted it. The bolt on the bull gear wasn`t engaging the cone....it kept slipping past it. Slackened everything off, tapped the gear back along the shaft, re-tightened and hey presto! running at full speed. Next job is to do a few calculations to sort out the pulley sizes, then make the countershaft. |
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NO I WON`T. aye ok then, i will
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TwistedPatience
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« Reply #4 on: February 28, 2011, 08:33:45 PM » |
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TB dont engage the back gears they will slow it down, that's what they are there for.
Do you have a countershaft now?
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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tbone
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« Reply #5 on: March 01, 2011, 08:48:17 AM » |
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Cheers mate . Not got a countershaft yet, I have sat and worked out various combinations of pulley sizes though. I know the norm is to use a match for the headstock cone and reverse it, but i`m unlikely to pick up another cone the same, so..... If i drive the countershaft with an 11" pulley, i get a tad over 300rpm (307.48 to be precise and anal!), using a 2,3,4 & 5 inch stepped pulley on the shaft will give me a range between 136rpm lowest speed and 645rpm top speed. If i add a 6" pulley, i`ll get 775 rpm top speed I dont think the old girl should exceed 800rpm and with the back gearing in place i should be able to come to an almost complete stop  |
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NO I WON`T. aye ok then, i will
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TwistedPatience
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« Reply #6 on: March 03, 2011, 12:53:07 PM » |
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TB you can get new pulleys from http://www.abcpolishing.co.uk/ including the stepped 3 speed and also bearing blocks. |
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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tbone
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« Reply #7 on: March 06, 2011, 12:06:13 PM » |
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Thanks for the link Doc. I`ve just finished welding together a stand to sit behind the lathe to mount a shaft onto, got a fella who says he has a Boxford shaft somewhere, mine for £15 if he finds it!
A bit of research shows the Boxford used a 6" pulley to drive the shaft so i need to redo my calculations, should be ok, just means the counter will be turning at twice the speed i`d originaly planned on.
Did you ever sort out a quick change toolpost? I have looked at the universal type but think i would need to grind down the height of the tools to around 5mm to keep them central to the workpiece, then i would still have to shim at the top to hold them in the holder.
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NO I WON`T. aye ok then, i will
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TwistedPatience
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« Reply #8 on: March 07, 2011, 12:52:01 PM » |
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Trikertim001 I'm not using a QCT on mine as I am going to keep it original (ish).
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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tbone
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« Reply #9 on: March 08, 2011, 07:52:52 AM » |
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Well spotted! Not that it was any help. |
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NO I WON`T. aye ok then, i will
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TwistedPatience
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« Reply #10 on: March 08, 2011, 08:22:09 AM » |
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Haha not like here on MMM eh!
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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tbone
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« Reply #11 on: March 08, 2011, 11:40:59 AM » |
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Very true! If i overhang the tool holder, down the side of the top slide, do you think i`ll get excessive chatter? I`m not sure how tight the toolholders fit to the main block and all the ones seem to be above/on the top slide. I presume that as these devices are height adjustable, it will not matter if the bottom of the tool holder is not rested on anything? There is an `unknown` top slide on ebay at the moment, looks like it would fit ours, with a bit of shaving to the sides of the platform i think i could get a qcp on it |
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NO I WON`T. aye ok then, i will
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TwistedPatience
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Teetering on the edge of insanity
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« Reply #12 on: March 08, 2011, 01:21:10 PM » |
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You presume right TB. The only way you going to find out if there is too much chatter is to try it.
I have a 4 way tool post I was going to fit but the main bolt on the topslide is way too big so I'm not going to bother.
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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tbone
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« Reply #13 on: March 11, 2011, 10:44:22 AM » |
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I wish i could keep track of all the crap valuable items in my shed! I pulled one of the villiers engines off the `need looking at` shelf and found it`s fitted with a 3 step pulley! so i had one all the time . Ah well, i`m waiting on the boxford one to arrive now so i guess i`ll be spoilt for choice |
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NO I WON`T. aye ok then, i will
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TwistedPatience
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Teetering on the edge of insanity
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« Reply #14 on: March 11, 2011, 11:08:23 AM » |
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Don't take it off use the villiers engine to power the lathe, now that would be novel.
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"It's time to raise the Finger,
That middle digit takes your point and drives it home"
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