goldfinder
starting to spend too much on rocks
Member since December 2020
Posts: 227
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Post by goldfinder on May 4, 2022 15:05:34 GMT -5
Hello all,
I've been in the process of building a wheeled cabber. I've been researching the DIY threads on here and they have been very helpful.
I bought a 1"x36" stainless rod on eBay that has LH and RH threads on each side and a keyed center section. Finally got some pillow block bearings that fit it right but found out the rod is definitely not very straight. When turning it there is an obvious bend, which will not let the wheels spin true and will definitely cause vibration. The bend was verified by rolling the rod on a flat surface. It clearly won't work for a lapidary machine where the wheels need to spinning true.
Does anyone have any source to get a rod/arbor suitable for a lapidary cabber? Basically any straight 1" rod with threaded ends would work. I've been searching high and low but nothing seems suitable. I wanted to build something that I could start with 6" wheels and eventually move up to 8" wheels as the 8" machines are quite pricey. But I'm starting to think I should have just bought a cabbing machine haha, lesson learned.
Any advice or suggestions would be great!
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Post by stardiamond on May 4, 2022 16:00:47 GMT -5
Machine shop. Unless you want to make large cabs, there isn't a huge benefit to an 8" machine. I started with a two wheel 8" machine, bought a Genie, retrofitted by 8" machine to 5 wheels. At the time I was a strong advocate for 8" machines because they were faster. I found that a 6" machine with an aggressive 80 grit wheel is just as fast. There are more good options for wheels now and the prices are better.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,341
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Post by quartz on May 5, 2022 0:02:38 GMT -5
If you have a press available big enough to handle the shaft parallel with the rails, and a dial indicator, put a v-block under each end of the shaft and push the high spot just a bit more than the runout, release and repeat 'till straight. It takes some practice but can be done, and it's not as hard as you might imagine.
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goldfinder
starting to spend too much on rocks
Member since December 2020
Posts: 227
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Post by goldfinder on May 5, 2022 14:33:21 GMT -5
Thank you both for the replies!
That is great info about straightening a rod in a press, I will definitely try that if I need to.
Luckily the eBay seller was very kind and offered to make a new rod and check it for straightness if I ship back the old rod. Fingers crossed the new one will be straighter.
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Post by Rockoonz on May 5, 2022 17:19:44 GMT -5
Was it sold as shafting or as a tension rod? Tension rod is generally low carbon construction grade steel. For an arbor you need decent shafting grade material that has been ground to tight tolerances. Kind of like this covington-engineering.com/equipment/grinders/steel-shaft-replacements/A machine shop would charge more for the labor, not counting the steel. It's pretty safe to assume that as soon as their stock runs out and they buy more rod to make them from the price will rise sharply.
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goldfinder
starting to spend too much on rocks
Member since December 2020
Posts: 227
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Post by goldfinder on May 6, 2022 13:26:04 GMT -5
Was it sold as shafting or as a tension rod? Tension rod is generally low carbon construction grade steel. For an arbor you need decent shafting grade material that has been ground to tight tolerances. Kind of like this covington-engineering.com/equipment/grinders/steel-shaft-replacements/A machine shop would charge more for the labor, not counting the steel. It's pretty safe to assume that as soon as their stock runs out and they buy more rod to make them from the price will rise sharply. It was sold as cold-rolled stainless steel shaft. The shaft and machining quality seemed good but there was a bend that got worse towards the threads on either end of the shaft. The center part was relatively straight and worked fine when I tested it running a 220-grit hard wheel on it. I'd guess the inner 18-20" was relatively straight but the outer 8" on each side has a slight bend and unusable for mounting wheels, that bend also lead to a vibration. I recently saw the Covington shafts you linked and I wish I would have gone that route to start with. If this next rod doesn't work out I'll probably order one of the Covington ones. Or just buy a bare 6-wheel arbor setup like the Lortone since I already have a new set of 6" JB wheels.
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