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a Used Bridgeport milling machine
jmelson:
I had an ancient round-ram manual Bridgeport mill that a friend and I bought in 1982. In 2007 I converted it to CNC, but it was quite a hack job. Last year, a friend had a Bridgeport R2E3 that needed a control retrofit that he let me have for scrap price. I did a control retrofit to LinuxCNC using AMC servo amps from eBay. The R2E3 was in WAAAY better shape than my old machine, which had quite measurable wear on the ways. But, I am a LinuxCNC developer, and make CNC retrofit equipment for this market. So, I can be considered an expert.
Jon
thm_w:
--- Quote from: beanflying on October 14, 2023, 12:56:49 am ---If you watch enough Blondihacks videos (you should because overall they are great) you will know her older mill and even the newer one run into rigidity issues when she tries to push to hard.
--- End quote ---
Yes but you are not "pushing hard" when you are working on a 1" part made of teflon or aluminum. Which is what the OP is intending on using it for.
--- Quote ---While high speed (10-20k toy/hobby) fixed ratio spindles might be great at screaming tiny carbide bits into material they are not remotely useful for material removal in metal and even plastics and timber will suffer needing far more passes (time) to even look at getting a job done. Add to this the lighter gantry or stand they are typically attached to and you are going to find using it above watchmaking/small stuff painful.
--- End quote ---
No toy hobby spindles are not appropriate, but, 10-20krpm as a spindle top end is entirely appropriate for the small designs mentioned. Small stuff is the intended purpose.
beanflying:
There is no right or wrong with spindle speeds and machine rigidity there just needs to be a basic idea of what the compromises are and some of the downside effects.
The OP started off talking about a Bridgeport/clone then went on to explain 'a' current use. There is a vast gap between this one need and the capabilities but it is very reasonable to consider that most people with our sorts of toys and a vast arena of other interests that Steel and or larger projects might come up. Why else would you consider Freighting a monster when $1k and about 100kg of lightweight mill/drill would do?
A geared spindle that can get into the area of 3-4k is still ok for smaller Carbide tools but also then gives you much heavier options including tapping all the way into tool steels because you can run it slow. While you can 'sort of' work in steel with tiny carbide at 5-20k+ driving one manually would send you nuts due to snail like pace of any real operations. While there are plenty of industrial solutions that get around some of this they are more like $50k++ and are way off scope for this topic (Go watch some Adam the Machinist videos for one of those options 8) https://www.youtube.com/@adamthemachinist/videos )
thm_w:
--- Quote from: beanflying on October 17, 2023, 01:13:01 am --- Why else would you consider Freighting a monster when $1k and about 100kg of lightweight mill/drill would do?
--- End quote ---
They specifically said they work on sensors, small items.
OP probably has no clue about other options.
$1k would not really be enough here.
beanflying:
Even locally we have a plenty in just over and just under $1k. The BV20LV as an example is still a better buy over its little brother. Really not that rigid but it will do steel slowly. The table travel (220x160x210) on the sub $1k model is really limiting so not even close to a good idea unless you want to stay with tiny stuff only.
https://www.machineryhouse.com.au/m650
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