Hi guys,
I’m planning to build my first frame and am looking at arbors on the Paragon Machine Works website. My uninformed feeling is that the 2 1/2 arbor is too short and the 7 1/4 arbor is too long.
Could someone tell me what you use and why?
Thanks so much!
Most of the Arbors used in our shop are 2 1/2. We do have a few 7 1/2 full length and some cut down to 4 ish for big angles or cuts that have to be done in one of the vertical mills. It is worth noting that every mill that has an arbor used in it also has an ER collet adapter which adds a few inches of length to the spindle.
I do any machine notching either on a lathe with a v-block tool post, or in a home made ‘vogeltanz’ style “c-t-c” notcher, powered by a hand drill… and both of those situations can call for a good long arbour, but also wont be limited or made more difficuilt by an arbour being “too long”, I only have one and its about 400mm long…
I also seem to design my way into a corner with some regularity where I need to cut a tight angle mitre thats really long, sometimes like 5-6"
I imagine people who notch using a holesaw in a vertical mill, (especially a smaller vertical mill) are possibly quite constrained on tool height above the table; once there’s a vice and sometimes a fixture holding the tubes up off the table, for example a chain-stay fixture, and a collet chuck on the end of the spindle, having a nice short arbor makes the setup not just stiffer, but also actually possible; given the excess length of a longer arbour may not slide freely up into the spindle, like it would through a lathe’s spindle bore.
Thank you Neuhaus_Metalworks and crowe-molybdenum! That’s very good information!
What’s the reasoning behind this?
It probably makes sense to do this in your horizontal mill that has a Brown and Sharpe taper due to that taper’s obscurity and the relative lack of available tool holders, but why put the ER collet adapter in a Bridgeport clone that has an R8 taper? Are you using an arbor that’s more than 1" in diameter?
What’s the reasoning behind anything we do?
It’s easier to change and every machine uses the same collets. There are more people than just me that work in this shop, the fewer opportunities for the wrong part to be used on the wrong machine the better.
I also have bad shoulders and a habit of breaking ribs; I try to keep all work mid chest level. No need to make things harder on myself.