You give no indication of how you intend to connect your four slabs. If this will involve welding, you need to take advice from your welder about how the edges to be joined should be shaped. You might find it helpful to do this before you spend further hours (and gears) removing metal which may not need to be cut away. And remember that once welded your slabs will not be exactly flat or parallel, so machining after welding will be better.

I am guessing about the welding but no clue is offered. If you intend to bolt the parts, it would only be needed for the areas in contact to be flat, saving time etc.

Cheers, Tim

How fast are your running your fly cutter?

At >6" diameter, say 20" circumference, and HSS cutting speed of 90 feet per minute you are looking at about 1 rpm. With a feed rate of 0.004" that's going to take you 25 minutes to clean up one inch of six-inch wide plate.

In other words, although you can probably get away with slightly faster rotation and feedrate for light finishing cuts you are still probably blunting the tool by working it far too fast, because you will go crazy trying to work it at a sensible speed.

You are better off using a multi-tooth milling cutter which you can feed much faster and take multiple passes.

Neil

Yep about 60rpm would be more like it, you would not turn 6" dia steel at 1rpm would you?

Infact a smaller flycutter swinging say a 2" dia would be quicker add less sensative to tram, 3 quick passes will cover the surface. Thats what I tend to use and prefer it to a multiple tipped tool for steel.

Edited By JasonB on 29/03/2016 20:06:46

I'm a silly s***, I was thinking one rotation per second!

Styill four minutes to feed an inch…

A tip you may find useful when fly cutting,if the facility exists on your machine, is to apply a small amount of friction to the spindle using the spindle brake whilst cutting. This ensures that the gears are always engaged and prevents them from bashing themselves to death. It usually eliminates the ripple finish sometimes experienced at the start of the cut. Roy M.

Why use steel? For a wood lathe aluminium would be plenty rigid enough. Why use a fly cutter? It might be quicker, more accurate and easier on the mill to use an end mill.

Cloth and rotating spindles are not a good combination. The traditional method is to take a piece of wood, say 1" x2" x 2 foot long and put one end up against the column of the machine and then let the side of the wood rub on the end part of the spindle or collet chuck, in a non-critical area. Apply gentle hand pressure to the wood, it does not take much to take up the "clunk clunk" back lash and make life much easier for the gears.

In less time than it would take to drive to the shop to get patio cleaner, you can take a 10" coarse file (bastard) and using one edge of it, ie with file canted at an angle instead of laid flat on the job, you can scrape that black mill scale off. You can even grind the end of the file into a slight angle to make a crude scraper for any tough spots.

Hi Iain,

Following comment is designed to be helpful:

Your machine has a 150W Brushed D.C. motor, with good torque, especially in the low gear setting. ARCs similar offering to a CMD10 is the SX1L, which has a longer table and bigger cast base. In the early days when ARC started selling these machine, an airline pilot friend of mine 'poo poo'ed' the mill, labelling it as the usual Chinese crap. He said: 'I bet you that this machine has no torque…it only has a 150W motor'. He was confusing AC with DC and he failed to take the low gearing into consideration. I put the machine in low gear and started running the machine at low speed. He decided to prove the point by trying to grab the spindle and stop it with his big hands. Initially, he failed. He had to put a lot more pressure, and reduce the speed to near zero, before he succeeded.

For H&S reasons, I cant possibly suggest that you try this Iain. The point I am making is that it has great torque, proportional to the size of the machine, but it is no mini-mill or Bridgeport.

After abuse occurs, broken gears etc., faults can/do creep through the electrics/motor, resulting in loss of torque in certain cases. Being a micro-mill, there is a limit to how much abuse the set-up can take, be it electrical or mechanical. Certain people try carrying out the above test after such gear breakage occur, to see how easy or difficult it is for them to stop the spindle in low gear by grabbing/putting force on it with their hands, at relatively low speed. If it stops easily, it would be a good indication of loss of torque due to damage/fault developing in the circuit board/motor.

Again, for H&S reasons, I cant possibly suggest that Iain or anyone else try this, and usual disclaimers apply to all of the above comments. Most of us are guilty of abusing our machines, but prevention is usually better than cure, which can be costly.

Ketan at ARC.

Iain,

Forgive me for asking … [the answer is presumably 'because I want to'] … but why are you making a Wood Lathe, using micro-size machinery ?

A quick look on ebay, etc. should find you a Record or similar lathe with a cast iron headstock. The detailing on these lathes is not good, but it would be much easier to 'improve' one than to start from scratch.

MichaelG.

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Edit: Here is an example … but they are often cheaper.

Edited By Michael Gilligan on 30/03/2016 12:29:29

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Good Man, Iain .. I look forward to the progress-report.

MichaelG.