[balsaman]

What sort of backlash are you currently seeing?

Eric

What I have been doing is use a DTI and jog my machine incrementally untill I get it exact.

although even then I havent been cutting perfect circles, so what i did is adjust the backlash accordingly to cut them as perfect as possible. I will be sending my ballscrews and ballnuts to homeshopcnc(I think thats the site) to have them preload my nuts with larger balls for $35 each(that is me supplying the nuts and screws)

Jon

[JFettig]

Way too much. In my Y axis, I measured about .0065 but I have it set up around .008 for cutting perfect circles, the X axis is good though, .0015"meassured but set at .0025"
I have y z-axis preloaded so I dont have any problems there.(theres actually room there)

Jon

[ViperTX]

eric & jon, This is all valuable information that will certainly help the rest of us determine how to proceed. Do you both have the RF30 equivalent round column mill....I have a Jet JMD18 (RF30 equivalent) that I was considering CNCing.

[JFettig]

I have a sieg X2 mini mill from homier.com(they no longer have them)

If I had room for one of those RF30 equivalents I would have one

Jon

[balsaman]

I got lucky this weekend and found a used Plll 450 for $25.00 CAD. Installed XP and Mach2. Couldn't get my z axis working no-how until I finally changed the parallel port from bi-directional to ECP in the bios. Man, that Mach2 is nice software....I have been a turbocnc fan but I think I've been converted.

Eric

[JFettig]

oh wow does mach2 rock man.
I am upgrading my computer from a 700mhz celeron to a athlon xp 2500+ hoping to hit 200ipm

How many pulses does yours put out? my 700mhz system puts out 26000 for mach2, I installed mach2 on my server and it was putting out 46000, so I am hoping that I can do that with my mill

how fast are you able to get that thing moving?

Jon

[balsaman]

25 Khz max. My machine goes up to around 125 IPM which is scary fast. I have it set at 100 IPM which is 16.66 Khz. Mach2 is very slick. Smooth motion. The wizards are pretty cool too. The guy is a genius. I will be sending my money to Art shortly.

Eric

oh wow does mach2 rock man.
I am upgrading my computer from a 700mhz celeron to a athlon xp 2500+ hoping to hit 200ipm

How many pulses does yours put out? my 700mhz system puts out 26000 for mach2, I installed mach2 on my server and it was putting out 46000, so I am hoping that I can do that with my mill

how fast are you able to get that thing moving?

Jon

[FLUTE HEAD]

Hey balsa, I have similar machine fr. H.F. Did you find any slopp in the spindle sleeve when tramming. Mine has about 2-thous. slopp when locking the spindle sleeve. If so it would seem like the clamping piece thats included in the z conv. could fix this a bit.

[balsaman]

I have not measured the slop in the quill. I suppose there is some...

Eric

[balsaman]

I made some fixed hieght tooling. Started with 6, 1.5"x3.125" lengths of brakedie. Turned one end to .750, turned it around and put it in a 3/4" MT3 collet and turned the od as shown and bored for the various sizes endmills. I have one more to make and I need to drill and tap the set screws.

Next I plan on grinding a standard 3/4" R8 collet shorter so that the flange on the new tooling will be pulled up against the quill as the collet gets drawn into the taper. This way the tool z hieght should be repeatable between tool changes.

The plan is to make use of the tool length offset table in Mach 3.

Eric

[Stevie]

I don't think that will work; well not to within a few thou

[balsaman]

why?

[JFettig]

Balsaman, I made some similar ones like that a while ago and a few nicer ones now. The problem you run into is runout. when you bore them its not as much of a problem though.

You do need to machine them in a collet for sure but even then you run into runout.

The largest end mill you want to use in those is a 1/2" end mill, then for a 3/4" EM I made a little collar that acted the same that I use for that and bigger cutters so they are fixed.

Another thing you must do is grind a flat if there isnt one, if you dont, your set screw may gouge your end mills(hss) and in turn wreck your holders.

To make them press up gainst the noze of the spindle, you turn a little recess with a face grooving tool, I made mine out of a HSS blank and it worked good.



Jon

[Stevie]

forget it; I'm thinking like a tool and diemaker again; to me 2-4 thou is roughwork; sometimes I forget this is home stuff and they don't need to be dead on
I was thinking about my post while I was seting up the Y axis mount on the Gantry mill
and thought it will most likely be ok

[Stevie]

Hi Jon

I was thinking the same; and the height will be a bit of a problem too; but not as much as the runout

Me and a guy who works at the main plant (I manage a small grinding div) might be making a small cat taper holder range just for home use; maybe a 10 or 20 size

[balsaman]

ya, there will be a bit of runout. I did bore the larger ones and reamed the smaller ones. I do have flats on the endmills.

The z should be close because the flange of the holder will push against the spindle nose.

I'll measure the runout once they are in the spindle.

[kong]

Hi Eric, just wondering how hard is "brakedie"? I made a set of these for the router some time ago and they worked well. The only problem I found was that if you crash the tool, the toolholder becomes ruined. Mind you, I was using plain un-hardened silver steel for the holders. The thought of the steel warping during heat treatment always put me off of hardening them, you got any thoughts on this?

[Stevie]

Like any pre hardening process; you need to allow for movement during HT
I usually leave 0.01-0.005" for finishing after HT
If you use 4140 pre hard; you can use it in light duty stuff without any HT

I have HT myself many times with good success; the thing to remember is to quench in oil; never use water; the shock is too great and micro stresscracks will be started

A good O1 grade steel will give you good results

I've been a tool and diemaker for going on 37yrs (4 for the app/ship)
I'm allways open to questions

Drill rod; cheap and easy to find; will harden quite nice; you can use it right from HT without needing to draw it back a bit; or if you want to; just go light straw color and quench (water for draw quenches) you will still need to post machine to be dead on concentricity; but the movement will not be great; I've even had it swell; and ended up with more to remove from the diameter; but the length did lose some; the molecules had to come from somewhere LOL

[balsaman]

I think it's 4140 pre-heat treated. It's toughter than mild steel but was not problem to machine on my little lathe. Nice finish and chips when I took .080 to .100 of the od (max for my lathe), but not as nice on any finishing passes.

How did you ruin them in a crash? Did they bend?

Eric

[Stevie]

Eric

Punch the speed way up and it will finish nice with a 25-32 thou rad insert