pfred1 said:

 Viper7926 said:

Well for everyone who has encouraged me to get some manual machine time in before embarking on CNC, the Gods have intervened.  A "new" Grizzly 3358 (non CNC) followed me home tonight and now is resting peacefully in my garage on a trailer waiting to be taken to it's new home in my shop.  Caught an ad on Craigslist where I have been faithfully searching every day, and sometimes twice a day, perusing the offerings of  CNC mills.  It was such an attractive deal I couldn't pass it up so I called the fellow up today and just picked it up.  So now I'm committed to following every one's advice and will begin to learn the fundamentals.  It will be nice to have a machine to come home to when I get into the Intro to Machine Shop course at the local  junior college.  So thanks again everyone

 

I have a similar bench top mill from Horrible Fright. I got mine as a scratch and dent off HF. As I can recall the ad said some slight surface rust, or something to that effect. I noticed a welded repair in the T slot table on mine. Not sure how that figures into it all. It is a heck of a drill press, struggles a bit milling mild steel though. I find getting as close as I can to it's resonant sweet spot with surface speed helps me a lot. On my mill that is around 100-125 SFPM. Using chainsaw bar lube as way oil has helped out somewhat too. Maybe I just haven't found the right cutting fluid yet? Could be the stand I have mine on too. In any event getting my mill to work with mild steel is a bit difficult. I don't expect anything more than light cuts out of it.

 

I've worked in a machine shop running real machines and there is no comparison. So you may notice some differences between the machines you get to use in class and your machine at home.

 

 

My stand is made out of 3 inch C channel steel legs with a welded 3x5 inch heavyweight angle (over 3/8s thick) frame top. The machine is bolted to the top frame. It all seemed heavy enough to me when I made it but now I'm thinking about pouring a cast concrete base. I might just box in the stand it is on now and slush it with concrete. Hate to lose my drawer though … Quite frankly I doubt it'd help much which is likely why I haven't done it yet.

 

But the thought has still crossed my mind a few times. As heavy as these mills seem to be when you move them they're still not quite heavy enough. The columns on them are probably too weak. Before I reinforce the base I might just try to do something about the upright column. I'm pretty sure it is hollow. That might have to change someday on my chatter box.

 

Don't take anything I've said as an indictment of the machine, just relaying what I've noticed over the course of owning mine. Did I say it is a heck of a drill press? That is mostly what I use mine for anyways. I find halving the surface speed I mill at to be the best for me boring. I'm not sure if that is normal or not?

 

My hot tip, if I have any, is to keep a notebook in your shop where you record speeds and feeds you use with various materials and tools and evaluations of their success and failure. Often I write the speed I run a tool at for steel on the tool's holder. Saves me time recalculating the speed, or having to look it up. One more thing, I'm not entirely sure of the accuracy of the speed chart these machines come with. I haven't put a tach onto my machine yet but just doing some rough calculations of the measured pulley sizes shows up some ah shall I say discrepancies? So it might be best to take the speed chart with a grain of salt and use them as ball park figures. then again they could be dead on too, like I said I haven't tached my machine yet, just did the math on the motor speed and the pulley sizes. Things just didn't add up exactly. Though if memory serves the error was linear so maybe they figured it for 50Hz operation or something? I don't know. I guess what I'm trying to say is when you're milling steel the speed is pretty critical so I've gone through a bit of trouble to determine the best ones here. Softer metals like brass or aluminum not so much. Steel is the metal that tests these machines.

 

What these machines cost to buy initially is but a small fraction of the total tooling and instrument investment. I hope yours came with something.

Concerning the problems that you have with your column,I have to say I have'nt tried what I'm proposing,but if anyone out there has,I'd be very interested to know their results.Vibration and machine tools don't mix well.How to get rid of the vibration?.Commercial practice is to fit either shock absorbers,or fit dampers of some kind,usually rubber(motor mounts etc.)What I thought was that if the column was filled with dry sand,and sealed off,the sand would add some extra mass,but also act as a damper,and dissipate the vibration.If it works,this would be a good,cheap quick solution.Any thoughts that forum members have on this solution would be welcomed.

pfred1 said:

Oh if I were to fill it it wouldn't be with dry sand. More like a lot of re-bar and enhanced concrete.

Was looking at a plan recently,from an old magazine,can't remember the

title,Was a build it your self horizontal bench  mill,the body of the mill was made of concrete…………..

pfred1 said:

I think I'd like to get a more capable machine. Within its limits my imported mill does work.

Still merans more concrete Fred…….lol………..