Grizzly G0758 mill

[WobblyHand]

Maybe brush wear?

 

[dabear3428]

Someone help me here. Why would a brushed DC motor not like to run in reverse? Plenty do. Tons of battery powered tools for one. Also, my DC golf cart spends a lot of time in reverse.

The only thing I can think of is if the carbon brushes weren’t beveled in both directions… but are there brushes like that? (Honest question)
If so, couldn’t you simply pull the brushes and bevel the carbon yourself?

do not know for sure but i have read that the brushed dc motors are clocked for max forward power and are at a disadvantage in reverse.

I was told this is an issue and why mills like the g0758 do not come with a reversing switch. if that info is incorrect i would love to install a reversing switch in my g0758.

 

[Aaron_W]

i understand, the mill came into my possession as part of a package deal and wile it is not what i would have bought if i was going to grizzly i would have gone to the g0704 pm 30MV or the RCOG-25V for cheap, i'm just playing around with this hobby and will most likely move to something like a PM940M or maybe recondition a used bridgeport mill. right now i'm just figuring out how much time and money/time i want to play/spend in this hobby.

the g0758 was part of a package deal for an AXIOM AR8 pro+ in near mint condition for an absurdly low price. the mill and the router have been sitting in storage since the owner died and have some surface rust but almost no use,so like i said hard to pass on the package.

I'm looking into reversing the Z-axis slide to gain about 3" of Z travel has anyone done that?

I'm looking at playing around with installing a replacement motor maybe a BLDC so i can get reverse on the mill (my understanding is that brushed DC motors do not like running in reverse, anyone have any input on this?

long range i'm thinking that even with the CNC router (that can cut steel) and a larger mill it would be nice to have a small mill to work on small parts and like i said the price was right.

I have built a new shop 30X60 so room for multiple overlapping machines are not an issue (right now).

as everyone can probably tell I'm long on research and short on experience, cost is an issue but not an overriding one, so any ideas from more experienced people is appreciated.

Ok, big difference between thinking of buying this mill, this is the mill I have. I assumed you were shopping.

I'm not familiar with that particular mill beyond looking up the specs. My little mill is a Sherline so an entirely different creature other than understanding some common issues with little mills.

There are tricks you can use to work around the height limitations, but they cost money. You can buy screw machine drill bits which are shorter in length than the common jobber drill bits. They also make some "vises" which are basically jaws mounted directly to the table, eliminating the base of the vise, buying an inch or so.

In your case, probably best to use the mill and see how it does for the work you want. Hobby machining can be a huge money pit.

If you are finding the mill is fairly satisfactory for the projects you want to do, then it may be worth investing more time and money into it.
If not, use it to learn with, figure out your needs and start looking for something of a more appropriate size for your needs.
Small mills are popular, so if you find it lacking for your needs, you should have no trouble flipping it.

 

[dabear3428]

Ok, big difference between thinking of buying this mill, this is the mill I have. I assumed you were shopping.

I'm not familiar with that particular mill beyond looking up the specs. My little mill is a Sherline so an entirely different creature other than understanding some common issues with little mills.

There are tricks you can use to work around the height limitations, but they cost money. You can buy screw machine drill bits which are shorter in length than the common jobber drill bits. They also make some "vises" which are basically jaws mounted directly to the table, eliminating the base of the vise, buying an inch or so.

In your case, probably best to use the mill and see how it does for the work you want. Hobby machining can be a huge money pit.

If you are finding the mill is fairly satisfactory for the projects you want to do, then it may be worth investing more time and money into it.
If not, use it to learn with, figure out your needs and start looking for something of a more appropriate size for your needs.
Small mills are popular, so if you find it lacking for your needs, you should have no trouble flipping it.

yes i agree with all you have said, right now just having fun tinkering with it and seeing what i need to do differently (if anything), anyway i am very interested in different opinions about this mill, i just learned that Custom Crafter makes a kit to put a 750 watt servo on this type of mill for a good price, so im learning something new every day.
thanks for the insight.

 

[BGHansen]

+1 on getting the biggest machine that space/budget allows. Here's a decent looking Enco square column mill on Craig's List.

Bruce

Enco mill drill machine - tools - by owner - sale

Enco milling drill machine 20" square column 22"x8" travel. R8 spindle 220v single phase 2hp. Includes some tooling, collets, vise. Approximate weight 700lbs. $1500 obo

dallas.craigslist.org

 

[RaisedByWolves]

yea i hear you, was looking at the PM25 mv also, i was leaning toward the cheap RCOG-25V as my starter mill but then this fell into my lap.
over all i kind of like this small mill and will probably spend more time/money upgrading it than making stuff with it. working on installing cheap glass scales on it now so i can fit a touchDRO or even just a cheap 3 axis dro, anyone have experience with putting scales on these small mills?

BTW my wife thinks i'm crazy, the sad part is i agree with her lol

I’m getting to mounting glass scales on a similar sized machine.

It’s a little different than a traditional setup but nothing terrible.

Prazi BFE65-Littlemachineshop Big Mill table Frankenbuild, spin off thread.

This thread is a spin off of the following to keep things from becoming cluttered. Lathe Mill score thread. I got this mill head in a package deal as posted in the above thread but the milling table/base was not included. Having read everything I could find about this combo and working as a...

www.hobby-machinist.com

Not quite there yet but I’ll post pick when it’s installed.

Here’s a video of a bad install to keep you busy.

My install is similar. But I mounted my X scale so it does not take up half of the Y travel.

No idea what they were thinking here.

 

[dabear3428]

+1 on getting the biggest machine that space/budget allows. Here's a decent looking Enco square column mill on Craig's List.

Bruce

Enco mill drill machine - tools - by owner - sale

Enco milling drill machine 20" square column 22"x8" travel. R8 spindle 220v single phase 2hp. Includes some tooling, collets, vise. Approximate weight 700lbs. $1500 obo

dallas.craigslist.org

View attachment 455967

nice but not there yet, i have been watching several in my area but the timing is not right yet

 

[dabear3428]

ok so operation g0758 max headroom is a success, i turned my z axis slide over no new parts and my max spindle to table went from 8-3/4" to 14" maxed out and partially unsupported ways, but 11" with fully supported ways. no permanent modifications and it would take 1hr to reverse.
best part was it was free.

 

[dabear3428]

Some photos, l know l know no photos and it did not happen

 

[RaisedByWolves]

Some photos, l know l know no photos and it did not happen

Only quibble I have with that is that now your gib is on the opposite side of what it was designed for.

If there was any thought put into this at the engineering stage(total crap shoot there) this might put more cutting forces on the gib screws and make maintaining the gib adjustment more difficult.

You are increasing the leverage on the ways with the quill that much further away, but will it ever matter?

Maybe over the course of 20 yrs use or so.

Have you trammed the head on this yet?