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Need advice, G0757 vs G0796

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grantj

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#1
Hi all,
I need some help deciding between the G0757 and G0796.

G0757 g0757.jpg
http://www.grizzly.com/products/Variable-Speed-Horizontal-Vertical-Mill-with-DRO/G0757Z

G0796 g0796.jpg
http://www.grizzly.com/products/9-X-49-Vertical-Mill-with-Power-Feed-and-DRO/G0796


G0796 is essentially a Bridgeport style mill. Similar features and capabilities as everyone is used to seeing.


The G0757 is a knee mill with the addition of horizontal milling (run off a separate 2HP motor).
I am hobby machinist and occasionally I make parts for my day job, in hopes that the hobby will pay for itself. We make customized equipment, so some of the parts we use are all very similar, but different enough that it would be worthwhile to make some blanks and then modify them myself as needed.

The main part I'm looking at making is typically 24" long and has some type of grooved shape in it, similar to the attached image. I think this would be perfect for a horizontal mill. I'd be able to get a lot of the material removed in a single pass, instead of picking away at it with a long, small diameter end mill.
ex1.jpg


My concerns for it are:
No powered quill feed.

The damn table ROTATES. Pretty cool for the horizontal milling, but, I'd rather swivel the vise. But I worry how much of a pain is going to be to get trammed. Will this be a weak link that works loose and allows for chatter? I'm not familiar with this feature at all, and I wonder if it does more bad than good.

The table travel is only 23.5". I already plan to use a pair of matched vises on the table to hold the long parts, but now, I'd be looking at having to set it up and move the part for every cut. I'm not sure I'm skilled enough to carry on a cut after moving the vise without it being obvious.

I'm also not as keen on the max 2300 RPM spindle, but both mills are similar. So unless I added VFD, I'm stuck in that range anyways.

I have no tooling for horizontal milling and no experience with it.

I'm coming from using a Rong Fu 45 style mill and decided that I'm spending enough time in front of my mill and have enough room in my garage, that a full size knee mill would be worth while.

Any advice would be much appreciated.
 

Dabbler

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#4
Grantj, for what it is worth, there never seems to be enough real estate on the mill table. I used an 8X30 Mill for years ( it actually had 31" clamping and 22" travel) and I was always fighting to mount even what seemed to be small jobs.

What really matters is quality of the spindle, lead screws and way squareness. Without that, you don't have a mill. After that, having a large table is very convenient for setting up any job. I've know a bunch of machinists, and it has none of them have ever lamented not having a swivel table.

I upgraded to a 9X49" First Bridgeport clone with DRO. The table seems big enough, but all my friends (but 0ne) bought 10X50 mills. We all work on firearm receivers (which seem quite small) and the like, and by the time you put a rotary table and and tail stock, even a 49" table can seem a little crammed.

Oh - and you will find a DRO will be a godsend. Once you have it, you'll wonder how you ever used a machine without it; even for straightforward slotting jobs like your picture... A DRO on a mill is what I consider essential equipment, but on a lathe it is (in my opinion) a luxury.

Just some thoughts from a guy who bought the wrong machine first, then found the right one.
 

lcrepairs

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#5
Hi all,
I need some help deciding between the G0757 and G0796.

G0757 View attachment 229015
http://www.grizzly.com/products/Variable-Speed-Horizontal-Vertical-Mill-with-DRO/G0757Z

G0796 View attachment 229016
http://www.grizzly.com/products/9-X-49-Vertical-Mill-with-Power-Feed-and-DRO/G0796


G0796 is essentially a Bridgeport style mill. Similar features and capabilities as everyone is used to seeing.


The G0757 is a knee mill with the addition of horizontal milling (run off a separate 2HP motor).
I am hobby machinist and occasionally I make parts for my day job, in hopes that the hobby will pay for itself. We make customized equipment, so some of the parts we use are all very similar, but different enough that it would be worthwhile to make some blanks and then modify them myself as needed.

The main part I'm looking at making is typically 24" long and has some type of grooved shape in it, similar to the attached image. I think this would be perfect for a horizontal mill. I'd be able to get a lot of the material removed in a single pass, instead of picking away at it with a long, small diameter end mill.
View attachment 229014


My concerns for it are:
No powered quill feed.

The damn table ROTATES. Pretty cool for the horizontal milling, but, I'd rather swivel the vise. But I worry how much of a pain is going to be to get trammed. Will this be a weak link that works loose and allows for chatter? I'm not familiar with this feature at all, and I wonder if it does more bad than good.

The table travel is only 23.5". I already plan to use a pair of matched vises on the table to hold the long parts, but now, I'd be looking at having to set it up and move the part for every cut. I'm not sure I'm skilled enough to carry on a cut after moving the vise without it being obvious.

I'm also not as keen on the max 2300 RPM spindle, but both mills are similar. So unless I added VFD, I'm stuck in that range anyways.

I have no tooling for horizontal milling and no experience with it.

I'm coming from using a Rong Fu 45 style mill and decided that I'm spending enough time in front of my mill and have enough room in my garage, that a full size knee mill would be worth while.

Any advice would be much appreciated.
I was debating between those two mills myself. I would love to have a Horizontal/vertical but not having DRO was the deal breaker for me. As a very inexperienced hobby machinist It's too confusing for me during jobs chasing/remembering backlash and can very easily scrap parts. I ordered the G0796 but it's on backorder until FEB or MAR
 

jcp

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#6
At the job shop I retired from we had a #3 Summit universal mill. It's a larger brother to the 757 you're looking at. I can only remember swiveling the table twice in 20+ years. We set it up as a vertical initially but it was somewhat limited in spindle RPM. Later it was set up as a horizontal mostly as we did a lot of large keyed shafting. Can't beat a horizontal for that.
Moving a part on the table can be overcome with some jig blocks fairly easy (part clamped to table, no vise).
 

Silverbullet

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#7
I've always said I'd rather have it and not need it . So I'd pick the combo mill.. Dro can be added anytime. Many of the very old horizontal mills had the table rotation built in . Don't think it would be anymore trouble than any other mill to tram . Table first then vise or whatever.
 

lcrepairs

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#8
At the job shop I retired from we had a #3 Summit universal mill. It's a larger brother to the 757 you're looking at. I can only remember swiveling the table twice in 20+ years. We set it up as a vertical initially but it was somewhat limited in spindle RPM. Later it was set up as a horizontal mostly as we did a lot of large keyed shafting. Can't beat a horizontal for that.
Moving a part on the table can be overcome with some jig blocks fairly easy (part clamped to table, no vise).
I Agree, I love the Horizontal option, however, It seems like that one had less table travel than the other. I'm limited here to single phase, so that narrows my options. As for DRO that seems like something that is so expensive and time consuming that one would never get around to it. I sure want to add quill DRO and Y & Z power feeds and maybe a riser block and power draw bar. Would love to know the part numbers or specs on some of those items for the G0796. Thanks to all that can share info on this specific mill.
 

qualitymachinetools

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#9
I personally do not care for that horizontal/vertical mill, they work OK, but the quality is not the best at that price, its 100% China. You made the right choice with just a vertical knee mill. Can always get the horizontal attachment if you need it, although not quite the same. When you are up in that price range, you can get a better machine in my opinion. Others may love the machine. We carried it at one point years ago. It was OK.

I don't want to come on here and try to sell anything, so will only mention it once, but we have the PM-950V mills on the way in, we will have them in Feb 100% for sure. Ends up being less money that that G0796, variable speed head instead of step and our head is made in Taiwan, single phase, and 3 axis DRO instead of 2. Our price will be going up too after this shipment sells out, the price increases from the factories are huge right now, but they are still at $5999 while we still have some left on this next shipment. Its on the water, its a sure date. Ship name is OOCL CHONGQING V.021E Wont say anymore about this here, don't want to steal the thread.
 

grantj

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#10
Didn't realize this was still getting attention.

I did end up going the PM949TS (Bridgeport clone) and I have been extremely happy with it. I've added a cheap import DRO, power feed, and VFD for variable speed.
I've even been considering upgrading my G0602 to a larger PM lathe, maybe later this year.

The main reason I wanted the horizontal spindle, is some of the parts I am making are about 24" long and have narrow grooves in them that a slitting saw is perfect for Maybe the only way since some grooves can be about 1/32" thick. Anyways, I have two 6" vises on my table now and and put the part in side ways and cut the grooves this way. If needed I can still get the horizontal attachment, but at around $1k, I'm trying to do without for as long as possible.

The two vise set up works well for me, since I have other long parts that I work on and indicating them in was less of a pain than I though it would be. I ordered 24" long piece of flat ground steel from McMaster-Carr and use that as a parallel after the first vise is trammed.


Along the same part, I also have to put some counter-bored and tapped holes in at 45 degrees, which is still a pain. I thought the G0757 would have been handing with, since the table can rotate. It hole is about 13" up the the length of the part, so I can't support it above the table (maybe if I make a fixture and dropped the knee way down). So every now and then I get to practice re-tramming the head, but that's life. I've been thinking about buying a Harbor Freight mini-mill and setting it up to do this one operation and leaving it that way.


I've never bought a machine through Grizzly, only accessories (the G0602 is second hand). But I've read too many stories about their bad customer support to risk getting a 'rare' machine from them that will be hard to find support for else where.
 

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lcrepairs

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#11
I didn't realize the PM machine was in the same price range. Does a Vari speed limit power on the low RPMs ?? I don't see the full specs on the website. I'm guessing it's possibley 9x50 instead of 9x49 ?? I had already ordered the G0796 on backorder. I wonder if I could cancel and order the PM? Not sure what their policy is. I would rather have the Step pulley model since it's $400 less
 

grantj

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#12
I don't own a variable speed head, but I believe they have back gears like step pulley mill for more torque.
The vfd I installed on my pulley head mill claims it has torque compensation at lower frequencies. It's set up and I have never had an issue with torque, but I could put the mill in back gear if needed.

Unless you have 3phase power in or already own a rotary please converter, then you'll need a VFD anyways, so I'd go with a step pulley. I have a potentiometer above the power switch on my mill (white box) to control the speed.
 

mksj

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#13
A vari speed does not limit power or the mechanical speed ratio vs a pulley drive. A Vari drive just allows continuous adjustment of both pulleys, i.e. as you make the adjustment one pulley squeezes together while the other expands. It allows specific RPM control on the fly without stopping the machine, releasing the motor and having to change belts. It requires a heavier belt and a bit more complexity and to some degree other wear parts. The vari-speed tend to have a much higher top end RPM. They have been used for decades and are very well proven. Unless you are planning to go with a VFD, highly recommended to go with a Vari speed. Between the PM 9x50 and 9x49, be aware that the latter is made in Taiwan, the former is of Chinese manufacturer. If given the choice, I would go with the 949 at this spend level (but it is 1K more), but both will get the job done. Both of the Grizzly machines seem to be of Chinese manufacture, but look like nice machines. There are a number of options at this price level.

Should have added this, both pulley and Vari speed have back gears that set the low end speed range. On the Vari Speed head there are two windows which give the ~speed based on if you are in back gear or not. A pulley drive will have the same relative ratios, just reduced by a factor of something like 8 or 10 when in back gear. Some mills (like the 949TS pulley version) have a 2 speed motor, so you have a wider speed range (or speeds) which is more attractive if you go that route.
 
Last edited:

lcrepairs

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#14
Since these Machines are sold in both Single and Three Phase, I can't figure out for the life of me why people buy 3 phase then have to add a dumb VFD. As far as 3 Phase you are miles ahead with Rotory Phase converter anyway, but of course that wouldn't give you variable speed but these come with Variable speed heads anyway. HMMM, scratching head still.
 
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