Gunsmithing Grizzly 0709 spindle chatter

[lion]

I want to insulate the motor from the lathe. There is a 3 inch bracket between the motor and the lathe. Do I need to insulate between both sides of the bracket or just one side? If one side, which one? Thanks for any help. Wayne

 

[ugsly]

I want to insulate the motor from the lathe. There is a 3 inch bracket between the motor and the lathe. Do I need to insulate between both sides of the bracket or just one side? If one side, which one? Thanks for any help. Wayne

Are you getting vibration from your motor that is causing trouble in your finish on the part your cutting? I put anti-vibration pads between the motor and lathe and went to the v-belt and it helped some.

Kc

 

[rero360]

I would say, and this could be just the drunk ramblings of a machinist in training, the best bet would be to isolate the motor though the use of rubber bushings like on the current Harley motors, and then for even more isolation, use rubber bushings (or other vibration isolation material) at the other end of the drive as well, where there motor attaches to the spindle. If that makes sense, first time drunk in roughly a year is interesting.

 

[ridgeway]

Let's see your tooling and setup. Might not have anything to do with your motor.

 

[lion]

I am pretty sure it is in the motor mounting since the vibrating is present all the time. It could possibly be in the bearings, but highly unlikely. I have tried both carbide tooling and HHS and both chatter with carbide being worse than the HHS. I will do the isolation first and if that doesn't stop it I will be back for more information. Thanks, Wayne

 

[northern50]

If you have motor vibration that you can feel it is most likely at 1x rpm. Belt drive?? Replace the sheave, and make sure the key is cut to the PROPER length. There's lots of info on the web about how to size a key,
Google it. An electric motor should run with almost no felt vibration. Isolation pads are not going to solve the issue. Fix the root cause. Check belt alignment, and tension too. Indicate the motor shaft, make sure it's not bent.

 

[ridgeway]

Maybe take a video of it and post it?

 

[lion]

Pictures is the best I can do. When I push down on the red lever to start the spindle I can feel the vibration in the lever and in the slide. Isolating motor bracket from the didn't help. Don't know what to try next. Wayne

 

[northern50]

Take the belts off and fire up the motor. Tell us if it still shakes.

 

[Raven 6]

Take the belts off and fire up the motor. Tell us if it still shakes.

If it does the motor is out of balance and will need replacing.

 

[lion]

northern50 & Raven Rifles; Those last two posts were ones I really didn't want to see. This is just a hobby for me and I didn't want to go that deep to fix it. Unfortunately that is what is probably required. I will try that this coming week. Thanks for the replies. Wayne

 

[northern50]

If it does the motor is out of balance and will need replacing.

Not necessarily the motor being out of balance. It could be the sheave not being balanced, or it could be due to an improper length piece of key stock, or it could be an improper fit between the sheave and the motor shaft making an eccentric fit to cause imbalance.

Lots of things to check before condemning the motor to imbalance.



Does this machine sit for a long time? Does it have cheap belts that take a set over time? That would give a vibe frequency of the belt speed and not the motor rpm though..


This would be a lot easier if I could just take a vibration reading and tell you what's wrong with it lol.


Also make sure the motor mount base is flat and you are not inducing any stress to the motor causing a soft foot. That will give a 1X rotational speed vibration too.



Edit: Wayne, take a picture of the sheave showing the length of key stock on the shaft if you can get to it.

 

[JJones75]

Take belts off and run motor , then run it without the sheave , the sheave could be bad or out of blance.
If the motor runs smooth then it could be in the gearing or a bad bearing in the low end some place.
I also notice how much stock you have sticking out of the chuck , to much hanging out can cause tool chatter as well

 

[bward]

I would suggest working with less stock hanging out of the chuck and see if that doesn't fix your chatter.

 

[Raven 6]

I'm just speaking from my experience so don't take it as gospel. I had the same problem with my lathe which is exactly the same model you have. Mine was present from the very beginning of set up. I can the rep at Grizzly and after running several different test he determined that it was in the motor, they sent me a new one and after installing it solved the problem. That's all the experince I have to go on, I'm diffently not a electrical motor expert. I just know what it took to fix mine.

 

[wnroscoe]

Install rubber shims designed for motors between the motor's mounting bracket and motor feet. Loosen the belt slightly and don't over tighten it. Just snug hand tension is good enough. It looks like one of the cheap Chinese motor's that's used on those machines. I had a motor issue with an early Grizzly lathe I owned, it made noise from day one, if it's a single phase version it only compounds the issue. If it plugs into a 120 volt wall outlet (receptacle) it's single phase.

You can replace the motor and get a better USA made version and take care of most of the issue but, mounting hole alignment will be a PITA and a special bracket may be needed. I believe there's a motor supplier though that offers after market motors that will line up.

The last thing I'd do is suck some of that work piece back up in the chuck, you have way too much hanging out. That alone will cause chatter in the work piece by the tool/work piece spring back/push off. I'd only have enough hanging out to do my job.

Crappy cell phone pics but it gives you an idea of how much material to let hang out.

 

[Tac284]

I'm just speaking from my experience so don't take it as gospel. I had the same problem with my lathe which is exactly the same model you have. Mine was present from the very beginning of set up. I can the rep at Grizzly and after running several different test he determined that it was in the motor, they sent me a new one and after installing it solved the problem. That's all the experince I have to go on, I'm diffently not a electrical motor expert. I just know what it took to fix mine.

I have the same lathe, the above quote has been my experience except the second motor didn't fix the problem. It help very little. Also have a friend that has the same lathe with the same problem, his second motor was better then the one I received and reduced vibration but the it's still evident. I think my next step is to go with a us motor.

You should definitely pull the work back into the chuck if you can, if not use your tailstock to support. Good luck, I definitely feel your pain!

 

[lion]

I usually don't work with that much overhang on the chuck. I let that much stick out to see if the chatter lines would show. They didn't but I could still feel the vibrations in the bed of the lathe. The motor sheave has uneven wear marks on the inside where the belt runs. The lathe uses two 1/2 " v belts. I will check runout of the motor shaft and sheave next week. Except for this problem I really like the lathe.

This is what a barrel looks like with chatter marks. Wayne

 

[ridgeway]

By judging by the turned barrel section...looks like a tooling issue. Are you centering your tool bit making sure its not too high to too low? Enough clearance ground on the bit? How about changing your feed a little on your gearbox...reverse your drive and try a cut from left to right. Maybe there is a possible gearbox issue. Try feeding the carriage with the lead screw and halfnut without taking a cut to see if the vibe is still there.

 

[lion]

ridgeway; I'm not ignoring your comment about tool chatter but I ruled that out early on because with an empty chuck and no tooling in the tool holder it starts to vibrate as soon as I start the spindle turning. I can feel the vibration in both the cross slide and in the bed ways. The bed ways a little less so than the cross slide. I didn't notice the vibration early on because I used the machine very little. It took me a few months to get the DROs installed and a while longer before I did any work where the vibration really showed up. By then I had the lathe for over a year and good luck with any real help from Grizzly. I still have an oil leak they did nothing about so I quit calling them. I get better information from members who actually use the lathes. I appreciate all the replies trying to help. Wayne

 

[Tac284]

Lion, your story hits pretty close to home for me. When I received my G0709 I didn't use it as much as I anticipated. I also spent a long time building all the brackets for the Grizzly DRO because everything that comes with the kit doesn't work with the lathe. Time flew by so fast and before I knew it a year had almost gone by when I notice the motor was making so much vibration. I was able to get one under warranty but like I said in the earlier post it didn't fix it. I can tell you one thing though, the back splash is definitely a transmitter for the vibration. I ended up building better brackets to hold it which helped with some of the sound vibration but it's still evident in the ways and cross slide.

I believe I had found a us motor that would fit the bolt pattern and have similar overall length to the grizzly motor. I will have to find my notes when I get home, if your interested in the same motor let me know and I will send you the details.

 

[lion]

Tac284; I had to smile when I read your comment about the backsplash because I had to remove mine to get to the motor bracket. My lathe too still vibrates just as bad without it installed. I would be interested in your motor information. I was going to start my search with Grainger and expand from there. I will be doing a lot of googleing next week. Wayne

 

[JJones75]

Look at the ID plaque on your motor , where it tells the HP and RPM rating , it SHOULD have a frame size. Typically starts with a "T" that will be the bolt hole pattern and typically a standard shaft size and ground to shaft center height. Use that frame size as across rereference to find a quality motor.
A lot of times what you will find in electrical motors is that if they sit in storage for a lenght of time the bearings will get "spots" on them that will cause excessive vibrations and premature failure.
Another issue belt drive equipment suffers is people run the belts WAY to tight. The belt is a sacrificial part , cheap and easy to replace compared to motors or bearing , wearing out a dozen set's of belts per sheave is common after 10-12 sets of belts (depending on application) the sheaves should be replaced as well (unless its a cogged sheave).
If you want ill mail you a belt tension gauge to borrow and get it adjusted properly.

 

[338RUM runner]

I want to insulate the motor from the lathe. There is a 3 inch bracket between the motor and the lathe. Do I need to insulate between both sides of the bracket or just one side? If one side, which one? Thanks for any help. Wayne

Wayne, What is your lathe sitting on, do you have any kind of mount under it, bolted to floor ? I have the same 0709 lathe and mine runs smooth, I used the rubber pads that Grizzly sales. PS: mine does have some vibration to it , I can see the light shake.

 

[lion]

The bad news this morning. I removed the belts and the motor sheave and can still feel vibration in the cross slide and bed ways. This is with isolation pads between the lathe and motor bracket. Checking now on motors available. Near as I can see now there is no frame size listed on the motor spec plate. Wayne

 

[colchester]

Lion might be worth it to remove the motor and run it to an electric motor repair shop. Might need bearings or a capacitor a switch ect. Sometimes they can be repaired for way less than new. Its also completely possibly, judging by some of the replies in this thread, that the motors are crap and you will need to replace it. I would have a motror guy check it out and see if it can be repaired on the cheap

 

[vxsystemsltd]

Put a smooth shaft in the chuck, centre it and observe the needle on a good dial indicator. If the needle constantly jumps around when turned by hand you have a bearing problem. I went through this with a Grizzly after about fifteen barrel jobs. The bearings were shot and the only bearings available in this size were basicly truck bearings, nothing of higher quality existed. Anyway I replaced the bearings and sold the lathe in better shape than new with the new Timken bearings. I did try linked belts etc and nothing helped which led me to the bearings.

 

[lion]

I put rubber pads between the mounting bracket and the lathe and between the bracket and the motor. Sort of double isolating it. That helped a lot. Didn't get rid of the vibration entirely but good enough for my purposes. Thanks for all the suggestions. Wayne

 

[LRI]

If I may attempt to contribute:

A few years ago an ammunition manufacturer indigenous to my little part of the world purchased one of the Grizzly machines. A short time elapsed and I was approached about surface finish issues they were experiencing. On the advise of another well known smith they'd purchased vibration isolating feet and setup the machine to run as quiet as they could manage. Still, the surface finish problem existed.

Why? Why are you trying to isolate the vibration from the floor? Does it make your feet numb like when you ride a 2 stroke dirt bike all day? You want rock solid machine placement. If there are machines nearby that are subject to the vibration being transmitted then its a good application. If your a one man band running one machine at a time then anchor that biche or have your slab done on monolithic blocks so they are independent of one another.

Speculation ran as to the cause. Poor bearing quality, carriage fit, yada, yada. The full gamut of alarming topics that seem to target the imported machines these days. (a different subject where I could rant all day)

The cause was simple. The wrong tools for the job. They'd gone the affordable route and bought brazed carbide tooling and even attempted to take a stab at grinding some of their own stuff.

Here's the deal bud. Your machining. Doesn't matter if its a hobby, a trade, or a business. Your cutting metal. Take advantage of what the science has to offer. Gun parts are not cheap. Scrap a barrel by blowing up a reamer or by nuking a tennon when threading it what happens?

You thaw out your Visa card. That's what happens. So ask yourself. If its worth ruining a part that costs to the tune of almost $400 bucks wouldn't it be much better to buy a tool that will mitigate the risk? If you can afford to do it twice, you can certainly afford to do it once right?

Understand, I'm not talking down to you. If I come across that way I apologize as its not my intent at all. All too often we are suckered into this delusion (myself included) that because I'm a "hobby guy" I'm excluded from having to cough up the shekels that an industry guy needs to spend.

The laws of physics are universal. They don't change based on commitment.


Your working with heat treated materials. Stainless steel isn't known for being exceptionally forgiving. Barrel steel fortunately is one of the more forgiving varieties. That said its still one of the materials (416 SS) that responds much better to insert tooling designed for it.

In your case I'd opt for an insert. ditch the brazed carbide stuff. The grade is wrong and the lack of coating means its wrong too.

I'd encourage you to consider a VBMT style insert with a 331 IC. The ones I use are from Sumitomo. Not cheap, but there are more affordable alternatives. BASS tool down in TX sells some for as little as $9/each. Buy a pack of ten and it'll likely last you a couple years. Get the appropriate coating for working with SS. The vendor will help you with this.

The VBMT style insert will allow you to both rough and finish with one too. Depth of cut on a machine like yours probably shouldn't exceed .05" and .005/rev.

Next ensure your setting your tools up properly. The easiest way to set a turning/facing combination insert is to just wizz a piece of stock across the face and adjust your post height until it doesn't leave a tit at the center.

Then get a tool holder. Don't cheap out and buy an import from the bottom feeder machine tool sites. Get a good one from an established company. Buy the largest holder that will fit in your post. Min 1/2" but 5/8 or 3/4 is even better. Mass means rigidity. MASS EVERYWHERE helps.

Now, get yourself acclimated with speed and feed charts. Here's an example:

http://www.sumicarbide.com/pdf/turn/TB_RecRun_CCC.pdf

Here's an online calculator that'll give you a quick solution to what rpm to run at what feedrate:

Turning Speed and Feed Calculator


My reason for posting all this is to try and help you out. I'll qualify what I'm saying with this:

From 1999 to 2003 I used a Jet lathe that was over 15 years old to fit barrels for olympic resident athletes. It was a horribly worn out machine. Sags in the bed, low power, etc.

With careful tooling selections the machine was still capable of fitting barrels that later went on to win Olympic Gold Medals.

Tooling matters!

Good luck and Happy new year.

C.

 

[JJones75]

I've never seen the reasoning behind mounting a machines to rubber pads rather than a rigid base.
I work for an aerospace contractor and when we install tool from 12" lathes to massive multi million dollar friction stir welder/mills they all get their own independent reinforced concrete base. The vendor's idea behind this is that machine anchored solid to the base will only make the machine more rigid.

Aside from that Chad is spot on with proper tooling , investing in the right stuff will help save A LOT of money down the road. I know that insert vendors are always comming to see our machines and what we want to do so they can help figure out what tool and coating is the best for our work and coolant used.

All that said if the machine is having vibration issues running to warm up then it sounds like a balance , alignment or bearing issue.

 

[LRI]

I've never seen the reasoning behind mounting a machines to rubber pads rather than a rigid base.
I work for an aerospace contractor and when we install tool from 12" lathes to massive multi million dollar friction stir welder/mills they all get their own independent reinforced concrete base. The vendor's idea behind this is that machine anchored solid to the base will only make the machine more rigid.

Aside from that Chad is spot on with proper tooling , investing in the right stuff will help save A LOT of money down the road. I know that insert vendors are always comming to see our machines and what we want to do so they can help figure out what tool and coating is the best for our work and coolant used.

All that said if the machine is having vibration issues running to warm up then it sounds like a balance , alignment or bearing issue.

While working for Dakota we considered a number of machines. One was Okuma. When the rep came first thing they looked at was the floor. We were told we'd have to have isolated pads for the machines otherwise it voided the warranty. Dakota's answer was to buy Kitamura and the city put up a purpose built building to suit the machines. The floor is more like a lid for NORAD than a floor. It's a ridiculous piece of concrete.

Glad to know I'm not completely crazy for spewing this stuff to the masses...

Why? Why are you trying to isolate the vibration from the floor? Does it make your feet numb like when you ride a 2 stroke dirt bike all day? You want rock solid machine placement. If there are machines nearby that are subject to the vibration being transmitted then its a reasonable application. I personally have yet to see it, but who knows? If your a one man band running one machine at a time then anchor that biche rigid or have your slab done on monolithic blocks so they are independent of one another.

I think we agreed on this too. Went back and edited some points as I should have done in my first post.

 

[lion]

Chad & JJones; I really do appreciate you guys trying to help. If I were 23 instead of 73 I would be trying your suggestions. Age & funds keep me from changing too much. Probably will order a 5/8 tool holder and a few inserts. I know my tool height is right because I set the height the way you suggested. If I get real disgusted with the vibration I may mount the motor on the floor behind the lathe and use longer belts. The trouble is my shop is just a garage floor about 4" thick and not much room to operate. I think I was just looking for a cheap easy way and we know there is no such thing. Wayne

 

[JJones75]

Wayne , the idea of mounting the motor off of the lathe is a good one , you could get some vibrations through the belts but it wuld be less. If your belts are in bad shape or your sheaves are bad then the lathe will still vibrate but it worth a try.

 

[CS223]

I have the same lathe and similar surface finish issues. I used the proper steel leveling pads rated for 6000# each stting on a concrete floor. Item No: TL-3 [Steel Stud Type Leveling Pad] and I leveled the lathe using a 10" precision level good to .0005" in 10" I notice the OP doesn't have the lathe bolted down and probably not leveled.

The problem persists at all spindle speeds with various harmonics. Worse on steel and stainless steel. Not detectable on Delrin. I checked & readjusted the spindle bearings and checked the spindle runout which is imperceptible on a .0001" B&S DTI which I found shocking for an import lathe. I disassembled the cross-slide & compound & cleaned everything & readjusted the gibs before ever running it for the first time. I added a lever lock to the compound. I also went over all the fasteners, and made other adjustments where necessary, quite a few fasteners were loose. I run all insert tooling with the proper matched inserts & F/S. Hard & heavy cuts to squash all the play out of the carriage & cross slide.

The motor pulley has one inadequate setscrew that doesn't tighten on the key. I removed the pulley and added a 5/16 setscrew over the keyway. I also took both the motor & spindle pulley and removed all the paint from the belt grooves. It's a PITA to adjust the motor alignment, but I found that using only moderate belt tension as opposed to fiddle string tight reduced the gearbox noise. and/or the transmitted motor noise. Tried just one belt in case they were mismatched but that made no difference. They are good quality Gates belts btw.

This is not my only lathe or machine equipment for that matter, I also run a restored Lodge & Shipley 16" Toolroom lathe & a Hurco VM-10 VMC, and I have several other mills & lathes. The Grizzly was purchased for the through-the-headstock capability & second light operations.

My personal opinion at this point is that the surface finish issue is related to the lack of rigidity in the lathe stand itself. The so called cast iron stand is the thinnest cast iron I've ever seen and it lacks any significant gusseting. I think the bottom flange of the stand which is supported by the leveling pads is flexing allowing the lathe to bounce & twist. you can feel the vibration in the tailstock when the lathe is running. I'm thinking my plan at this point may be to weld up a 2"x2"x1/4" wall box tubing sub-frame that the lathe stand cabinets will bolt to using the leveling pad holes, then the leveling pads will attach to the sub-frame.

IMHO, using the leveling pads is probably a bad idea on the stand itself and it probably wasn't designed in that way. I'm thinking that it would be better if the stand was on the floor and the holes used to secure it to the floor though that might make it more of a challenge to level. If you look at the underside of the stand cabinets you'll notice that the corners protrude some compared to the periphery of the cabinet bottom and I'm thinking all four corners of each cabinet need to be in contact with the floor or other support structure for proper support. There is no tie between the two stands, leaving the lathe bed open to bowing/flexing. I may experiment by tying the bottom of the bases together mechanically to see what effect it has before going through the trouble of building a sub-frame.

 

[CS223]

Another tip for G0709 owners, the metric rollpin that secures the tailstock quick release lever to the cam assy will fail on you, it's only a matter of time. You can remove the cam assy and tap the cross hole for the rollpin to 1/4"-20, no need to drill it. Use two short SHCS on each side to secure the lever to the cam assy.

 

[338RUM runner]

I think I'm going to fill my stands with Quikrete non shrink grout and tie the stands together with tubing. I'm also making a new key for the motor that will balance the keyway better.

 

[JJones75]

I think I'm going to fill my stands with Quikrete non shrink grout and tie the stands together with tubing. I'm also making a new key for the motor that will balance the keyway better.

Don't over look the sheaves , more often than not they are casted and nowhere close to being balanced or true. They are not hard to make from round stock.

 

[CS223]

Don't over look the sheaves , more often than not they are casted and nowhere close to being balanced or true. They are not hard to make from round stock.

If you are going make new sheaves, machine them for a serpentine belt, less vibration than v-belt.