What's new
What's new

Scotchman cold saw making horrendous noise

daer21

Plastic
Joined
Apr 18, 2012
Location
North Carolina, United States
All,
Hello, I'm new to the forum and this is my first post, so if I've missed the answer to my question in the 'search' feature please forgive me. I tried. I've got a Scotchman 315 HFA cold saw. We use it to cut 14 .25" shafts at a time in a diamond pattern held in vice jaws. (first starts cutting one, then two, then three then five then works back down to one) We are having problems with it producing excessive noise. It makes a terrible Rrrrrr Rrrrr Rrrrr noise the entire time it cuts. We put a sound meter to it and its hitting 95-105 db. It also produces severe vibration at times. Sometimes that severe vibration comes and goes, so it will go rrrr rrrr rrr Rrrrr RRRRRR Rrrr rrrr Rrrr RRRRR Rrrr rrrr. We currently use an alternating grind (via the Scotchmen blade ordering guide) and a 220 tooth blade (5.5ish pitch) It is quietest at around 20 RPM. To try to resolve this issue I sent a couple blades back to scotchman for sharpening. Their new blade helps somewhat, but I still get the same Rrrrrr Rrrrr Rrrrr noise. I also tried going to a 180 tooth (4.5 pitch) blade and a 150 tooth blade (4 pitch). The 180 tooth blade was about as quiet at the 220 tooth blade, though I had to run it slower, around 16 rpm. The 150 tooth blade cut quiet as a mouse during break in, but when we tried to speed it up to production speed the machine shook violently was just as loud as the saw has ever been. That was regardless of speed. In order to keep production up we don't want to cut down on the downstroke speed, I need to only change the speed of the blade.
Does anyone have ANY ideas? I'm at my wits end here. I'm not a saw person, so I'm a bit out of my element here. Any help would be appreciated.

Edit: The saw already has a VFD fitted. The first thing I did when I started working on it was slow it down from 47 rpm to 20. 47 RPM was INCREDIBLY loud.
 
Maybe you could better explain how you are cutting. You say a diamond cut on 14 .25" (is that 14 - 1/4" rods ?)
I don't understand "a diamond cut".
 
Sounds like he is stacking a quantity of 14 .25" diameter shafts and cutting them all at the same time. The 'stack' is in a diamond pattern.

I get horrible sounds out of a saw if I forget to tighten the vise and/or the round stock starts spinning when the blade hits it. (more of a grraw grraw graww :) :)

Check to see if one of them isn't spinning (weld all 14 together as a test to eliminate the possibility).
 
Have you used alot of coldsaws? I have the same model of scotchman that you have, I use it everyday. I cut 1-2 inch solid steel bar with it. I use a 10 inch blade with a 120 tooth and it makes so much racket. It is worse with blades with more teeth. I have found that more pressure on the cut stops the noise, that is counter to what most people do, they ease up on the cut. I have used alot of different brands of coldsaws and all of them make some noise the scotchmans make the most. Haberele and doringer seem to make the least.
 
... We put a sound meter to it and its hitting 95-105 db. It also produces severe vibration at times. ... 47 RPM was INCREDIBLY loud.

You never mentioned whether it produces a similar noise when cutting a single piece.

I thought I had a similar problem and opened the gear box, only to find it was like new. I was then told the noise is inherent to the Cold Saw which is much noisier than the band saw. Unfortunately we cannot compare noises without attaching mp3 files.
 
Answering in a semblance of order, Jamscal has the right idea as far as what I meant by 'diamond cut.' The saw was purchased in an aluminium cutting configuration (gearbox let is spin faster) and was converted to steel by changing said gearbox. The saw is never used to cut anything OTHER than these steel shafts as its used for production, not jobbing. It runs 3 shifts a day, 5 days a week, all on the same material. We do change the blades regularly. The operators suspect the form jaws are worn, and I'm wondering if they are right. I don't think any of the parts spin, I've looked and never seen it, but I'll double check to be sure. We have several other cold saw used with the same intensity, one scotchman, another some other brand that escapes me at the moment, and both are significantly quieter. Neither of them makes any significant noise over the baseline drone of the plant, this scotchman that is giving me trouble is the single loudest thing in the entire company. Does anybody have any idea why it would behave so oddly with the 150 tooth blade? It would make a trim cut, and then stop and pop back up when it went to make a test cut.
 
Lose parts are vibrating as they cut. Weather its production or not just sling something else in there and take one cut, still noisy it the saw, otherwise its the part making a din!
 
I have a Scotchman style saw and an Eisele and they are both loud. The scotchman style saw sits on a heavy welding table and I put a piece of heavy rubber mat under it and that helped some, and using cutting oil wiped onto the blade seems to work better than water based coolant, but not a great solution for production runs. Have you thought about an auto feed saw with a sound deadening hood to make the shop quieter?
 
The Scotchman 315HFA IS an auto feed saw. And it does have a hood, at least stock.

I think first you need to figure out if the noise is coming from the saw or the workpiece.

If its the saw, and it happens with different blades, then something is probably loose or worn inside. Could be as simple as the retaining nut that holds the blade on. Or in the gear train, I suppose, but those are usually pretty bulletproof.

If its in the work, it could be vise jaws, as you suspect, or vise tightening, again, something worn or loose.

They sell automotive grade stethoscopes for just this kind of diagnosis.
 
I didn't get a chance to run a piece of bar through it yesterday, but I did check on the pieces to see if they were spinning. They are not, and seem to be held pretty darn well. There is minimal slop in the clamps. Would 1-2 thousandths make this much racket? I will say that the plant manager slowed the cut time down to 20-25 seconds and the saw became very much quieter. It's still loud, but not floor shakingly so. It does have a noise hood. The incredible sound level was WITH the hood believe it or not. I'm going to try to cut a solid bar today to get an idea. Our custom sharpened blades are also coming back from the sharpener, so I can see if that will help. I'll look it over to see if I can find a lose joint somewhere. Is there a particular way to tell if the screw that holds on the blade is worn? It looks to be just a conventional 3/8" hex bolt and it tightens down nicely.
 
We can help you work this out.
The number of parts going one,two,three,five,three,two,one adds up to 17 pcs?
I need exact details so i can calculate proper tooth pitch and feed rate for your application.
I also need to know the total rpm range or the rpm at 60Hz on your freq drive so I can determine where your peak torque is available.
Distance of gap between your clamping jaws can also play a role in this but most likely the main factors will be as follows.
RPM, Feed Rate, Tooth Count, Coolant / delivery and last and equally important is the grind geometry applied to the blade.
I am confident with the information being provided I can offer a quick resolution to your issues.
 
I saw a presision cold saw once with dampening pads on both sides of the saw
A bit like a disc brake but with just a little pressure
It cut 40mm bars like they were ground and also very quit

Peter from Holland
 
1-2 thou will vibrate like buggery! There either all clamped 100% or some are allowed to vibrate. Being lose enough to spin would destroy your blade.
 
Sorry for the delay in reply.
Triple chip:
Pattern: 2-3-4-3-2, .25" shafts
Speed at 60 hz: 47RPM
Max blade size: 315mm
We use flood coolant powered on a separate circuit from the motor.
Cut time: 20-25 seconds
We are moving from 220 tooth alternating grind to 220 triple chip grind with a modified (per manufacturer recommendation) profile. This helped a great deal but its still louder than it should be.
Still haven't had a chance to run a square bar through, things got busy on me all of a sudden.
 
Thanks, the information helps.
Your material area being cut is 1”x1.114” so your tooth count on your blade is based upon the 1” cross section. There for the recommended tooth count should be about 120T.
The rpm your machine is running is a little faster than we would prefer for cutting carbon steel using a basic M-2 HSS blade so I would slow the rpm down to 40 rpm from 47 rpm. This should put you at about 50Hz where most freq drives still deliver an acceptable level torque. This reduction in rpm will put your rim speed of the blade at about 130 SFPM which is still a little higher than I would prefer but we can offer a TiCN coated blade which will help with the wear resistance.
I would start out with a feed rate of .0015 IPT, at 40 RPM you will be at about 7.2 IPM or a traverse speed of .120 inches per second. At this rate your cutting time should be about 10-12 seconds depending upon the length of your total stroke being used.
Coolant preferred would be a micro mist type with a Vegetable based lube but with your current system I would target about a 7:1 ratio on a water soluble type fluid if that is what you are using.

I will send you a private message outlining your blade options, but this should help with your noise issues and increase your blade cutting performances while decreasing your current cycle time.
 








 
Back
Top