Cold saw clamping arrangement

[leeko]

Hi all,

I'm cleaning up an old Brobo Super 300 (Haberle H300) cold saw, which had been badly neglected by the previous owner.

I've refilled the gearbox, rewired the motor and made a quick test cut in 1" x 2" mild steel to make sure it works before plowing too much time into it. It made it through, but it was really noisy and required more feed pressure than I'd like. The cut was ugly and there was a fair bit of galling/smearing evident.

I've identified a few reasons for the problem, and am sure all were contributing at least some:

- dull blade (ready to be sharpened when the shop reopens next week). It's a 300mm 180 tooth "general purpose" blade running at 54rpm. I'm hoping this is the majority of the problem.

- loose motor pivot bolt (now tightened)

- backlash in the worm gear, which translates to ~1/8" backlash at the teeth of the blade. Not sure there's anything to be done about that, I don't see any obvious adjustments.

- rusted and pitted blade mounting flange (now stoned flat)

The one thing I'm not sure about is the vise/clamping arrangement on this saw. It clamps only on the left side of the material. On the right side of the cut, there's a rear jaw but no moving jaw. When I looked closely, I could see that the material doesn't actually touch either the back or the base to the right of the blade (the supports are too far back and too low) and figured that was likely why the cut was so noisy.

But... on the few pictures I've been able to find of this saw, it looks like it's usually set up without ANY support on the right side.. so, should I ignore that and Just hope the blade fixes the issue for me?

I'm running astrocut lube, diluted 10:1.

Thanks in advance for any help!

Lee

P.s. I know it's filthy. I'm working on it.... Believe it or not, this is after an hour of scraping crap...

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[Rocketdc]

My guess is you'll see significantly better cut quality when you try again after tightening everything up and using a sharp blade. My cold saw has a vice that clamps on both sides for straight cuts, but I can only use it on one side for angles. I've never had an issue with cut quality when clamping one side using a sharp blade.

 

[garyhlucas]

The blade in the picture is too fine for a 1" x 2" piece of steel. When a cold saw cuts the chip rolls up in the gullet between the teeth. If there is not enough room the chip jams and welds to the material. Often it will break the blade if you force it. This is a bigger problem than a blade that is too coarse in most cases unless you are cutting very thin stuff. To cut a wide range of materials on a cold saw typically requires a set of nine blades. Three pitches minimum, and for each, one on the saw, one waiting, one out being sharpened. If you only cut a small range of thicknesses you can get away with 3 blades.

 

[Strostkovy]

In my experience with cold saws the chatter is directly related to the feed pressure and little else. Get a sharp blade and you'll be fine. My "project" coldsaw (I actually finished it, believe it or not) has a vise that clamps both sides (It actually moves the front and back of the vise to center it) and while nice for most stuff I dislike it for trimming off less than an inch of stock. No big deal really, just put a piece of dummy metal in the other side of the vise to keep the forces balanced. It still chatters significantly no matter how well the stock is clamped if the blade is dull and it has to be forced. I suspect the blade itself does the chattering, being so thin and under so much stress.

Ditto on the blade pitch, stick with something coarser. I hear people repeat that three teeth must be in the cut at all times but I cut with just one tooth for sure in the cut on lots of stuff (and less than that on thin wall stock) with no problem.

I reevaluated how much I believed in that statement once I used a dry cut carbide saw that has a 3/8-1/2" tooth pitch on thin materials and never had any issues.

 

[leeko]

Thanks everyone for the advice. I'll look for a coarser blade, and get this one resharpened for thinner stuff. Would a 120 tooth be a good general purpose blade for stuff in the 1-2" solid range?

w/r to keeping 9 blades handy: um, no. ~$1000 on saw blades isn't going to happen in my hobby shop. Waiting a few days for a blade to get sharpened is fine for me - horses for courses.

Thanks again, and merry Christmas

Lee

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[Rocketdc]

I had a 140 (315mm) recommended by my supplier for 1/4-3/8" and it works fine, but I have a feeling coarser would have been better because the stock I was cutting was 4" wide.

120 will work, however you might want to go coarser for 1-2" solids. Since you're not cutting a lot of material I wouldn't worry about "optimum" tooth count, just use a blade that's recommended within the range of material you're using, make sure it's sharp, coolant is flowing and test your down feed pressure to see what gives the best results.

 

[leeko]

Thanks again for the advice - I've emailed Quinn Saw to get Triplechip's recommendation on a new blade and sharpening the old ones.

Does anyone have any tips on freeing up the head swivel? This thing was in a terrible state when I got it - I've scraped off about an inch of rusted solid chips and dried coolant from every surface, and sprayed a liberal coat of of PB blaster on everything that looks like it needs it.

Everything moves pretty freely, except the main swivel to turn the blade for mitering. It feels rusted solid. I've squirted some grease into the zerk, and it squeezes out between the swivelling parts, at least on the side closest to the zerk. The lock handle on the same side also moves but is very stiff - it requires a few light hammer blows to get through the full travel.

I don't see any obvious way to disassemble the thing from the top - do I need to flip it? Or are there any other tricks to getting this thing moving again?

Thanks in advance

Lee

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[metalmagpie]

On the head swivel, penetrating oil is your friend. Work some in all around the edges, keep forcing it one way then the other and it will let go. If you use soluble coolant I don't know of any way to avoid this. That's why I ran soluble oil in my last cold saw.

On the vise jaws, make a single back jaw bolted to both sides. Then cut it with the cold saw. The part will be clamped against the left side and if you want it clamped on the right, use some Vise-Grips.

You have to watch wear in the gearboxes on old Italian cold saws. I'd pull the covers from the gearbox and have a good long look in there. Once the teeth start going on the bronze worm gear it's hard to stop the deterioration. You want to be especially sure all the fasteners in the drive train are tight. On my old Thomas saw I had to make a wrench to hold the back nut of a pair of lock nuts. Then I could tighten the front nut with a socket wrench.

You have to be careful to use gear oil that won't hurt your bronze parts. The key words are "Suitable for Applications Containing Yellow Metals". I bought Mobil SHC-634 from zoro when I had free shipping for some reason.

The blade vendor I used to use was HSS Cold Saw Blades - Cold Saw Blade Store.

metalmagpie

 

[leeko]

Thanks MM,

I'll persevere with the penetrating oil then

I looked into the gearbox last week, and it looks like there is some wear on the worm mechanism that translates into about 1/8” back and forth at the teeth on the blade. I didn't notice anything loose though. I also didn't see any obvious fasteners I could tighten from the top access cover. I'll try to take another look and take some pictures/video.

I used this when I changed out the oil in the gearbox - the blurb on the website says it should be safe for yellow components and seals:

https://www.amazon.com/dp/B004LEZPGK/ref=cm_sw_r_cp_apa_fabc_7Ip6Fb45BZ23B?_encoding=UTF8&psc=1

Thanks again

Lee



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[Strostkovy]

It took me an evening to disassemble, wire wheel, grease, and reassemble my rusted solid cold saw. Luckily it had no bearing or gear issues, just rusted table. I couldn't even turn the vise without a prybar when I started.

 

[triplechip]

Hi Leeko,
Give us a call at the shop and we can take good care of you on your saw blades. I can either retooth your present blade or get you a new coarser blade shipped out right away. If you buy a new blade I will resharpen the blade you have at NO CHARGE.
Bill
Quinn Saw | Circular Saw Blade Manufacturing, Sharpening, and Repair : Quinn Saw

 

[leeko]

Awesome, thanks Bill!

Talk to you hopefully tomorrow

Lee

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[440rr71]

WHen in doubt, I go to california cold saw. They have a calculator for number of teeth per thickness. I bought all my blades on ebay for 40-75 dollars per blade. I think I have about 6, from 90 to 240 teeth. I find my 160x350 is mounted most of the time.

 

[Strostkovy]

I just handed my old blade to our welding supplier, he took a picture of it, then brought a new blade the next week for $88. This was only a 250mm saw, but the price seemed nice and it sure was easy. Just told him what I was cutting and he dealt with getting the right tooth pitch.

 

[memphisjed]

You might want to pull the saw off the table to clean the pivot surfaces. There are some (4?) bolts under the saw in the sump that come out and the locking handle and wedge washers will fall into a corner of your sump. before you do this have something supporting the saw head so it doesn't fall (it shouldnt want to, but safety of an unsecured heavy object over your head is considerable). Once the head is off a quick wire brush, and maybe some grease grooves added (credit to recent cold saw post here) with zirks. The backlash is not really an issue, the blade is only working in one direction.

 

[Strostkovy]

You might want to pull the saw off the table to clean the pivot surfaces. There are some (4?) bolts under the saw in the sump that come out and the locking handle and wedge washers will fall into a corner of your sump. before you do this have something supporting the saw head so it doesn't fall (it shouldnt want to, but safety of an unsecured heavy object over your head is considerable). Once the head is off a quick wire brush, and maybe some grease grooves added (credit to recent cold saw post here) with zirks. The backlash is not really an issue, the blade is only working in one direction.

That's brilliant. I struggled with coworkers rusting up the cold saw because they kept topping it off with water and no coolant. I just blamed the shallow pan that the coolant drained into. Still going to make a better tray for it to sit in.

 

[thermite]

w/r to keeping 9 blades handy: um, no. ~$1000 on saw blades isn't going to happen in my hobby shop. Waiting a few days for a blade to get sharpened is fine for me - horses for courses.

Glad this came up just now! A PHS has near-as-dammit the same "gullet holding capacity" issue as to easy work or problem-creator and I'm re-mounting the Kasto for more frequent use.

But.. the hobby-shop hit for the investment in blades?

A mere $ 300 gathered me nearly sixty 18" PHS blades in 3 to 5 each of a wide variety of types, shapes, and pitches, all brand-new, major-maker goods.

Mind.. I'll probably be using the wrong ONE like as not... but still.. fast and easy to swap!

"Seems to me"... a cold saw is far the better fit when used for steady production, same s**t, different day, the "obsolete" PHS more flexible at "what do we have NOW?" & lower spend "hobby" use.

Bandsaws? ... 'nuther animal. On the list.. just not a priority, here.

You might want to peddle that Cold Saw?

 

[leeko]

You might want to peddle that Cold Saw?

Maybe

But not yet

I have an old power hacksaw in the corner, and it works just fine. It's slow, but as you suggested I don't mind cutting some gnarly stuff on it and burning up a cheap blade.

But I've always had a hankering for a cold saw.

And another mill. And another lathe. And a surface grinder. And a tool grinder. and a CNC lathe. And a bandsaw. And so on...

Lee

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[thermite]

Maybe

But not yet

I have an old power hacksaw in the corner, and it works just fine. It's slow, but as you suggested I don't mind cutting some gnarly stuff on it and burning up a cheap blade.

But I've always had a hankering for a cold saw.

And another mill. And another lathe. And a surface grinder. And a tool grinder. and a CNC lathe. And a bandsaw. And so on...

Lee

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Well..... "you are in the right place, here!" for tool-whores!



PS: DAMNED cheap blade? REALLY blade-eating "gnarly" goes on the abrasive chop-saw.

Good PHS blades have astonishingly long lives! DoAll, Kasto, and not-only still ship them brand-new and even integrated into largish CNC-controlled high-volume cutting lines.

Mebbe all you need is a better choice of coolant and/or more powerful pump?
Main job is to keep the gullets cleared as it cycles. Done well, heat itself is no longer a major issue.

Then again, much the same with a cold saw. COOLANT!

Yes. It is f**king MESSY! But worth it. Same as sex. Or so I seem to recall?

 

[M. Moore]

That blade is extremely dull. The cut should be smooth and near perfect like a slitting saw on the mill. I have two cold saws, an 11" and a 16" which is actually a 20" with a small blade installed. The 20" blades are way too expensive.

I would leave the vice and fence as is, it is better not to back up the offcut given that sometimes it can pinch the blade depending on the material. Always clean away any small offcuts so they don't end up in line with the blade travel. I keep a wooden stick handy to clear the area but my machines are semi-auto's. I had a small offcut of 3/4" x 4" flat bar that I cut on edge, a process I do very often, fall just behind the blade and get trapped. Then a loud bang as the blade broke, $400 later I had a new blade....

I have two Eisele machines and they have very good blade charts attached to the machine. They use tooth pitch rather than number of teeth so the blade diameter is not needed. Tooth pitch works with any blade diameter. I mainly use a 10mm pitch blade (3/8") for all my solid cutting up to 1" thick stock. For any angle or tubing 1/8" or thicker up to 1/4" I use a 6mm pitch and for ERW or 1/16" thick material I use a 4mm pitch.
I don't really understand why tooth pitch is not the industry standard as it is so simple. As you sharpen a blade the tooth pitch is reduced and sometimes they are retoothed to restore the original pitch. However they may be too small to cut much at that point.
I very occasionally will cut stock with an incorrect tooth pitch blade and it does work but it is usually for just one or two cuts, any more and I change the blade. Make sure that you take the lash out of the drive pins when you do install a new blade. Snug it a bit then slip the blade so the pins are tight against the direction of the cut.

You will really like the cuts if you ever have to do mitre cutting, the fit is so good I can tig weld with no filler.

Good luck with your machine!

Michael