[timmydabull]

i just recently purchased a used hyd mech 20 inch saw,i have refurbished everything like new except replaced the hydraulic downfeed system,the problem is i have been thru 5 blades of various types and teeth count and i cant get this saw to give me good results. and hyd mech has let me down big time wasted 2 weeks of my time and dont seem to have any level of quality support or service for this saw.

as of now it takes 35-60 minutes to saw thru a 7 inch round solid 6061 bar and if i dont stand over the saw and constantly adjust the flow control valve the saw will stop decending or decend too fast and break teeth off the blade.

i have never used a saw like this so i do not know what the normal cutting time or feed speed and blade configuration for optimal cutting.

one part of me says to replace the hydraulic cylinder but the other part of me is frustrated and ready to spend money i dont have on a new saw.

this saw has put me in a bind because i cant get material into the machine because i cant cut it,and there seems to not be anyone to call locally who can help.

can anyone provide some insight as to what i may be doing wrong and what i should try.

thank you

[Andre' B]

if i dont stand over the saw and constantly adjust the flow control valve the saw will stop decending or decend too fast

Possible that there is some crude floating around in the oil, plugging up the valve, you then open the valve some and let the bit go thru.

You could try flushing the system out and putting clean oil back in.

[timmydabull]

i dissasembled the hydraulic cylinder flushed everything out with mineral spirits and then reassembled it with a new flow control valve.

it is possible that may be it but i have cleaned it the best i can. ps i used light hydraulic fluid to replace the oil in the cylinder.

thank you for the suggestion.

[masonbcaldwell4]

I know that the usual speed for 6061 is around 200-230 fpm, and while this should have nothing to do with your downfeed rate, it might save a blade or 2....

[Geof]

......ps i used light hydraulic fluid to replace the oil in the cylinder.......

If the cylinder did have just regular lube oil in it and you replaced it with proper hydraulic fluid this could be the problem. Some seal material that is resistant to lube oil is not resistant to hydraulic fluid, and vice versa.

[timmydabull]

what type of fluid would you reccomend?

thank you

[timmydabull]

I know that the usual speed for 6061 is around 200-230 fpm, and while this should have nothing to do with your downfeed rate, it might save a blade or 2....

i will check on that

thank you

[Geof]

what type of fluid would you reccomend?

thank you

Whatever was in there originally, providing it was what the manufacturer recommended.

[Scanfab]

What TPI do you have on the blade, 6-8 per inch? Over 7 inches you have 50 teeth engaged with a cutting force of saw 100lbs, each tooth only cuts with 2 lbs-not enough to dig in a proper manner. Check what kind of chips leave the blade/part-dust and glitter?! Get a blade with only 2-4 teeth per inch, and no problems on a long engagment cut like that.

For long plate cuts of 12" I put 1" dia stock under the piece to be cut next to the solid jaw elevating the part to an angle. Band engagmennt is never more than 4-5 inches at any time, works like a charm. One inch lift will not cause the stock to pop up from the vice.

The saw is still a CNC machinists best machine- All my CNC machines are working against me, but at least the saw pulls to my side!!

[JoeFin]

Morse Variable Tooth blades work best for me

[HuFlungDung]

What TPI do you have on the blade, 6-8 per inch? Over 7 inches you have 50 teeth engaged with a cutting force of saw 100lbs, each tooth only cuts with 2 lbs-not enough to dig in a proper manner. Check what kind of chips leave the blade/part-dust and glitter?! Get a blade with only 2-4 teeth per inch, and no problems on a long engagment cut like that.

For long plate cuts of 12" I put 1" dia stock under the piece to be cut next to the solid jaw elevating the part to an angle. Band engagmennt is never more than 4-5 inches at any time, works like a charm. One inch lift will not cause the stock to pop up from the vice.

The saw is still a CNC machinists best machine- All my CNC machines are working against me, but at least the saw pulls to my side!!

I agree. Use a 3-4 varitooth. You should be able to cut that in under 5 minutes. My homemade bandsaw (only 1/2hp) will cut a 5" round in 5 minutes using a coarse blade like that, a bigger saw should be faster. Coolant is mandatory to prevent blade plugging when cutting a long drag.

Try adjusting the downfeed cylinder whilst cutting air. Determine what setting will allow the saw to descend within 5 minutes. Then cut for real at that setting. I wouldn't be surprised if you could be even more aggressive once you get the hang of it. The band should be okay at 400 fpm if it is bimetal.

[timmydabull]

thank you guys for your replies,now i know what i should expect in terms of cutting time feed speed etc.,i have a 2-3 blade from lenox coming in mon am,and i will check with the manufacture to see what fluid to use in the cylinder.

the blade i have in there now is a 5-8 starrett it broke and i ordered the 2-3 last week,i will order a vari tooth to start using once this blades has served its duty.

i have tried a few 3-4 but that was before i got the cylinder cleaned out and a new flow control valve installed and working sufficiently,so that may be why they might not have worked correctly.

once again thank your for your help and assistance.

[timmydabull]

i have been doing some research on calculating feet per minute with minimal luck

the electric motor turns 1735 revelution per minute
the drive pulley is 5 inches and the wheel pulley is 5 inches for a 1 to 1 ration (this runs through a gearbox before the band wheel and i see no adjustment for speeds so i dont know what to make of it)

the bandwheel is 15 inches in diameter

[timmydabull]

i came up with 462 feet per minute using the formula rpm x 4 divided by bandwheel size equals feet per minute.

given this is correct i will try the new blade tomorrow at the feed rate of 5 minutes per cut. and see how well she fares

thank you

[DareBee]

A 2-3 blade (of good quality) will take less than 2 minutes in 7" 6061. I would say my S20 will knock that off in under 3min using a 4-6 blade (which is too fine) and we never bother to change the SFM (We do too much variety), it is unlikely my saw has been changed from 220ft/min in over 10 years.
I cut 13" 6061 with no issues using a 4-6. If I had a bunch of solid aluminum to cut I would defiantly get 2-3 blade to use.

HydMec factory oil is Mobil SHC632 (viscosity 10 Hydraulic)

[timmydabull]

tried it again today with a lenox lxp blade 2-3 tooth and same thing cut 2 pieces of material now it wont cut,it hangs up in the material and the blade jumps off.

i guess i am going to buy a new saw,tired of messing with this one

[timmydabull]

well i decided to sell this saw and purchase a new one,anyone who may be interested in this puppy it is listed on ebay and $3000 will get it,maybe you will have better luck with it
the ebay listing is here

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220375332857

i called cosen today and they have a fully automatic saw AH250H for $16,000 that will suit my needs just fine,does anyone have any other suggestions in this price range?

thank you
tim

[Scanfab]

DON'T DO IT, the ebay one.! For $2999 I bought my 17" X 12" from enco, and the band assem. pivots up to 45' for miter cuts. 3 phase, coolent, ext. For $2199 they had same model without mitering..
Im totally happy with my NEW band saw from them..

[Scanfab]

Heh, misunderstood the last post, my bad..
A chinese co quoted me a 250mm full auto bandsaw for $7500, also I was looking at a cosen model for about $14000. Think I like the price on the chinese model, has same cutting capacity as the cosen 250..

[timmydabull]

the only chinese model i found online was a WAY TRAIN INDUSTRIES CO., LTD. they had a very nice saw.

if you can find the one you have i will be happy to look at it.

for the record i dont really like chinese stuff,i have had a chinese lathe for 13 years and to ths day i have to walk over to the breaker and turn it on to make it run(cant read chinese electrical diagram) and i like the idea of having a local company to call when i need help.

this is the main problem with the hyd mech saw i have now,i called hyd mech and they refused to deal with me direct,working thru the local dealer wasted 2 weeks of my time,then talking directly to hyd mech was less than impressed with the guy on the phone,basically no support whatsoever.

and i have no one in the yellow pages to call to come out and set my saw up for me to work efficently as i dont know what i am doing(obviously)

i have always been in the frame of mind to buy the best money can buy and brand new that way i can have it delivered set up to provide the solutions i need and for help when i need it.

i tired to cut corners on this deal and reconfirmed why i should always buy new from local source.

whats funny is i barely could scrap up the money to get this saw but after seeing the savings cutting my own material and the thousands of dollars i lost in the last 2 weeks messing with this this a $20,000 saw sounds like a great deal right about now.