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lowcountrycamo
06-12-2012, 10:01 PM
My atlas 12 suffered from much vibration and a small motor that bogged down at a cut deeper than 10-15 thou. So I poured a 3 piece foundation mortaring them together with precision grout sold at HD. Adding up the 15 bags I added over 1000 lbs. At each step I was careful at squaring and leveling all parts. My method was to first pour 2 bases. When dry I leveled/shimmed and lined up in place and packed grout aroud shims. When shims were dry I removed and fill with more grout. Each piece was leveled 3 point. When base was dry and in place I set upper mould on base and poured that in place. After dry I flipped slab over, leveled/shimmed 3 point and again filled with grout. I drilled and epoxied all thread at 3 locations to secure lathe. Concrete always creeps while drying so I still had to level and shim lathe on base despite careful construction.

I then bought 2 hp dayton 1 phase motor from my local scrap yard for 19 bucks. What a deal. Mounted that on the wall behind lathe to isolate vibration.

Also bought wedge tool post from cdco which I really like. With these upgrades my lathe performs much better. I dont know what is normal for other lathes but I can take a 25 thou cut in annealed rod with a feed of .002 per rev at about 200 rpm, reducing diameter by .05 each pass. At more than .025 belt slips. Little vibration and no chatter so far.
http://www.lowcountrycamo.com/images/myAtlas/1.jpg
http://www.lowcountrycamo.com/images/myAtlas/2.jpg
http://www.lowcountrycamo.com/images/myAtlas/3.jpg
http://www.lowcountrycamo.com/images/myAtlas/4.jpg

914Wilhelm
06-12-2012, 10:11 PM
That looks solid! I've always wondered if there was any utility in filling the base of a Bridgeport style mill base with lead shot or non shrinking grout. Would it be stiffer and deader or just heavier?

lakeside53
06-12-2012, 10:18 PM
If you even want better performance, ditch the compound. Make a steel block the correct height for your tool post. Obviously you'll need the compound now and then, but you'd be surprised how much the light compounds "flex" and allow chatter.

Your belt shouldn't be slipping. Might want to look at that.

Elninio
06-12-2012, 10:21 PM
why didn't you just cast the stand into the lathe?

lowcountrycamo
06-12-2012, 10:27 PM
why didn't you just cast the stand into the lathe?

I thought about that but was uneasy about making it that permanent. However, my first lathe was a craftsman 109 that was a pos and I filled the entire bed with precision grout and it suddenly became usable. I think there is much benefit in using grout. EG would be better I guess but much more expensive.

bytewise
06-12-2012, 10:37 PM
I found on my 9" atlas that some of the pulleys and the chuck were badly out of balance. I started at the motor and static balanced each pulley etc. The final result was very satisfactory. I strongly suggest you look for the source of the vibration.

lowcountrycamo
06-12-2012, 11:50 PM
You added weight to balance? I have seen lead tape for tennis raquets.

caveBob
06-13-2012, 12:14 AM
That looks solid! I've always wondered if there was any utility in filling the base of a Bridgeport style mill base with lead shot or non shrinking grout. Would it be stiffer and deader or just heavier?

Here's an article that I bookmarked one day..:

Epoxy Granite Filling an Industrial Hobbies RF-45 Mill for Vibration Dampening and Rigidity (http://www.cnccookbook.com/CCMillEpoxyFill.htm)

Forrest Addy
06-13-2012, 12:32 AM
Great remedy. Even honkin' big production lathes benefit from a stiff sturdy foundation.

I'd be interested in a report on performance improvement.

My experience (I know: yada yada yada) leads me to think that improvement will depend in great deal on the condition of the machne. If the machine is worn you may see improvement but not much. Masses of concrete won't cure wear. A similar lathe in good condition may benefit more.

I would definitely reccommend this solution for those bench lathe owners whose machines are mounted on flimsy sheet metal or wood. The mass and stiffness improvement will be significant. If a concrete stand or foundation is not coming to your shop (it IS a job) I suggest a STOUTLY built welded structual steel bench. Stout does not include used water pipe, slotted steel handimetal, office furniture or retaurant tables. That said those owning beefier than Atlas lathes who remount them on stout massy work benches will see some but probabky not the same level of improvement.

philbur
06-13-2012, 03:38 AM
You should be able to do way better than 0.025". You need to looking into the issue of the slipping belt.

Phil:)


I dont know what is normal for other lathes but I can take a 25 thou cut in annealed rod with a feed of .002 per rev at about 200 rpm, reducing diameter by .05 each pass. At more than .025 belt slips. Little vibration and no chatter so far.

quasi
06-13-2012, 05:15 AM
I believe Carla on the P.M site made reference to a U.S. Government WW2 pamphlet that had instuctions for "beefing up" bench lathes for small shops doing war production.

vpt
06-13-2012, 10:17 AM
Nice job! I know a heavier sturdier bench would also improve my 10" atlas but I have other things to work on. It does what I need it to do and for now that is enough for me.

I also agree that it should take more than .025". My "stock" 10" will take .025" out of 4130 all day long.

rythmnbls
06-13-2012, 10:25 AM
I would definitely reccommend this solution for those bench lathe owners whose machines are mounted on flimsy sheet metal or wood.

+1 on Forest's comment.

I have a grizzly 10"er on a concrete slab. Photo in this thread here. http://bbs.homeshopmachinist.net/showthread.php?t=44193

It makes a difference when machining larger diameter parts. The motor will usually just stall if the DOC is too great instead of chattering, and parting off is drama free.


I believe Carla on the P.M site made reference to a U.S. Government WW2 pamphlet that had instuctions for "beefing up" bench lathes for small shops doing war production.

This is where the idea for my bench came from. The thread is a sticky in the Monarch sub forum entitled "Not Monarch, But Useful Info Just the Same"

Worth a read.


Steve.

rohart
06-13-2012, 07:05 PM
If you tension that belt and it pulls the concrete table over backwards, it'll be the devil's own job to get it back up !

I can't see what kind of belt it is. If you're using a flat belt, the delight is that it does slip at the merest hint of a crash. If it's a V-belt, you could go for a pair of belts with double pulleys, and that would reduce vibration further - any variation of belt thickness, and thus tension, would be halved.

There's enough room there to fabricate an idler on a hinge with a long lever. Whenever you want to up the tension, engage 'extra force' with the lever.

Be careful you don't introduce stresses into the headstock with the rear mounted motor. Belt driven lathes used to be driven from vertically above, and nowadays are driven from vertically below or from a motor mounted on the headstock itself. Rarely does the tension of the belt have to be transmitted down to the base through the mounting bolts and the headstock. Not that anything's going to break, but when you're considering alignment it may become a factor.