I stripped the T-nuts on my PM-1030V compound

mikey said:
I agree with you that you probably over-torqued those nuts but was it necessary? If the compound is not seated well on the cross slide or if the parts of the compound are not machined for a good fit then things can move, even with a lot of torque on the nuts. If you had to crank down because things slipped in use then its time to evaluate fits because it should not take a lot of torque to lock down the compound. The wrench for mine is 3" long and mine has never moved, even with 0.100" depths of cut in steel.

I would third the plinth idea.
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What brand and size of machine do you have to be taking .100” cuts in steel? Our instructor in school did that on a Bridgeport, but he told us not to exceed .030” on the large domestic machines. Of course, when he wasn’t looking I cut .040” out of curiosity and impatience.

I just saw the word plinth for the first time in my life yesterday, and it was on this forum. It would appear that a plinth is a rigid spacer that is used to mount a tool post without a compound slide. I have a cross slide DRO, but it appears to not involve the compound at all.
 
erikmannie said:
I have never heard of an SHCS; I will Google it. It looks like what happened to me is a common occurrence. I don’t imagine that I am exceeding the capability of this small import lathe by cutting steel. I also plan to cut Grade 5 titanium, so we’ll see if this benchtop 10” can handle it.
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Sorry, SHCS is socket head cap screw, a hex socket screw. So instead of using a bulky open end or box end wrench I simply use a long hex key with a stubby short end.

You should be able to machine Ti 6-4 just fine. I machine Ti often and did even on my old 8x mini lathe. Drilling is what sucks the most. Keep an eye on heat & cutter sharpness. Use flood coolant if you have it. And keep caution not to ignite chips on fire. I caught my current lathe on fire once by a stupid mistake. Wasn't bad & only cosmetic damage that I was able to fix but quickly reminded me not to get careless. Can't put out Ti fires with a normal fire extinguisher.
 
darkzero said:
Sorry, SHCS is socket head cap screw, a hex socket screw. So instead of using a bulky open end or box end wrench I simply use a long hex key with a stubby short end.

You should be able to machine Ti 6-4 just fine. I machine Ti often and did even on my old 8x mini lathe. Drilling is what sucks the most. Keep an eye on heat & cutter sharpness. Use flood coolant if you have it. And keep caution not ignite chips on fire. I caught my current lathe on fire once by a stupid mistake. Wasn't bad & only cosmetic damage that I was able to fix but quickly reminded me not to get careless. Can't put out Ti fires with a normal fire extinguisher.
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It would appear to me that the way my compound mount is set up, I would not be able to get a hex key in there for most of the angles. I can’t even use a box end wrench—I use a 14mm cone wrench. Looking at your photos, you have a circular channel underneath your compound assembly so you always have access to the top of the SHCSs.
 
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erikmannie said:
What brand and size of machine do you have to be taking .100” cuts in steel? Our instructor in school did that on a Bridgeport, but he told us not to exceed .030” on the large domestic machines. Of course, when he wasn’t looking I cut .040” out of curiosity and impatience.

I just saw the word plinth for the first time in my life yesterday, and it was on this forum. It would appear that a plinth is a rigid spacer that is used to mount a tool post without a compound slide. I have a cross slide DRO, but it appears to not involve the compound at all.
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I can cut 0.100" on my PM1127. Not really difficult on the machine unless the steel is really hard. This is 12L14 3/4" bar in 2 steps to 0.030". Very sharp HSS tool.

I have some unknownium that's stupid hard and requires good carbide to cut it. I think I got to 0.080 before things got a bit hot.

IMG_20181009_220928.jpg
 
erikmannie said:
It would appear to me that the way my compound mount is set up, I would not be able to get a hex key in there for most of the angles. I can’t even use a box end wrench—I use a 14mm cone wrench. Of course, if I used a plinth, there would be no angles.
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Ah yes, I forgot that your style compound would swivel & cover the compound nuts instead of the entire base swiveling as one unit.
 
erikmannie said:
What brand and size of machine do you have to be taking .100” cuts in steel?

I just saw the word plinth for the first time in my life yesterday, and it was on this forum. It would appear that a plinth is a rigid spacer that is used to mount a tool post without a compound slide. I have a cross slide DRO, but it appears to not involve the compound at all.
Click to expand...

I have an Emco Super 11 CD, an Austrian 11 X 24 lathe. It is made to a DIN tool room standard, has zero spindle run out, 2 HP motor and can take that 0.100" in steel, 0.200" in aluminum with HSS tools. I can go deeper but I have to slow down a bit to do it. It will also take micro-cuts in the tenths. Nice lathe and definitely not in the same class as an Asian machine. Stefan on Youtube has an older model of the lathe I have.
 
erikmannie said:
Well, now I am taking to asking everybody what material was used for their plinth.
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The base is 7075 aluminum. The plate on the top is ground steel I don't have a spec for. It looks like a low carbon steel of some kind. Precision ground, had a Starrett sticker on the packaging, but the part numbers etc were removed. Post is 12L14, threaded to match the original.
 
mikey said:
I have an Emco Super 11 CD, an Austrian 11 X 24 lathe. It is made to a DIN tool room standard, has zero spindle run out, 2 HP motor and can take that 0.100" in steel, 0.200" in aluminum with HSS tools. I can go deeper but I have to slow down a bit to do it. It will also take micro-cuts in the tenths. Nice lathe and definitely not in the same class as an Asian machine. Stefan on Youtube has an older model of the lathe I have.
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I was jealous of that machine even before I saw that it had zero spindle run out. I am saving up for a MUCH larger PM machine. I hope to one day have a machine where I don’t have to change out the gears to cut different thread pitches.

What I am going to do here is try the Grade 12.9 bolts. If I see any more movement, I will make a plinth. If I want to cut a taper or threads, I guess I will have to temporariliy remove the plinth.

Looking at the size of it, I would imagine that a plinth would have to be mostly aluminum If one is to remove it from time to time.
 
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