Is it my turn? Anything to do with lathes, mills and other shop tools

[gggGary]

Need to true up the ways of your lathe. No problem…

https://www.facebook.com/share/v/1DD6ymK4yC/?mibextid=wwXIfr

And that lathe is ready to sell...............

Was using these while measuring cams. Were in Dad's tool chest.

Took a while for the lightbulb to go on. After looking they are both Brown and Sharp but one block is marked No 24 the other No
27

who knows whats up with that, guess they must have machined the V groove in sets and these are not a matched pair. grr
Yeah went on fleabay and there's Cat No 750B singles with numbers from 20 to up in the hundreds.

Used some shims to get the measuring done but was thinking I could set them up in the mill, a grinding wheel in the spindle with the head rotated to 45 degrees? the depth/height of the V doesn't matter just that it's is consistent end to end and block to block. These are hard steel, good job for a surface grinder IF I had one.

 

[Jim]

thinking I could set them up in the mill, a grinding wheel in the spindle with the head rotated to 45 degrees?

Any reason you can't just take a cut off the bottom? Be much easier than cutting the Vee.
Take a thou or two off the bottom to level the Vee, then take some off the top to even the blocks up.

Remember, I'm just an amateur hack, but cutting perpendicular seems a bit easier than trying to jig up at 45°

 

[siscoken]

Turned a couple of wheel adapters for my truer / balancer out of aluminum round stock

 

[gggGary]

Any reason you can't just take a cut off the bottom? Be much easier than cutting the Vee.
Take a thou or two off the bottom to level the Vee, then take some off the top to even the blocks up.

Remember, I'm just an amateur hack, but cutting perpendicular seems a bit easier than trying to jig up at 45°

Yabut? All the other dimensions are an exact match? I can tilt the head so both v blocks clamp in the vise at once. Just a hacker.

 

[atom4488]

So here is my go at making a solid toolpost for my Logan 820. It is a two-piece fabrication, with the base being cut from 3/8" plate and the top machined from a piece of 3" round stock I had around. No exotic steels here, just basic cold-rolled barstock. The two pieces are TIG-welded together before being trued as an assembly. The existing compound rest attachment consists of two t-bolts; the base plate is drilled for either two or three baseplate attachment bolts, the thought being that adding a third t-bolt will make the attachment more rigid and less likely to chatter in a fore-aft plane. The third bolt remains to be made. If I recall, they are cut from a piece of 5/8" square barstock.

No test cuts as yet, however I intend to do a back-to-back comparison of a parting-off operation to see whether I have actually improved anything!

View attachment 363336View attachment 363337View attachment 363338View attachment 363339View attachment 363340

So the parting-off test results are in, a little disappointing I must say.

• I first tested the parting operation with the compound installed, set first in-line with the carriage and then at right angles to the carriage. Compound gibs fully locked down to eliminate any possible movement. The test piece was 1.50" aluminum round barstock. Basic HSS parting blade, freshly sharpened, with the blade height correctly set. Significant chatter at all spindle speeds, with extremely slow hand feed. Unacceptable for all practical purposes.
• I then mounted the solid tool post, re-adjusted the blade height and got somewhat reduced chatter, but not nearly enough to call it acceptable.
• The previous two tests were done using a 6" three-jaw chuck which is quite massive. The outer end of the jaws are 5.3875" from the shoulder of the spindle. I replaced the chuck with another 6" chuck, that is much less massive. The jaws are 1.875" from the spindle shoulder. Manually feeding the blade resulted in no discernable chatter at all, at any of the three spindle speeds available of the Logan. Encouraged, I tried using the carriage power feed. Guess what, it readily cut at any of the three spindle speeds with power feed. I then tested the same setup but cutting .500" mild steel round stock. Much to my surprise, it cut readily and cleanly with power feed at all three spindle speeds.

The obvious conclusion is that while the solid tool post did help reduce chatter, most of the improvement came from the reduced spindle "overhang". I had read something to that effect elsewhere. Unfortunately, the smaller chuck has significant run-out, however that becomes irrelevant if the workpiece is of smaller diameter than the raw stock and is eventually parted-off from the stock that is held in the chuck. Now shopping for a new "shallow" chuck!

 

[atom4488]

So the parting-off test results are in, a little disappointing I must say.

• I first tested the parting operation with the compound installed, set first in-line with the carriage and then at right angles to the carriage. Compound gibs fully locked down to eliminate any possible movement. The test piece was 1.50" aluminum round barstock. Basic HSS parting blade, freshly sharpened, with the blade height correctly set. Significant chatter at all spindle speeds, with extremely slow hand feed. Unacceptable for all practical purposes.
• I then mounted the solid tool post, re-adjusted the blade height and got somewhat reduced chatter, but not nearly enough to call it acceptable.
• The previous two tests were done using a 6" three-jaw chuck which is quite massive. The outer end of the jaws are 5.3875" from the shoulder of the spindle. I replaced the chuck with another 6" chuck, that is much less massive. The jaws are 1.875" from the spindle shoulder. Manually feeding the blade resulted in no discernable chatter at all, at any of the three spindle speeds available of the Logan. Encouraged, I tried using the carriage power feed. Guess what, it readily cut at any of the three spindle speeds with power feed. I then tested the same setup but cutting .500" mild steel round stock. Much to my surprise, it cut readily and cleanly with power feed at all three spindle speeds.

The obvious conclusion is that while the solid tool post did help reduce chatter, most of the improvement came from the reduced spindle "overhang". I had read something to that effect elsewhere. Unfortunately, the smaller chuck has significant run-out, however that becomes irrelevant if the workpiece is of smaller diameter than the raw stock and is eventually parted-off from the stock that is held in the chuck. Now shopping for a new "shallow" chuck!

- third T-bolt in the making


- test cut with compound showing chatter-marks in the cut



- no chatter at all with the shallower chuck


-same chatter-less cut in steel

 

[Jim]

Nice!!

 

[gggGary]

View attachment 363560View attachment 363561
- third T-bolt in the making

View attachment 363562
- test cut with compound showing chatter-marks in the cut


View attachment 363563
- no chatter at all with the shallower chuck

View attachment 363564
-same chatter-less cut in steel

Put a dial indicator on the chuck and lever it up with a 2X4 on the ways? same with end play.
Your spindle rides on ball bearings.
I had amazing results removing and cleaning the bearings on an old mill with a "jumpy spindle", removed, cleaned regreased and preload set, a .0005" indicator wouldn't even twitch.
I've seen some guys R&R headstock bearings with good results on machinists forums.
The manual with headstock remove install instructions is available for the logan.
also worth a mention in the manual are belt tension settings.

 

[gggGary]

PS @atom4488
Center grinding a three jaw to regain concentricity is a thing, it takes some fixturing but seems like a reasonable project.

 

[atom4488]

Put a dial indicator on the chuck and lever it up with a 2X4 on the ways? same with end play.
Your spindle rides on ball bearings.
I had amazing results removing and cleaning the bearings on an old mill with a "jumpy spindle", removed, cleaned regreased and preload set, a .0001" indicator wouldn't even twitch.
I've seen some guys R&R headstock bearings with good results on machinists forums.
The manual with headstock remove install instructions is available for the logan.
also worth a mention in the manual are belt tension settings.

@gggGary, thanks for the suggestion...will check out the axial and end play at the earliest opportunity and report back.

PS @atom4488
Center grinding a three jaw to regain concentricity is a thing, it takes some fixturing but seems like a reasonable project.

Tried that and made it worse! I need a much better die-grinder (bearings and collet) and probably a better means of holding the die grinder in the tool post.

 

[Jim]

Tried that and made it worse! I need a much better die-grinder (bearings and collet) and probably a better means of holding the die grinder in the tool post.

Read back through this thread. If I'm not mistaken, @Downeaster (pretty sure ) has a pretty slick method of center grinding the chuck.

 

[Wagner73]

Thanks for the heads-up on this! I looked at the details online and ended up buying one. Not necessarily to use as they recommend (as a substitute for jackstands, etc) but for belt & suspenders and/or a quick check safety device.

For cars with limited jacking points - which are most any later model cars (they show sports cars, but it's a ton of others as well) - these work perfectly. A bit spendy but high quality.

https://rennstand.com/?gad_source=1...kKi3bR6Fd0ISAYLoTQ8gpv7SKxd59EwcaAqyMEALw_wcB

 

[Downeaster]

Read back through this thread. If I'm not mistaken, @Downeaster (pretty sure ) has a pretty slick method of center grinding the chuck.

Yup. Details here

 

[atom4488]

Yup. Details here

Thanks DE! Read through your post and have also watched other videos on the subject. The solution proposed by Mr. Pete/Tubalcain is not possible on the chuck in question as the jaws do not have a bolted-on separate top jaw. The ring solution to take up the slack in the scroll/jaw engagement will therefore not work. I will revisit this to devise another solution.

 

[atom4488]

Read back through this thread. If I'm not mistaken, @Downeaster (pretty sure ) has a pretty slick method of center grinding the chuck.

...pretty good memory there, @Jim! Thanks!

 

[Jim]

...pretty good memory there, @Jim! Thanks!

Remember what?

 

[Bjorn]

@gggGary, thanks for the suggestion...will check out the axial and end play at the earliest opportunity and report back.

Tried that and made it worse! I need a much better die-grinder (bearings and collet) and probably a better means of holding the die grinder in the tool post.

Here is how I believe you should grind or hard turn your jaws:

You make slots in your jaws, make a ring that fits it. This way you make sure the jaws are preloaded/ tilted in the same way they normally hold parts.

Some of my findings regarding parting in a small lathe: I've tried all the types of toolholder, from grinding a HSS out of a blank, the pre ground HSS types, carbide blade style. But I've settled on this type:

Not this exact model, but this style, with the smallest commercial available insert width. And the trick seems to be: high cutting speed (rpm) and feed rate. All with lube of coarse. I seems like this will force the chip up in itself, due to the chip breaker geometry.


You can find them reasonably priced on the industrial Chinese websites like Ali.

 

[atom4488]

Here is how I believe you should grind or hard turn your jaws:
View attachment 363678

You make slots in your jaws, make a ring that fits it. This way you make sure the jaws are preloaded/ tilted in the same way they normally hold parts.

Some of my findings regarding parting in a small lathe: I've tried all the types of toolholder, from grinding a HSS out of a blank, the pre ground HSS types, carbide blade style. But I've settled on this type:
View attachment 363679
Not this exact model, but this style, with the smallest commercial available insert width. And the trick seems to be: high cutting speed (rpm) and feed rate. All with lube of coarse. I seems like this will force the chip up in itself, due to the chip breaker geometry.


You can find them reasonably priced on the industrial Chinese websites like Ali.

Haven't had much time to fool around with this, so I have not done the leverage test as suggested by @gggGary nor have I had a chance to try truing the shallow chuck again. I did examine the jaw structure of the shallow chuck and have found that I can tighten the jaws on a ring about 1.5" in diameter and still have enough clearance to grind the jaws with a stone < .75" in diameter. That will probably be my next step, after making a QCTP holder for a die grinder. I noted the carbide parting tool holder referred to by @Bjorn and made a mental note to acquire a similar one that I had but broke when chattering away on a bad cut! I still have a box full of the inserts it uses. Nothing but fun and games!

 

[gggGary]

I noted the carbide parting tool holder referred to by @Bjorn and made a mental note to acquire a similar one that I had but broke when chattering away on a bad cut! I still have a box full of the inserts it uses. Nothing but fun and games!

That was my experience with a chinese carbide insert cutoff holder also, insert holding just wasn't reliable. Had a couple messy failures, the insert support jaws bent, MEH.

I then tried this HSS cutoff tool that clamps in a standard holder.



I'm MUCH happier with this. Very similar to the lantern post cutoff tool dad used.
Sharpening on the grinder is a doddle and It cuts well for quite a while between sharpenings. Also easy to make a custom profile for unusual deep slot needs.
I may cut a light V in the top where it's clamped in the tool holder to more positively engage the setscrews and reduce chances of it tilting forward/down.
Nice that stick out can be kept very short to increase rigidity, reduce, eliminate chatter but can be extended as far as needed to wade into deep cuts.

 

[atom4488]

That was my experience with a chinese carbide insert cutoff holder also, insert holding just wasn't reliable. Had a couple messy failures, the insert support jaws bent, MEH.
View attachment 364170
I then tried this HSS cutoff tool that clamps in a standard holder.
View attachment 364167
View attachment 364168
View attachment 364169
I'm MUCH happier with this. Very similar to the lantern post cutoff tool dad used.
Sharpening on the grinder is a doddle and It cuts well for quite a while between sharpenings. Also easy to make a custom profile for unusual deep slot needs.
I may cut a light V in the top where it's clamped in the tool holder to more positively engage the setscrews and reduce chances of it tilting forward/down.
Nice that stick out can be kept very short to increase rigidity, reduce, eliminate chatter but can be extended as far as needed to wade into deep cuts.

I agree that a rigid HSS blade-holder is probably the best way to go. I made this one that goes directly on the compound rest without the QCTP. I have similar experience with the carbide insert holders, in that they are brittle and therefore fragile. My plan is to stay with HSS blades and the small chuck for parts being made that require a parting-off operation as a final step. Machining sure is a fun rabbit hole to dive into, not to mention being a fundamental part of shop operations, for me at least!