Preferred carbide insert brand/s?

[SouthernChap]

We are quit of topic but it shows that using carbide on non rigid desktop hobby lathes can give good results.

Both my lathes are from HBM, a company in the Netherlands that sells hobby level lathes. Both lathes needed a full service and some tweaking right out of the box but are now repeatable and accurate.

• HBM300, 70 kg, 21 mm spindle bore, 80 mm chuck, BLDC 500W, contact angle bearings, 15 years old
• HBM BF290, 300 kg, 38 mm spindle bore, 160 mm chuck, 1.5 kW brushed DC, tapered roller bearings, 6 years old)

Most of the time I use the lathes in CNC mode so I can set the feed, speed and cutting depth accurately and repeatable. In manual mode I can take a 1 mm depth of cut in mild steel (hot rolled) but only because I feed much slower than in CNC mode. The finish however is like the cutting sound, not good. To me, that isn't a surprise because I have done extensive feed and speed testing on both my lathes so I know what to expect.
I can cut deeper than 0.5 mm in steel, but not with a finish suitable for a bearing fit.

My bigger lathe is more rigid than the small lathe but still not rigid. If you look at the picture you see a massive stud for the tool post mount. The tool post it self is flimsy and has a lot of over hang. If you set it at full extension (70 mm range) the overhang increases. I added 4 aluminum studs to support the tool post and that makes a real difference. If I have time, I will replace the whole setup by a solid tool post support. In CNC mode, the tool is placed above the aluminum studs and the gibs are adjusted (locked) to maximize rigidity. That makes things better.
Even if I can't take heavy cuts, I have no problem getting a decent finish on any of the steel (most of is is unknown type) I have in stock and (CNC) turning to 0.01 mm diameter tolerance requires 3 finish passes of the same cutting depth and one measurement before the last finish pass.

Most of the time, I make small ( 3 .. 40 mm) parts (prototypes) so taking heavy cuts isn't a real option most of the time.

HBM BF 290 lathe later version
HBM 300 lathe later version

The tool post setup of the HBM BF290 lathe.

View attachment 505543

So the mini-lathe looks to be the standard Real Bull pattern with a brushed motor.

These really can benefit from a bunch of adjustments and upgrades. Steve Jordan has a lot of videos about improvements that squeeze out about as much rigidity as is possible from the bed, headstock and tailstock design.

Unfortunately Steve's cataloguing of what he covers in the videos via the titles isn't optimal so you do have to watch most of each particular video to catch some of the important information.

Still and all they're worth checking out.

The motor can be upgraded to a brushless motor (Custom Crafter, a member on this forum, offers a whole load of different options and if and when I do the motor on my little 7x, I'll probably get it via him).

Just upping it to a 1HP (750W) motor should give you a fair bit more torque and with the mechanical advantage you have with the hi/lo gearing in the headstock you probably will end up with more torque than the Seig SC3 model which has a brushless motor but no Hi/Lo gear.

Obviously adding extra stiffening parts (like a central shear plate under the saddle between the ways and chunkier rear and front shear plates) like Steve Jordan does, and upping the torque available can't get you beyond the underlying limitations of the rigidity of the bed (the improvements and upgrades just make sure you don't leave any unutilised sources of rigidity on the table, so to speak, so will help), and if the saddle/cross-slide and compound aren't adjusted optimally then there'll still be rigidity issues.

 

[GrifterGuru]

mechanical advantage you have with the hi/lo gearing in the headstock you probably will end up with more torque than the Seig SC3 model which has a brushless motor but no Hi/Lo gear.

And that is why I am rebuilding my Hi/Lo 7x with a brushless motor.

I have lost count of the times I wished I had the Hi/Lo on this SC3. The better torque in "low" would have helped no end on more than a few occasions!

 

[MrWhoopee]

After trying several different cheap economy inserts, I have found that these hold up really well.

https://www.aliexpress.us/item/3256806586857355.html

I am also using the same grade (KT7030) with the same "Nano Blue" coating in the APKT/APMT configuration for milling. I beat the hell out of them, roughing heat treated 5140 (Rc40-42) with a 25mm 3 insert cutter at 660 rpm and .100 DOC. They can take it, piles of blue chips.

https://www.aliexpress.us/item/3256805194224642.html

For threading, the VP15TF grade has become my favorite.

https://www.aliexpress.us/item/3256805935771680.html

 

[GeneT45]

For threading, the VP15TF grade has become my favorite.

https://www.aliexpress.us/item/3256805935771680.html

Is this the same as that included in your auto-retract threading tool? I haven't used it a bunch, but it seems to cut nicely and is holding up fine so far.

GsT

 

[MrWhoopee]

Is this the same as that included in your auto-retract threading tool? I haven't used it a bunch, but it seems to cut nicely and is holding up fine so far.

GsT

Yes, the same insert. Ordering a few more packs today. I trust the threader is working satisfactorily.

 

[SouthernChap]

And that is why I am rebuilding my Hi/Lo 7x with a brushless motor.

I have lost count of the times I wished I had the Hi/Lo on this SC3. The better torque in "low" would have helped no end on more than a few occasions!

That's kinda of what I'm doing at the mo'.

I cracked the one of the bearing seats on the headstock by not paying attention on my hydraulic press when upgrading to angular contact bearings last year.

So I looked for a replacement, but the only headstocks immediately available at the time were for the Real Bull CJ18A (the Weiss WBL1835 headstocks were on backorder and would have been a 2 month wait).

The chap at Amadeal pointed out that the Real Bull headstocks were the same dimension-wise and location of fixtures-wise but came with the Hi/Lo gearing. He said just take out the gearing and plug up the holes and it'll be the same headstock. It was cheaper than the Weiss headstock too.

When it arrived, I removed the gearing (and actually at that point I noticed it was just a little more thicker walled and heavy than the Weiss one, which was nice), installed the bearings and immediately made up some little brass plugs for where the gear shifter body shaft would have entered it and the two bearing seats for the driven countershaft and called it good.

But now I've reinstalled the gearing on the new spindle that I had to buy with the correct longer keyway (my original spindle didn't have the keyway between the bearing journals, and besides, I got the front angular contact inner race firmly stuck on the fillet of the shoulder of the spindle; it literally would not come off, with heat or cooling or anything I tried, the outer race, balls and sealing shield came very readily off, but that inner race was stuck!), made some new spacers out of aluminium and nylon (a bit rustic as regards the OD but the IDs are fine as are the keyways), reinstalled the countershaft and bearings and then realised that I'd mislaid the gear shifter knob.

So I found another suitably OD'd shaft and knob, did the necessary die work. One good thing is that the shaft now protrudes above the headstock so I can see what setting it's on without leaning over.

I did need to replace the motor pulley as the existing one had the wrong pitch and wouldn't work with the shorter toothed belt that I got to go with the pulley on the countershaft. Unfortunately, the pulley that I got, didn't fit the shaft on the brushless motor so I had to drill that out (good excuse to use the coaxial centre finder, I bought just after I got the mill) and file out the keyway to be correctly sized.

So that's all done. I now need to work out how best to maintain the lubrication of the headstock gearing. I'm currently flip flopping between putting oilers (the cap type I reckon) in the top of the headstock, and using way oil, or putting grease nipples in the same place and using grease.

After that, it's just fixing the tach magnet to the shaft, fitting the Hall effect sensor, making a suitably sized hole in the controls box for the tach display and fitting that, reassembly of the change gear assembly and then refitting the electricals.

It'll be nice to have the lathe back up and working.

 

[GrifterGuru]

That's kinda of what I'm doing at the mo'.

I cracked the one of the bearing seats on the headstock by not paying attention on my hydraulic press when upgrading to angular contact bearings last year.

So I looked for a replacement, but the only headstocks immediately available at the time were for the Real Bull CJ18A (the Weiss WBL1835 headstocks were on backorder and would have been a 2 month wait).

The chap at Amadeal pointed out that the Real Bull headstocks were the same dimension-wise and location of fixtures-wise but came with the Hi/Lo gearing. He said just take out the gearing and plug up the holes and it'll be the same headstock. It was cheaper than the Weiss headstock too.

When it arrived, I removed the gearing (and actually at that point I noticed it was just a little more thicker walled and heavy than the Weiss one, which was nice), installed the bearings and immediately made up some little brass plugs for where the gear shifter body shaft would have entered it and the two bearing seats for the driven countershaft and called it good.

But now I've reinstalled the gearing on the new spindle that I had to buy with the correct longer keyway (my original spindle didn't have the keyway between the bearing journals, and besides, I got the front angular contact inner race firmly stuck on the fillet of the shoulder of the spindle; it literally would not come off, with heat or cooling or anything I tried, the outer race, balls and sealing shield came very readily off, but that inner race was stuck!), made some new spacers out of aluminium and nylon (a bit rustic as regards the OD but the IDs are fine as are the keyways), reinstalled the countershaft and bearings and then realised that I'd mislaid the gear shifter knob.

So I found another suitably OD'd shaft and knob, did the necessary die work. One good thing is that the shaft now protrudes above the headstock so I can see what setting it's on without leaning over.

I did need to replace the motor pulley as the existing one had the wrong pitch and wouldn't work with the shorter toothed belt that I got to go with the pulley on the countershaft. Unfortunately, the pulley that I got, didn't fit the shaft on the brushless motor so I had to drill that out (good excuse to use the coaxial centre finder, I bought just after I got the mill) and file out the keyway to be correctly sized.

So that's all done. I now need to work out how best to maintain the lubrication of the headstock gearing. I'm currently flip flopping between putting oilers (the cap type I reckon) in the top of the headstock, and using way oil, or putting grease nipples in the same place and using grease.

After that, it's just fixing the tach magnet to the shaft, fitting the Hall effect sensor, making a suitably sized hole in the controls box for the tach display and fitting that, reassembly of the change gear assembly and then refitting the electricals.

It'll be nice to have the lathe back up and working.

Re the gearing and greasing... I used and will continue to be using the lithium based non-mobile/limited mobility grease I have. stuff is thicker than mollassas and sticks like the preverbial to a blanket.

If you used oil as lubrication, you will have to fully seal the headstock casting so you do not have to deal with oil dripping everywhere since it will spray all over the inside of the casting, pool on the top of the bed and will seep out of any and all minor wicking paths it can. Guess how I know that nugget of information? Yep, I tried it on the lathe I am rebuilding and regretted it, even with ISO 220 way oil with the tackifier. The resultant mess was awful and a real PITA to clean up.

I am still ponndering over the seals for the TRBs I have fitted to the headstock for it and how to keep the darned grease in them.

BTW, does your bed have three or four bolt fixing holes for the head? My head has four bolt fixing, but the bed only had three bolt fixing holes.. Strange but true and soon rectified!

Going to order the motor kit up soon. At least that way, I can get the "basic" test build done of head on, motor mounted with belt in place.

And yes, I got the HiLo from amadeal, along with the large foot tailstock.

Still have to modify the leadscrew and machine the stub-shaft for it.

 

[SouthernChap]

Re the gearing and greasing... I used and will continue to be using the lithium based non-mobile/limited mobility grease I have. stuff is thicker than mollassas and sticks like the preverbial to a blanket.

If you used oil as lubrication, you will have to fully seal the headstock casting so you do not have to deal with oil dripping everywhere since it will spray all over the inside of the casting, pool on the top of the bed and will seep out of any and all minor wicking paths it can. Guess how I know that nugget of information? Yep, I tried it on the lathe I am rebuilding and regretted it, even with ISO 220 way oil with the tackifier. The resultant mess was awful and a real PITA to clean up.

I am still ponndering over the seals for the TRBs I have fitted to the headstock for it and how to keep the darned grease in them.

BTW, does your bed have three or four bolt fixing holes for the head? My head has four bolt fixing, but the bed only had three bolt fixing holes.. Strange but true and soon rectified!

Going to order the motor kit up soon. At least that way, I can get the "basic" test build done of head on, motor mounted with belt in place.

And yes, I got the HiLo from amadeal, along with the large foot tailstock.

Still have to modify the leadscrew and machine the stub-shaft for it.

Okay so it's grease then. I'll look at grease nipples.

My bed had four from the get go. Mine (under the Amadeal branding) was a Weiss WBL1835 when it arrived; it's now a bit of a hybrid. The CJ18A headstock came with four threaded holes too.

What motor did you decide on? Was it the 1.1KW or the 2?

I've got a 750W so I'll leave it for the time being but I would be entirely unsurprised to find that's overstated and is only the input power. Eh, might go for a 1.1KW from Custom Crafter if I haven't bought myself some old English iron before.

 

[GrifterGuru]

Okay so it's grease then. I'll look at grease nipples.

My bed had four from the get go. Mine (under the Amadeal branding) was a Weiss WBL1835 when it arrived; it's now a bit of a hybrid. The CJ18A headstock came with four threaded holes too.

What motor did you decide on? Was it the 1.1KW or the 2?

I've got a 750W so I'll leave it for the time being but I would be entirely unsurprised to find that's overstated and is only the input power. Eh, might go for a 1.1KW from Custom Crafter if I haven't bought myself some old English iron before.

Going with the 1100w/1.1kw kit. I know it will fit and it will be double the power of this SC3.

As for underpowered, the SC3 is 500w (supposedly) and even being brushless, it can be gutless at times and struggles if I try to run a deep DOC using powerfeed. I have always had to go "manual" for deep cuts and even then, it sometimes struggles. Quite annoying and exactly why I want to get my other lathe rebuilt sooner rather than later. I have the major work done on that now anyway (cross slide screw & carrier boss) so just the compound slide screw and the leadscrew to get done. Neither of which will take long to do.

After that, it is a case of waiting for the motor kit, once I order, it before I can then get the rebuilt lathe level, true and aligned to itself.

The SC3 is all fine and well, but I need a lathe I know I can work with and one that will be capable of what I need from it, even in the small form factor and lack of rigidity that is the 7x platform. The SC3 was only ever a "stop gap" to enable me to do the work on the other lathe anyway.

Right now, I don't have the space for any other lathe and I am pushing my luck by going for the Mill that I will be acquiring given where it will be located.