Stiff enough??

[TorontoBuilder]

So I wish to solicit opinions because I have little experience with sheet metal assemblies for structural purposes, and I don't want to be this guy.

I need to make a bracket that will hold a lathe countershaft. The shaft will be mounted in two pillow blocks. The shaft will suffer bending forces due to the opposing loads that the assembly must have sufficient lateral rigidity to resist. I hope I used the right terms.

The rear of the shaft will have a timing pulley and belt that goes to a motor slung beneath this bracket and the heavy duty 1/2" thick cast iron bracket it shall sit on. The near side of the shaft will have a dual vee pulley and belt going to the spindle mounted in the head stock above.

Below is am image of the main heavy duty bracket and the ghost image of where the variator normally mounts. My bracket is to replace the variator and hold a new shaft at the same centerline height.

So, after being publicly shamed for proposing having a part made instead of taking the DIY approach (I'm not really complaining because I am both cheap, and I prefer the DIY approach) I think I can actually fabricate this part with the resources I have at my disposal... which are, metal band saws, mig welder, nibbler that can cut 12 gauge carbon steel sheet, and a box bender. Maybe just maybe I could manage 10 gauge.

So my questions are these... will 12 gauge sheet be rigid enough with just a simple top hat shaped bend as show? Or failing that, will 12 gauge sheet steel work if I welded in two gusset plates on the underside of the bracket and perhaps doubled up the thickness of the flange by welding another strip of 12 gauge on top of the flanges?

I wish i had access to a heavy duty spot welder so I could do more sheet metal work because I can think of a thousand projects to do

 

[140mower]

Can't the pillow blocks mount right to the existing structure? What if you make an intermediate plate to go between the two?

 

[TorontoBuilder]

Can't the pillow blocks mount right to the existing structure? What if you make an intermediate plate to go between the two?

Yes I likely can mount the pillow blocks right to the existing bracket with an intermediate plate to match the existing mounting holes for the variator. This will necessitate the replacement of the two long vee belts with some knew yet to be ascertained length. That wont prove difficult.

However, the timing belt replacement may be much more difficult, as the angle of the tooth engagement may likely become too shallow and result in premature tooth wear on the belt. I'll toy around with the in fusion to determine my angles, tooth engagement and required belt lengths...

That said, I don't think the bracket will cost much or be too hard for me to fabricate myself after all. I think I'd add gussets regardless so I can practice welding sheet steel. I know a guy with a sheet metal shop that will likely let me borrow a brake locally too.

 

[Darren]

Can't you take the guts out of the variator housing and make a through shaft?

 

[TorontoBuilder]

Can't you take the guts out of the variation housing and make a through shaft?

Damn dude... that is inspred.

Yes, in fact yes I can absolutely do that. IF I decide to give up on the variator refurbishment as a long term goal I can leave things as they are, or I can make all the repairs and then pull the variator and again reassemble to return to original spec.

I'm going to expound on this idea in my other thread with the variator issues so it is all in a single thread, but thanks for that idea!

Okay people you can still replyin regards to the stiffness of the proposed assembly as I am still undecided for the moment. I'll be modeling up a single shaft that can replace the split shaft in the variator now

 

[TorontoBuilder]

Can't you take the guts out of the variator housing and make a through shaft?

ps...

I have read every thread on the internet with regards to surplanting the non-operable variator in a chipmaster lathe favour of a VFD. There have been a few comments about countershafts and how to bypass the variator but not one comment mentioned such an options and clearly I allowed myself to become myopic focusing on the single solution rather than the big picture. So kudos to you sir for outthinking all the others.

 

[Susquatch]

Nice @Darren. Very nice.

@TorontoBuilder - I'd abandon refurbing the variator. Why would you ever go back to that after using a VFD? If they had VFDs when that machine was built, it would never have seen a variator.

 

[TorontoBuilder]

I see
"best answers" section in everyones profiles, but I can't seem to find a way to award a best answer. Is that a function that has been enabled here

 

[TorontoBuilder]

Nice @Darren. Very nice.

@TorontoBuilder - I'd abandon refurbing the variator. Why would you ever go back to that after using a VFD? If they had VFDs when that machine was built, it would never have seen a variator.

The variator maintained torque at lower speeds better than a VFD can. A variator looks really cool...

But 8K rebuild estimates are insane. I could buy a new lathe for that. Or 2 sets of bearings.

I'm going with Darren's solution all the way and hope to be running asap

 

[TorontoBuilder]

The variator maintained torque at lower speeds better than a VFD can. A variator looks really cool...

But 8K rebuild estimates are insane. I could buy a new lathe for that. Or 2 sets of bearings.

I'm going with Darren's solution all the way and hope to be running asap

OH and I hope to get a 5 HP inverter ready wattsaver motor that has a good CT speed range and new TECO VFD at a later date to replace the original 440 volt 3 phase motor. My two other motors lack a mounting plate they only have a faceplate mounting option.

 

[Susquatch]

The variator maintained torque at lower speeds better than a VFD can.

Not buying that. With the right motor, a VFD will maintain full rated torque all the way to zero. Now, if the Variator multiplies torque like a gear set would, then that's a different story.

A variator looks really cool...

Yes, I'm buying that!

Still, I'd "UPGRADE" to a VFD.

 

[Darren]

Glad to help.

For that machine, because of the 3000+ rpm spindle, you will want an external braking resistor that the Teco L510 series does not have. I believe the E510 does, and would be a much better choice.

As far as maintaining torque/HP at lower RPM, don't worry about it at all if using a 5hp motor. My 3hp Emco V13 will take some heavy cuts in high gear at 20ish hz. It is not an inverter rated motor, as far as I know. Probably not, as the machine was built in 94....but its Austrian, so who knows.

Does that machine have a hi/lo box, or is it all done with the variator?

either way, use the variator handwheel to control the pot for the vfd

 

[Susquatch]

I see
"best answers" section in everyones profiles, but I can't seem to find a way to award a best answer. Is that a function that has been enabled here

It's here someplace. I've seen it used. But I've never figured out how to use it. If ever a post deserved that, it was @Darrens!

 

[Darren]

don't worry about the best answer business

 

[TorontoBuilder]

Glad to help.

For that machine, because of the 3000+ rpm spindle, you will want an external braking resistor that the Teco L510 series does not have. I believe the E510 does, and would be a much better choice.

As far as maintaining torque/HP at lower RPM, don't worry about it at all if using a 5hp motor. My 3hp Emco V13 will take some heavy cuts in high gear at 20ish hz. It is not an inverter rated motor, as far as I know. Probably not, as the machine was built in 94....but its Austrian, so who knows.

Does that machine have a hi/lo box, or is it all done with the variator?

either way, use the variator handwheel to control the pot for the vfd

The A510 does IIRC. I see the motor at auction so If I can get it I will... of course I'll be keeping the handwheel, I'm already thinking how to mount it so as to control the pot. I'm going to buy a large pot to suit the application and put a matching gear on it I think.

I have an external resister already from another motor control panel that I believe is close to the one westinghouse recommended

You deserve a best answer.

I dont know for sure about the high low. I believe so but I can't say with 100% certainty because they came in several iterations, and some hand wheels hand hi lo indications but mine does not IIRC

 

[Darren]

the 10ee uses a chain drive to move the pot with the factory dc drive. When i was thinking of doing a VFD retrofit, it looked like a chunk of rubber hose could be used to move a much smaller standard potentiometer.

 

[TorontoBuilder]

I now know definitely that there is a lever "C" that changes between high and low speed in the head stock.

In low speed the spindle is fed through the internal gearing. In the high speed range the gearing is disengaged and the spindle is driven directly from the clutch by a timing belt... This is how they can hit 3000 rmp

 

[Darren]

that might be threading vs feeds like the 10ee, not actually a motor/variator/gear reduction to the spindle. Either way, a 5hp motor and VFD will provide the needed speed range, but bonus if it does have a 'backgear'

 

[TorontoBuilder]

the 10ee uses a chain drive to move the pot with the factory dc drive. When i was thinking of doing a VFD retrofit, it looked like a chunk of rubber hose could be used to move a much smaller standard potentiometer.

The current system is complex and has a clutch to keep idiots like me from causing damage by turning wheels when motors are not running....

I can gut much of that and just retain the external wheels, one short shaft and a gear, as well as the mounting plate that fixes the wheel assembly to the variator shell. The idea to retain the variator shell is brilliant because I have very little to adapt in order to make this all work.

I'll mount a plate between the variator shell and mounting bracket so I can mount the pot to the plate and bob's your uncle as they say

 

[TorontoBuilder]

that might be threading vs feeds like the 10ee, not actually a motor/variator/gear reduction to the spindle. Either way, a 5hp motor and VFD will provide the needed speed range, but bonus if it does have a 'backgear'

It does... so I'm now especially happy to know my motor selection become much broader fi I miss my auction motor