Eyeball Engineering

[rob_b]

Still vote lathe... but lets talk about your mill some more. How much quill travel do you have? Because for cnc to really function at a basic level "for production" you need repeatable height tool holders. The standard for our class of machines is the Tormach TTS. I mainly use ER20 holders and have to retract 3" over the top of my part to do a tool change. Drill chucks need an extra 2" of travel. I'm sure you already have experience with this issue but it will be a real productivity killer. Right now it takes me about 30 seconds chip to chip for a tool change and even that really adds up to a ton of "waisted" time over a long run.

[JohnRobHolmes]

If you are running in house parts , be sure to include $50 an hour to the parts costs to "pay off" the machines. You are a fab house, be real about what your overhead costs should be/ could be. It will ensure that your parts are priced right to pay for tools, insurance, rent, and all the other little costs that you probably don't have to pay yet. But, if you aren't looking at this from a realistic fab shop perspective then you won't be able to grow there either.


Sounds like you want cnc more. I bet you could get crafty and put a lathe on the mill bed and have it all.

[Duuuuuuuude]

Originally Posted by rob_b

Still vote lathe... but lets talk about your mill some more. How much quill travel do you have? Because for cnc to really function at a basic level "for production" you need repeatable height tool holders. The standard for our class of machines is the Tormach TTS. I mainly use ER20 holders and have to retract 3" over the top of my part to do a tool change. Drill chucks need an extra 2" of travel. I'm sure you already have experience with this issue but it will be a real productivity killer. Right now it takes me about 30 seconds chip to chip for a tool change and even that really adds up to a ton of "waisted" time over a long run.

I run the part out from under the quill to do tool changes to keep the head as low as possible. Max height is determined by the tools I'm using. The drill chuck extends 3-4" below the collet, so I avoid using it as much as possible. If I need to drill a hole I have a pin vice for the tiny ones, and otherwise limit myself to short bits that will fit into a collet.

Originally Posted by JohnRobHolmes

If you are running in house parts , be sure to include $50 an hour to the parts costs to "pay off" the machines. You are a fab house, be real about what your overhead costs should be/ could be. It will ensure that your parts are priced right to pay for tools, insurance, rent, and all the other little costs that you probably don't have to pay yet. But, if you aren't looking at this from a realistic fab shop perspective then you won't be able to grow there either.


Sounds like you want cnc more. I bet you could get crafty and put a lathe on the mill bed and have it all.

I charge what I think the market will bear when it comes to production pieces. If, for the time being, that means I have to whore myself out then so be it. I can't yet move fast enough to factor in all costs and bill accordingly.

[JohnRobHolmes]

Just don't short change yourself over the long run with market pricing. Sometimes, items can't be made for a good market price. I don't want to see you working yourself to death at less than minimum wage, because we won't be seeing cool DCW parts for much longer! I'm just trying to make sure you are fair to yourself, it's easy to get into the mindset that parts costs are only your time and materials when there is square footage and machine depreciation that have to be factored in to keep you going for the long term.

[Trubble]

Originally Posted by Duuuuuuuude

I reeeeeeally want a lathe, but a cnc seems more practical at the moment.

Originally Posted by Duuuuuuuude

CNC would also help a ton with making wheels, especially if I add a 4th axis. Lathe operations would happen too.

Well, I like and understand lathes better than I do mills, so my heart wants to put in a vote for a lathe.

But from the outside lookin' in, it's hard to pass up on the fact that a CNC convo can help you with making wheels, but I have a difficult time imagining a lathe being any help with making D-mounts or your Wraith skid risers.

Originally Posted by Duuuuuuuude

I just wrapped up a run of 350+ individual parts. It was such a grind that I don't want to do that again for a long, long time.

Ooooooh, signs of burnout looming on the horizon, that ain't good.

Originally Posted by Duuuuuuuude

With 4 different products, 2 prototypes, and a handful of wheel designs that are all done in-house, I'm constantly looking for ways to shave time on operations. ......... However, DCW funds itself and I need the most bang for the buck to upgrade and expand. Right now that means doing everything myself in whatever time I have to do it in.

I apologize for being as much of a dream-killer as my father was/is, but I'm going to ask these questions anyway.

a) sounds like you're fighting a Herculean effort to keep up. If you pass on the CNC, won't you still have to mount that fight again at some point in the future?

b) If not having the CNC is going to bog you down, no offense, but when do you think you'll have time to teach yourself lathe-work?

Best of luck with your decision, we'll await news of which way you finally went.

[JohnRobHolmes]

Ahh, the problems of a passion turning into work! Very good points made by trubble. As hard nosed as the questions are, they do need to be considered as the main problems. Your time is your biggest asset, and it isn't a failure to hire other machinists to make the designs that you have done up to this point!

[Duuuuuuuude]

Originally Posted by JohnRobHolmes

Just don't short change yourself over the long run with market pricing. Sometimes, items can't be made for a good market price. I don't want to see you working yourself to death at less than minimum wage, because we won't be seeing cool DCW parts for much longer! I'm just trying to make sure you are fair to yourself, it's easy to get into the mindset that parts costs are only your time and materials when there is square footage and machine depreciation that have to be factored in to keep you going for the long term.

Short change is better than no change.

Working myself to death is not an option. I don't depend on whatever income I may make from DCW so I can step away whenever I need to. It is still mostly a hobby, I'm just lucky enough to make a little money at it.

Originally Posted by Trubble

Well, I like and understand lathes better than I do mills, so my heart wants to put in a vote for a lathe.

But from the outside lookin' in, it's hard to pass up on the fact that a CNC convo can help you with making wheels, but I have a difficult time imagining a lathe being any help with making D-mounts or your Wraith skid risers.

Ooooooh, signs of burnout looming on the horizon, that ain't good.

I apologize for being as much of a dream-killer as my father was/is, but I'm going to ask these questions anyway.

a) sounds like you're fighting a Herculean effort to keep up. If you pass on the CNC, won't you still have to mount that fight again at some point in the future?

b) If not having the CNC is going to bog you down, no offense, but when do you think you'll have time to teach yourself lathe-work?

Best of luck with your decision, we'll await news of which way you finally went.

a) I wouldn't say it is Herculean, its just more time consuming that I would like, not to mention incredibly boring. I hate repetitive work. During one of the simpler operations I propped my tablet up on the vice, plugged in some headphones, and watched Netflix for a few hours while I was working.

If I skip the cnc I'll either have to farm big runs out or limit them to small enough quantities to not murder my soul while I make them.

b) Either way I will have to make the time. Summer is always hard to get things done, but as winter approaches, my free time increases quite a bit.

Originally Posted by JohnRobHolmes

Ahh, the problems of a passion turning into work! Very good points made by trubble. As hard nosed as the questions are, they do need to be considered as the main problems. Your time is your biggest asset, and it isn't a failure to hire other machinists to make the designs that you have done up to this point!

Unfortunately and ultimately it comes down to funding. I do not involve my personal finances at all in this venture, so its really my free time that keeps things going.

[BigSki]

Have you given thought about the tooling costs to get a lathe up and functioning vs. doing a CNC conversion to your mill?

[Duuuuuuuude]

Found this...

Big Dog 7 x 14 benchtop Lathe - Big Dog Metal Works

A bit more than the Grizzly version, but comes with things that the Grizzly version doesn't, specifically a 4" chuck.

[EddieO]

I'd look at the Grizzly g0602 lathe. I know its a bit more, but there is a lot more out there for it. More swing, More rigid and in the event you want to convert it to CNC, its probably the most popular lathe to do it on for a consumer. Rob_b has one, as do I. Mine is finally up and running CNC (been a steep learning curve for a CNC newbie).....

Later EddieO

[BigSki]

Originally Posted by Duuuuuuuude

Found this...

Big Dog 7 x 14 benchtop Lathe - Big Dog Metal Works

A bit more than the Grizzly version, but comes with things that the Grizzly version doesn't, specifically a 4" chuck.

I'll share my opinion/experience with a 7 x 14 lathe. I had a MicroMark 7 x 14, it was decent for doing very small parts in plastic and some grades of aluminum. It absolutely sucked at doing mild steel, I was limited to .005-.010 per pass. Parting steel pieces is where I really saw the weaknesses of the design, you had to apply a very minimal amount of pressure to part steel or else the carriage would rock a bit. This is after I upgraded to the better gibbs from my little machine shop. It wouldn't even cut steel before I did that.

I also found myself being limited to what I could work on the machine because of the small swing-over. Other than the "metal" gears of the big-dog lathe, I don't see any differences between it and the micromark version.

I'd go for the 10 x lathe if you can squeeze it into your budget. You won't out grow it nearly as fast and it should be a more stable machine over all.

[Duuuuuuuude]

I have absolutely no need to machine steel. I've only done it a couple of times on my mill just to fool around. Its normally 60% aluminum, 40% delrin.

[BigSki]

Just think about how nice it would be knowing that you could
turn steel if you wanted to.

[Duuuuuuuude]

I don't want to.

[JohnRobHolmes]

The lack of rigidity will limit your cutting of aluminum and delrin too, whether or not you intend on cutting steel. You would have better finishes and longer tool life with the 10x lathe instead of the 7x. It will really show up in the ability to part cleanly and fast without the cutoff blade getting jammed as the lathe flexes. Especially with delrin, it is important to keep the bit moving fast or else the heat builds up locally and starts melting the material. It needs a pretty aggressive feed rate.

If this was just fiddly piddly shop use it wouldn't be a big deal, but since you intend on making stuff it is very important to consider your cut times and tool lifes. Tool life isn't so much about how much material is removed, but how much time "in the cut" is spent. Rigid is fast, and fast saves money.

[JohnRobHolmes]

Originally Posted by EddieO

I'd look at the Grizzly g0602 lathe. I know its a bit more, but there is a lot more out there for it. More swing, More rigid and in the event you want to convert it to CNC, its probably the most popular lathe to do it on for a consumer. Rob_b has one, as do I. Mine is finally up and running CNC (been a steep learning curve for a CNC newbie).....

Later EddieO

I've used this lathe at a local motorcycle fabber's shop. It's very good for the cost, a huge jump in capability for a small jump in price over 7" lathes.

[EddieO]

Originally Posted by JohnRobHolmes

I've used this lathe at a local motorcycle fabber's shop. It's very good for the cost, a huge jump in capability for a small jump in price over 7" lathes.

See, you can't argue something that Holmes and I agree on....it takes cosmic forces for this to occur usually:


They even sell it with a VFD installed now too, so it makes threading and such even easier...The part number is different, its about $300 more.

I have smaller lathes (emco compact 5), while fun for small stuff...the limits of what you can do are a bummer, though they have smaller swing than a 7 inch, they are much more rigid as they are better made than most of the 7 inch stuff out there.

Later EddieO

[Duuuuuuuude]

Originally Posted by JohnRobHolmes

If this was just fiddly piddly shop use it wouldn't be a big deal, but since you intend on making stuff it is very important to consider your cut times and tool lifes.

That's the thing...it kinda is for fiddly piddly shop use. It'll be used to do things that the mill can't do as well as a lathe can. Squaring up wheel blanks, cutting bead grooves, maybe turning down an occasional rod, stuff like that. I'm not going to be doing production runs on it.

I also have to consider space...I'm running out of it if I still want to keep the garage vehicle worthy. A smaller, 100lb rig would be easier to place and move than a larger, 400lb rig.

[BigSki]

Originally Posted by Duuuuuuuude

I don't want to.

Originally Posted by Duuuuuuuude

That's the thing...it kinda is for fiddly piddly shop use. It'll be used to do things that the mill can't do as well as a lathe can. Squaring up wheel blanks, cutting bead grooves, maybe turning down an occasional rod, stuff like that. I'm not going to be doing production runs on it.

I also have to consider space...I'm running out of it if I still want to keep the garage vehicle worthy. A smaller, 100lb rig would be easier to place and move than a larger, 400lb rig.

You will, believe me. Once you have the ability to turn material, the brain starts working overtime on new uses for the equipment.

[JohnRobHolmes]

Even if he doesn't want to turn steel, the first thing a new machine does is make the owner want a bigger machine. I think we are just trying to help him avoid the pitfalls.


So i'm going to say that one size bigger is awesome for fiddly piddly work too! Nothing more satisfying than squaring off a delrin puck with one long streamer of fake fro! 400 pounds isn't much with a proper skid and some steel rollers. I moved my 1200lb machine lathe into the basement with the help of one person and a few 2" pipes. 4" would have been a better choice.