[LazyMan]

How much would you bid on something like this for 30 pieces and 100 pieces. I'm not a full time shop and never do turning work. I really don't know how to quote more than a few pieces. I generally don't get much turning work but don't want to turn this down because I don't want to lose potential business.I'm considering buying a rapidturn just for this job. Part is Delrin. Advise please.

[s2jesse]

did you mean to post a picture or more info?

[LazyMan]

I suppose that was pretty important . Added the pic, thanks.

[flick]

If you really want the work, quote it as if you had the ideal piece of equipment, then make it on whatever you've got. On a small turning center with a spindle bore to swallow that 1.5 inch material, that job is a 2 minute cycle time, tops. Around here you'd charge 1 hour for 30, 3 hours for 100, plus an hour to setup, plus material if the customer isn't supplying it. The ideal, small turning center to run that job would go for about 80 bucks an hour - so you're looking at $160 for 30, $320 for 100, plus material.

[smokediver576]

So, as being one of the newbies on here, especially when it comes to lathe work I have a couple of questions about how you would go about making this part.

(1) I'm assuming we are missing several dimensions such as the radius's on corners.
(2) The ID dimension and depth of the hole up to the threads (wouldn't this need to be larger than the threads?).
(3) Depth of the end between Z- and the bottom of the threads.
(4) +/- tolerances for all dimensions.

Just trying to learn. Thanks for allowing me to thread jack this a little.

Awall

[flick]

smokediver

1. Yes there should be a corner radius dimension
2. Thread depth is given (.5" depth)
3. Overall length is given as 1.5, so giving the depth of the hole beyond the threads would actually be bad practice. It's best if there's only 1 way to arrive at any given dimension, otherwise you can get conflicting tolerances that are very difficult or impossible to satisfy.
4. Yes, but any unstated tolerances would be covered in the title block of a proper drawing, which often states that 3 decimal place inch dimensions are +-.005, 2 decimal places are +-.01, etc.

I think the corner radius is the only actually missing dimension - the unthreaded portion of the hole is clearly meant to be the same as the minor diameter of the thread, and everything else can be calculated from the information that's there.

[smokediver576]

smokediver

1. Yes there should be a corner radius dimension
2. Thread depth is given (.5" depth)
3. Overall length is given as 1.5, so giving the depth of the hole beyond the threads would actually be bad practice. It's best if there's only 1 way to arrive at any given dimension, otherwise you can get conflicting tolerances that are very difficult or impossible to satisfy.
4. Yes, but any unstated tolerances would be covered in the title block of a proper drawing, which often states that 3 decimal place inch dimensions are +-.005, 2 decimal places are +-.01, etc.

I think the corner radius is the only actually missing dimension - the unthreaded portion of the hole is clearly meant to be the same as the minor diameter of the thread, and everything else can be calculated from the information that's there.

Man, this is what I love about this place. It's like a Masters degree in how to do things. I learn so much from you guys and can only hope to one day be able to help the next group of new folks. Thanks for the input Flick!

[MichaelHenry]

On a small turning center with a spindle bore to swallow that 1.5 inch material, that job is a 2 minute cycle time, tops. Around here you'd charge 1 hour for 30, 3 hours for 100, plus an hour to setup, plus material if the customer isn't supplying it. The ideal, small turning center to run that job would go for about 80 bucks an hour - so you're looking at $160 for 30, $320 for 100, plus material.

Would you make any adjustment for material, say 6061 vs 304SS? Do you make any allowance for tooling or maintenance or is that generally included in the hourly rate?

[GITERDUN]

Here's a video of a similar part in delrin- less the threading- probably not much more than 2 minutes per part if you set up some gang tooling.

[flick]

Would you make any adjustment for material, say 6061 vs 304SS? Do you make any allowance for tooling or maintenance or is that generally included in the hourly rate?

Definitely quote differently for different materials. I've had good luck quoting 314 at 2x the hours of 4140, and 4140 at 2x the rate for aluminum. Use different factors for all different materials - they don't have to be nice even numbers, but I base a lot of my estimates on those 3 materials as a guide. Al wouldn't be any different than Delrin - in fact the Delrin might be more expensive because it's abrasive to tooling and melts if you go too fast, even with coolant.

Might not make as much sense to use those factors on a job like this, because at small diameters your spindle would be maxed out regardless the material... unless maybe if you're dealing with high nickel alloys or titanium..

I include consumable tooling in hourly rates, so even if the spindle isn't turning any slower, you might increase the number of hours slightly for more difficult materials. 4140 shouldn't even dull an edge on a job like this if you're running your tools properly. 304 wouldn't be too bad either. 314 might take out 2 or 3 edges in a batch of 100. You're biggest time waster with a job like this would be if you were stuck drilling with HSS in difficult material. Making that hole would take longer than all the other operations combined, and you'd be sharpening drills while the machine runs instead of running 2 machines.

Quoting is very personal - combination of analysis, experience, and black magic. Really depends a lot on the equipment YOU have in YOUR shop and how badly you want the work.

[flick]

Here's a video of a similar part in delrin- less the threading- probably not much more than 2 minutes per part if you set up some gang tooling.

Yeah, I definitely offered 2 minutes as a very aggressive estimate for that part. If you actually want to make money without climbing in the pressure cooker probably have to go closer to 3 minutes ea. to give yourself time for material handling and QC. You could also give yourself a little more padding by charging for programming and then informing the customer that you can leave that charge off for repeat work, but it sounded like OP was more interested in getting the work than getting rich.

ETA: small jobs like this also go a lot faster on machines with rapids in the 1000 IPM range rather than the 100 IPM range, like that machine.

[MichaelHenry]

Quoting is very personal - combination of analysis, experience, and black magic. Really depends a lot on the equipment YOU have in YOUR shop and how badly you want the work.

Agreed, and thanks for the input. I struggle with quotes a bit trying to balance a desire for fair payment with a chance to learn while not screwing over customers that don't have much other choice. In the end I'm satisfied, if not happy, not to be losing money. I'm retired and do this part time out of my basement, though, so some days keeping busy is the main goal.

[flick]

Agreed, and thanks for the input. I struggle with quotes a bit trying to balance a desire for fair payment with a chance to learn while not screwing over customers that don't have much other choice. In the end I'm satisfied, if not happy, not to be losing money. I'm retired and do this part time out of my basement, though, so some days keeping busy is the main goal.

Sounds like you're living the dream! One day I hope to be machining as much to keep busy as to make money - a one man shop with nobody else to keep track of. Beautiful!