What Price?

[David Powell]

I am in the process of acquiring a new customer. He needs lots( 400 or so in a batch) of parts. Most are round aluminium, varying lengths, have to be +/- one thou in length and be tapped centrally 6/32 by 5/8 " deep., Some one end some both. I am making a few samples now using a 13/37 lathe, tailstock mounted turret, stops and tapping head for the tapping. What both he and I would like to know is what would be a " fair " price. He will supply the material, I am responsible for all the rest. I am expected to deliver 100% usuable parts, so expect to have long sitting times inspecting. Do any of you do this kind of " mass" production and if so how do you do the pricing, and where do you draw the line on buying new/ extra equipment to make the job go like hell? regards David Powell.

[2ManyHobbies]

What is your time worth?
How long does it take you to make a part?
How many parts will you have to run to break even on new/faster tooling?
Do you mind being a slave to the finished part bucket for the duration?

If you have a turret, stops, and can feed the job through the head, you have nothing more than setup and rote muscle memory for an entire batch of parts. If you can manage and it would be enough repeat business, then rigging a go/no-go setup or three could speed the testing.

[MickeyD]

If you are going to try to do these on a manual setup someone with a cnc lathe will eat you alive on price. Now that being said, I run some similar parts from delrin and hold +- .001" in the cold saw (have to blow the stops between every cut) and then drill and tap them on the cnc mill, but they are only in batches of 40 or so. Do you have anyone with a cnc lathe you can sub these to?

[Elninio]

you're going to get RSI if you tap all those holes manually!

[macona]

+/- .001 in length??? In aluminum? At what temperature?

Do you at least have a DRO?

Unless I had a turret lathe or cnc I wouldnt touch them.

[Rustybolt]

plus or minus .001 on a length is very difficult to do on a manual machine, hell it isn't easy on an automatic one either.

I agree. DRO is almost manditory for this and instead of a cutof tool I'd look into a cutoff saw on the back slide.

[airsmith282]

i dont do mass production cause is cuts into the profit to much , and people excpect the cheaper price for mass production stuff, how ever , and idea would be call the local cnc shop and ask them what they would charge for the same job, and then knock off a few bucks so your cheaper this way you get the job and if the customer complains simiply do as i do , tell him go to a cnc shop where things can be mass produced and see what they are charging and let him know that upon his retun to you , you would like a coffee and donut lol ..

time is money and so is ware and tear on quipment and cost of hydro runing the tools and so on and so on from a business or hooby point of view, even i wont work for free, id rather lose a job then work for free,

[Rosco-P]

Who came up with the tolerance requirement, what's the application and why? It almost sounds like the customer just tossed out the +/- .001, since he has no idea what a fair price would be.

It sounds like he has you making P.C. board or electric component standoffs. Has he gotten it in his head that he can have them made to custom length, cheaper than he can buy standard length parts?

You have a turret for your tailstock, but not a turret tailstock (way more rigid), do you have a tapping head for it and a lever collet closer for your headstock? Without them, I think your cycle time will eat you alive.

For Q/C, you need to figure how many pieces per hundred to inspect. No way are you going to check every part.

[DR]

That's a surprisingly hard part to do in the quantities mentioned on your equipment.

The length tolerance is a major issue. If the stock material will fit through your lathe spindle you're looking at a parting operation, plus a facing operation on both ends to hold length tolerance.

6-32 tapped 5/8" deep is no picnic either. A form tap is the way I'd do that one. Use the max allowable size tap drill so you're making a low thread percentage.


But, before you get too far into this, make sure the specs he's given you are realistic for the application. In my experience anyone who would consider giving a job like this to someone with only your equipment most likely is not very knowledgeable in part design.

While it's nice to make some money off your equipment, sometimes it's best to stick with parts that can be efficiently done on your machines. This certainly is not one.

[DR]

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call the local cnc shop and ask them what they would charge for the same job,

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time is money .................................................. ..................................

That's an odd piece of advice.

You would actually suggest wasting the CNC shop's time with preparing a quote as if their time is not worth money?