Need some recommendations for tooling

[Chak]

Originally Posted by Lireal

I don't have any experience with it myself, but you might want to consider rotary broaching with your mill. With a quick search I found this:
http://www.polygonsolutions.com/rota...h-tool-holder/
http://www.polygonsolutions.com/rota...rotary-broach/

With those prices, it would make more sense to just buy a larger arbor press.

Nevertheless, I would still like an answer to this question:

Originally Posted by sanddrag

Has anyone successfully used a rotary broach on a round column mill? They just are not very rigid, even for milling.

[snoman]

I am getting in a little late but.. for any serious new manufacturing equipment 4k is very little to work with. If you decide on a lathe try and get one with a DRO. ( we had students standing in line to use our lathe this year). It is a sharp. Fixing up the little milling machine may be good. Figure out what taper it has and get a set of collets, get a keyless chuck, some endmills 2 flute HSS is good for alu. We use our Milwaukee portable band saw all the time. Do you have a good tap and die set. A small sheet metal shear is nice. Maybe a plasma cutter (requires a good air compressor ) personally I wouldn't get a cheep CNC . In that market you get what you pay for.

[mman1506]

Originally Posted by snoman

Maybe a plasma cutter (requires a good air compressor )

In terms of FRC use, what could you do with a plasma cutter that you couldn't do with a vertical bandsaw?

[Lireal]

Originally Posted by Chak

With those prices, it would make more sense to just buy a larger arbor.

Like I said, it was just a quick search. Here is a cheaper option for the holder: http://www.polygonsolutions.com/rota...FcNlfgodmAsOmg

[Lireal]

Originally Posted by mman1506

In terms of FRC use, what could you do with a plasma cutter that you couldn't do with a vertical bandsaw?

Generally, it can cut larger peices, like belly pans, and is able to cut complex shapes in the interior of material. A plasma cutter would be significantly more efficient in machining gussets to a decent accuracy in large quantities than a bandsaw and drill press.

[z_beeblebrox]

Originally Posted by Lireal

Generally, it can cut larger peices, like belly pans, and is able to cut complex shapes in the interior of material. A plasma cutter would be significantly more efficient in machining gussets to a decent accuracy in large quantities than a bandsaw and drill press.

Are you referring to a CNC or manual plasma cutter?

[Chris is me]

Originally Posted by Sperkowsky

As much as I would like to do this it probably won't make our school very happy as we already told them we were going to buy tools. It is our money and in all technicality we can do what we want but we have a very good relationship with our school and do not want to hinder it. (They have given us $7,000 this year alone on top of the $7,500 they always give us).

We do realize they are budget tools but right now its probably all we can afford/will be able to afford for a little while. We also have no machining mentors currently and the way I see it id rather start off with a cheaper tool.

Although, I totally see your point.

I think you're rationalizing a purchase you've already decided you want, rather than thinking this through fully. Why would your school be more happy rushing several different purchase orders through multiple vendors in about 10 days time, vendors they might not have a prior relationship with, rather than a single check to an organization they pay every single year already? Think about it. You can just use next years' registration money on tooling, with time to research it or potentially the ability to buy better quality used tooling.

[Monochron]

Originally Posted by Chris is me

The lathe is going to be much, much more important than the CNC router. I would prioritize even a crummy Harbor Freight benchtop lathe over a hastily bought router. You can buy all sorts of gussets these days, but making custom shafts, spacers, and all sorts of things is more necessary. I'd put that over anything else on this list.

I would guess this is more dependent on your teams design habits than anything else. For instance, we always design to use COTS shafts and spacers (or shaft collars), but often find the need for machined tubing or plate aluminum for gearboxes and the like.

It seems to me like having the freedom to design a gearbox or sheet metal that requires machining saves a lot more time than having the freedom to use custom shafts/spacers but having to fit your geometric design to COTS parts. Machine geometry is the big time sink for us, and a CNC mill/router would alleviate that a lot more than a lathe. Would you agree?

[Sperkowsky]

Originally Posted by Monochron

I would guess this is more dependent on your teams design habits than anything else. For instance, we always design to use COTS shafts and spacers (or shaft collars), but often find the need for machined tubing or plate aluminum for gearboxes and the like.

It seems to me like having the freedom to design a gearbox or sheet metal that requires machining saves a lot more time than having the freedom to use custom shafts/spacers , but having to fit your geometric design to COTS parts. Machine geometry is the big time sink for us, and a CNC mill/router would alleviate that a lot more than a lathe. Would you agree?

That's how I feel. I have never felt the need to make a custom spacer and really I see no advantage over cots offerings. But, being able to precisely make something like a drive train rail is going to be amazing.

[Steven Smith]

We have a CNC router, and we love it. It is quite a bit more rigid than a ShapeOko, but not nearly as rigid as some of the "built specifically for aluminum machines" some teams have. Just understand there is a learning curve as you get to know your machine and what tolerances it has.

For example, if you want to do a drive rail, you need a way to mount it to the bed to mill. You need to do this perfectly square to the direction of travel, or your holes (lets say, bearing) will be shifted to one side of the rail or the other. You either need a bit that can reach all the way through the tube to mill both sides (many don't reach, you need to run small diameter bits at router speeds, but the deflection on a 3/16" bit with 1.25" of stickout starts adding up). If you flip the rail, you need a way to maintain your index, and your error can get flipped as well, so if you were 0.010" high on one bearing, you could be low on the other, leading to a non-perpendicular shaft. IMO this is worse than having one that is a few thousands off in the X/Y direction on a rail, but milled through square on a manual machine.

Long story short (and that is just one of MANY personal experiences with a router), it is an amazing tool, especially if you have a fingerbrake, but it isn't magic. Don't expect to hold gearbox/bearing tolerances out of the box with little experience... but I still recommend getting one eventually. Many people recommend CNC plasma, which does have some advantages, but I'd argue the disadvantages over a router stack up for an FRC team. If nothing else, the ability to do polycarbonate (which is underutilized by many teams).

I struggled with wrapping my head around "why lathe" too... However, I spend more time on my lathe than my mill. Even in a gearbox, you focus on the plates, but having standoffs between the plates, stepped shafts to hold the gears, yada yada... all really nice to have. For basic lathe work of center drilling ends of shafts, turning down 1/2" hex, etc, a cheap $500 HF lathe isn't a bad place to start.

Rotary broaching is interesting, but I think you'd be happier with an arbor press and push broach. You need an arbor press anyway to press in bearings if you don't have one already.

[Michael Corsetto]

I recommended buy the lathe.

In parallel, reach out to local machine shops and find a sponsor to make your rails/plates/whatever other fancy, mostly flat custom parts you think you need.

The sponsor will be able to make your custom flat parts better than you will (maybe even faster!), and it doesn't cost any money to pick up the phone book and start calling local shops!

-Mike

[Sperkowsky]

Originally Posted by Michael Corsetto

I recommended buy the lathe.

In parallel, reach out to local machine shops and find a sponsor to make your rails/plates/whatever other fancy, mostly flat custom parts you think you need.

The sponsor will be able to make your custom flat parts better than you will (maybe even faster!), and it doesn't cost any money to pick up the phone book and start calling local shops!

-Mike

We have a waterjet sponsor with a very nice machine. He had made a few really high tolerance Parts. But, he doesn't seem to be too happy to do work for us and we are just not that comfortable asking him to cut stuff for us.

In the end we are buying the nicer lathe and the nicer router but forgetting breaching for the most part.

This lathe better be useful

[Monochron]

Originally Posted by Michael Corsetto

I recommended buy the lathe.

In parallel, reach out to local machine shops and find a sponsor to make your rails/plates/whatever other fancy, mostly flat custom parts you think you need.

The sponsor will be able to make your custom flat parts better than you will (maybe even faster!), and it doesn't cost any money to pick up the phone book and start calling local shops!

-Mike

I could see a lathe being more useful if you have found a sponsor for milling with fast turn around times. Not sure how fast Sperkowsky's team gets part, but for us was a ~3 week turn around time for 6 plates this past season. At that kind of speed, parallelizing by CNCing additional parts ourselves could create a distinct advantage for us.

[Steven Smith]

Originally Posted by Sperkowsky

This lathe better be useful

One thing I'd love to see, keep telling myself I'll make time to do, and never find it high enough on my priority list... is to make some videos showing "how we work". Specifically, what tools we use for what jobs in the shop, and what problems you can solve with those tools.

Some of those (<10% as a wild guess) require an engineer's level of knowledge to explain, but 90%+ of it is just "good shop practice" by good teams.

As far of what you are doing with F4, perhaps you could do a segment where students explain how their teams use tools. Both from the "top end teams" with high levels of machining resources, to explain what problems you can solve with the right tool, as well as mid tier teams that might have clever work-arounds to get good results out of cheaper tools.

As a start, you could use it as a way to get people to help explain the many uses of a lathe in FRC

[Sperkowsky]

Originally Posted by Steven Smith

One thing I'd love to see, keep telling myself I'll make time to do, and never find it high enough on my priority list... is to make some videos showing "how we work". Specifically, what tools we use for what jobs in the shop, and what problems you can solve with those tools.

Some of those (<10% as a wild guess) require an engineer's level of knowledge to explain, but 90%+ of it is just "good shop practice" by good teams.

As far of what you are doing with F4, perhaps you could do a segment where students explain how their teams use tools. Both from the "top end teams" with high levels of machining resources, to explain what problems you can solve with the right tool, as well as mid tier teams that might have clever work-arounds to get good results out of cheaper tools.

As a start, you could use it as a way to get people to help explain the many uses of a lathe in FRC

We actually have an episode like that scheduled on July 3rd. We are going to have someone from 5202, 4159, and 997. So a good mix of people.

A bunch of people on the chat were also yelling at me to get the lathe.