Is This Possible On A Mill?

[Izzy]

Alright guys so I've got a part i need to make but up until recently I haven't had any sort of machinery so ive been paying people to make parts for me... Well now ive got a Bridgeport and was wondering if it where possible to make this part on the ole mill? I understand it would be a million times easier on a lathe but I don't have one I don't think it's possible but I figured I would give it go and farm out the question. Demnsions are as follows...
44mm I.d.
55mm o.d.
300mm of m55x2.0 external threads
15mm of m48x1.5 internal threads,
A snap ring Grove
Wrench slots
The part is 335mm in length

 

[JimDawson]

Possible? Yes. Practical, I don't think so. It is possible to use a rotary table and gear it to the X feed to cut the external threads, or a 4 axis CNC mill would do it. Given the cost of tooling up to do this, you would be better to buy a lathe.

 

[Izzy]

Yea I figures it would be difficult if at all possible, here's the thing I just bought the machine not to long ago and i want to get tooled up anyways, I wana get some boring bars, reamers, fly cutters etc... What all would I need to do this? And how i go about the setup?

 

[Izzy]

the travel on my machine is:
X- 30"
Y- 16"
Z- 15"

 

[JimDawson]

The basic setup to cut the external threads on a manual mill would look something like this:



This is showing cutting a worm gear, but the principal is the same. Threading is just a spiral around a cylinder with a specific profile.

To make that part you would need a boring head and bars to bore for the internal thread, then a tap to cut the threads. It's possible to mill the threads with a thread mill, but you would have to gear the Z axis to a rotary table or spacer similar to the setup above.

Here is my super spacer


The snap ring groove could be milled with a tiny end mill or a slitting saw. The OD could be ''turned'' using setup similar to the above, but I have never been satisfied with the result when trying that.

 

[Wreck™Wreck]

Possible? Yes. Practical, I don't think so. It is possible to use a rotary table and gear it to the X feed to cut the external threads, or a 4 axis CNC mill would do it. Given the cost of tooling up to do this, you would be better to buy a lathe.

Just about anything is possible given time and money, that would be a formidable part using an old manual Bridgeport knee mill, one will have built a machine to make one part very slowly at great expense.

 

[Izzy]

thats pretty neat, so it looks like a dividing head with gearing to one of the X-axis hand wheels if im correct? also it looks like thats how you would go about cutting a helical gear for say a ring gear of a differential? if thats the case ive already been looking into dividing heads ill need them for other projects like cutting gears and custom sized hubs for my racecar anyways and ive always been the type of person to make due with what i have! dont get me wrong i understand a lathe would be much easier but the fact is i dont have one and i plan on buying alot of these tools for my mill anyways. does the gearing fixture have a name?

 

[TOOLMASTER]

I would stick to having someone else do it...

 

[JimDawson]

so it looks like a dividing head with gearing to one of the X-axis hand wheels if im correct?

That is correct. It is possible to cut any kind of gearing you want on a mill, but I have no experience with it.

does the gearing fixture have a name?

I'm sure it does, but I don't know what it is. ''Gear train'' maybe? It really hasn't been done this way in many years, at least not in any kind of production setting. It would be possible to design and build your own gear train components, including the gears. Theoretically it could all be done on a mill. It would be quite a job and take some time, but it could be done. I have a 4 axis CNC mill, but it's not a job I would tackle, just not cost effective. Spur gears can be bought for reasonable prices.

 

[Izzy]

the only kind of machine i have access too is the mill and im by no means a production shop ive been building this car for over 3 years so how long it will take to produce this is not a factor. anything i can learn and do myself i would much much rather do it like that than simply pay someone else to do it. theres just something about having my own personal knowledge on how to do things appeals to me. not to mention not everyone is made of money i make very little, i paid more for one of these tubes than i did for my entire machine with tooling! i have a nak for finding things ridiculously cheap, i just need to know what to look for. as for the gears you think my best bet would be to get a dividing head and buy my own gears and make my own fixture for it? is there somewhere id be bale to get more info on that process? trust me i would much rather do this on a lathe but i dont have that kinda money right now....