Wheel Spacers Questions #2

faavs730222

Registered
Registered
Joined
Aug 31, 2014
Messages
50
Hi, a while ago I posted questions about wheel spacers I want to turn. I got very nice info.

I made the mistake to make the ID 25mm, now I must turn it out to about 120mm. The OD is about 240mm, but it is cut very rough with a cutting torch. I chucked it in my 4 Jaw and are busy turning the ID to size. For the OD you suggested a RPM of about 38 RPM. For the ID, I am currently running at about 380 RPM. I cannot go much faster than that because the "disc" is not cut very even, and I get vibration. When the ID is to size i will clap it in the 3 Jaw and start on the OD. The problem is it is going VERY Slowly, I am taking about 0.8mm cuts at a time. the Feed rate is about .13mm/rev. I am using a Brazed Tip Boring Bar. I am at about 74mm on the first disc, and it is taking forever. If I use a Index-able Carbide tip Boring Bar at about 380 rpm, what cuts should I be able to take without braking my tips. On the Brazed tip Boring Bar I have quite a bit of Chatter.
Sorry for the metric dimensions.
 
I was wondering if you got around to boring these parts from the previous thread, the way that you are going about it will take roughly the rest of your life to finish.

Buy a trigon roughing tool, WNMG I believe, take a 5MM cut per side if your machine has the power, flood coolant is essential here.

I routinely rough 304 SS parts at 4MM DOC's, on a 30 HP machine however, this may not work at home.
Good Luck

I often make these plain steel parts, 300 M X 250 X 127 MM with a 127MM bore +.12 MM - .000 MM, I rough the bore with a 3" twist drill (This is a sight to behold)
I do them in a lathe to hold the bore tolerance of .005", the mill clamps on the chuck are counterweights, this is a well unbalanced setup.

We have a 2040 Fadal 3 axis mill as well, it will not interpolate a hole 5" deep at all.

rectanglein4jaw_zpsur9pqaz0.jpg
 
I would start with a 100 mm hole saw. Then finish bore.

If you have enough power, a deeper cut might be worth a try, maybe about 2-3 mm
 
We used a hole saw to do same but be sure to not over load the part holding the saw.

Another possibility is to make an "end cutting boring bar cut off" tool.

Locate a chunk of tool steel that can be placed in a holder that can then plunge into the work.

Sharpen the end to cut and the sides to clear.

Mark your "safe place" meaning a ring smaller than your finish area then cut inside that area.

We did this with our aluminum disks used for a tool we are making.

The hole saw worked fine for a smaller cutout but it unseated a MT5 size insert so would not suggest it to others unless very carefull.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
Hi I took the discs back to the engineering shop. They cut the ID to 100mm. I am now busy with the OD. I fixed the disc in the 3 jaw chuck. I am running above 38rpm, because i am using a carbide tool. Because the OD was cut very rough, the workpiece have a hammer effect on the crossslide an tool. I am not sure how to approach the work. The OD differ up to 5mm at places and the biggest cut I can take is about 1mm.4cfdcbe26717aff0105619a36ff8fed4.jpg The rough disc.eea2287cb14c1936689c341258cceb79.jpgThe OD and ID finished. 1dfa60759d2329a812e540368ed30106.jpgThe Carbide Tool I am using.


Sent from my iPhone using Tapatalk

4cfdcbe26717aff0105619a36ff8fed4.jpg

eea2287cb14c1936689c341258cceb79.jpg

1dfa60759d2329a812e540368ed30106.jpg

4cfdcbe26717aff0105619a36ff8fed4.jpg

eea2287cb14c1936689c341258cceb79.jpg

1dfa60759d2329a812e540368ed30106.jpg
 
Another possibility is to make an "end cutting boring bar cut off" tool.

Locate a chunk of tool steel that can be placed in a holder that can then plunge into the work.

Sharpen the end to cut and the sides to clear.


Sent from my SAMSUNG-SGH-I337Z using Tapatalk
A trepanning cutter, these often do not work well when the part is held in a lathe chuck, this sort of work is what a boring mill is designed for such as Bullard. The Company that I work for had a 48" table machine in the past, I wish that they still had it, I am now forced to do slow annoying work on a large engine lathe that the vertical would make short work of, the owner has said in the past, "sometimes I wish that we hadn't sold that machine".

As an example, 28" 304 rings done with a lathe, these took me close to 12 hours each, probably could have done all in 12 hours with the boring mill. On the lathe this required a chuck change to a 24" face plate, drilling, tapping and facing a part holding plate, milling clamps to hold the parts, clamping and indicating the parts, renoving the lathe bed gap, setting up tools that will span the gap , this is always a problem when the gap is removed ( I used a 2 1/2" diameter boring bar turned upside down running the spindle in reverse for the OD, you get the idea.

ringidturn_zpsiydwyfpv.jpg

Manchester makes excellent trepanning tools in large sizes. http://www.widia.com/content/dam/ke... Catalogs/Widia_Manchester_Th-G-C_English.pdf

ringidturn_zpsiydwyfpv.jpg

ringidturn_zpsiydwyfpv.jpg
 
Back
Top