drilling grade 8 bolts?

[The Cobbler]

anything I should know about drilling grade 8 bolts on a lathe?
I need to make some leveling bolts , 1" fine thread and all I can find is 1" grade 8 bolts. need to drill a 3/8" hole thru the center to set an anchor

Tks

 

[BuffettFan]

I did this recently to make some threaded sleeves.
Went easier than I anticipated.
I faced the markings off of the heads, center drilled, then drilled and reamed 1/2" through, bored a 5 degree taper and finally parted off and faced both ends square and to length.
Facing and drilling around 350 RPM and parting around 100 RPM.
HSS drill bits, 80 degree facing insert, small triangle boring insert.
I may have some pics.

 

[The Cobbler]

great to hear. thanks.

 

[JJohns3WG]

They don't machine to bad, grade 8 is a tensile strength not hardness.

 

[sberry]

Why fine?

 

[BuffettFan]

They were used as tie rod end adapters. Threaded into the steering knuckle.

View media item 80532
I made them for a member on another forum for a 72 Chevy p/u he's working on.

View media item 80533
Lowering the truck worsened the already bad bump steer. Relocating the tie rod ends seems to have helped correct the issue.

 

[The Cobbler]

Why fine?

if that's for me, it's cause the thread on the machine is fine already

 

[rsanter]

Sharp bit
Go slow
Use oil

I have done that before on the lathe to make adjustable feet with screw on rubber pad on the bottom

 

[BuffettFan]

if that's for me, it's cause the thread on the machine is fine already

There was another post that has since been deleted asking about the taper. I assumed it was referencing my original reply.

Have you had time to try drilling them yet? Sharp drill bits, low RPM and a slightly heavy feed will be your friends. Just don't let the drill bits rub themselves to death against the bolts. I drilled and tapped a pc of round stock and locked the bolt into it with a jam nut to chuck it up and not bung up the threads. Worked good.

 

[The Cobbler]

have not got around to it yet. probably next weeks project
thanks for the info.

 

[The Cobbler]

I have some jam nuts that I can put on the bolts to protect the threads , I'll run one up to the bolt head & set a second nut farther back to line up with the jaws

 

[matt_i]

If you have access to a collet system that's the best way to preserve concentricity and not impact the existing part.

If you have access to NM-B wire scraps, simply strip off the insulation and wind up a coil spring of copper around the thread. Now you can clamp on the part and not impact the thread crests. Should stay reasonably concentric.

My goto pilot bit is a 5/32" for machine work. 120 deg spot drill, then the 5/32" pilot, and then I'd step right to 3/8".

 

[The Cobbler]

I was searching google for something similarly related & this 5-3/4 yr old thread popped up.
Never did finish this project, I started & it sits . I faced off the bolt heads and never got around to drilling & tapping.
I need a list , not a honey do list, a cobbler do list

 

[Monza Harry]

I was searching google for something similarly related & this 5-3/4 yr old thread popped up.
Never did finish this project, I started & it sits . I faced off the bolt heads and never got around to drilling & tapping.
I need a list , not a honey do list, a cobbler do list

Keep that pace up @ "The Cobbler" and you will be as fast at these projects as I am! That is almost 6 years to bounce back, I'd bust on ya' but that isn't even as slow as my top 3 slowest projects! Harry