Needs Pictures: 0
Results 1 to 5 of 5
-
14th Mar 2018, 09:26 AM #1Diamond Member
- Join Date
- Feb 2013
- Location
- Laidley, SE Qld
- Posts
- 1,038
Drill guide plates for drilling out sheared bolts and studs
I needed to remove/drill out 20 sheared off bolts and studs from tapped holes in an old engine (1935 Hudson 8), they were a mixture of 5/16" UNC and 3/8" UNC.
The eternal problems with this sort of work are
a)precisely finding the bolt centre
b)getting the drill to start on centre - bolts and studs never break off nice and smooth
c)keeping the drill on centre
Drill guide plates solved all of the above problems, I was fortunate on this job that the bolt layouts were measurable and I did have some clean holes that I could bolt the guides to. Using the mill and DRO I made few drilling plates, all from 12mm flat steel, to suit the different configurations of holes that were available for fixing and holes I needed to tackle.
Each drill plate had 2 sets of fixing and drilling holes. The first set of holes positioned a 6mm hole through which I firstly put a 6mm spotting drill 2 or 3mm into the offending bolt or stud, then I swapped over to a 6mm jobbing drill and drilled right through. After that the second set of holes positioned either a 6.35mm drill for the 5/16" threads or a 7.8 mm drill for the 3/8" threads and drilled right through. Those drill sizes are larger than the minor bolt/stud diameter and smaller than the hole tapping size. It goes without saying that you only use fresh sharp drills.
IMG_1215.jpg
After that its a matter of teasing the remnant of thread out of the block. Final score Bob 20, bolts and studs 0.
IMG_1227.jpg
-
14th Mar 2018, 08:27 PM #2
Hi Bob
I have a real soft spot for those big straight 8, motors Bob. My uncle had a Buick straight 8.
I thought it was one tough car.The kids could stand on the roof and watch the football from outside over the tin fence at the Brisbane, West End - Davies park footy ground in early 60's.
I can still remember the comment the uncle made."the b------d could pull a caravan up a cliff face in top gear"
It had big wheels, much bigger say, than a Holden of that time. Needless to say, it impressed me greatly as a ten-year-old of that time.
That drill guide plate is a wonderful idea.
The best of luck with your restoration.
Grahame
-
14th Mar 2018, 09:45 PM #3
That's a neat fix. I have exactly the same problem, the water jacket cover on my 1930's Morris 6 side valve engine, the 6mm bolts sheared off . So are you using a hand drill ?
-
14th Mar 2018, 10:13 PM #4Most Valued Member
- Join Date
- May 2011
- Location
- Murray Bridge S Aust.
- Age
- 71
- Posts
- 5,942
Hi morrisman, it was done on a DP, using a hospital bed???
You can read about it here, //metalworkforums.com/f65/t1405...gloat/page-142 thread number 2127
Hope this helps a bit.
KrynTo grow old is mandatory, growing up is optional.
-
15th Mar 2018, 12:27 AM #5Diamond Member
- Join Date
- Feb 2013
- Location
- Laidley, SE Qld
- Posts
- 1,038
This is my rotted water jacket which needed to be replaced, I guess its a similar set up to your Morris engine, this one is held on by 26 off 5/16" UNC bolts tapped through into the coolant, Despite my best efforts, a combination of gentle persuasion heat and violence only 9 off the little buggers unscrewed.
I did all the drilling with a drill press, it could have also been a job for a mag drill. Using a hand drill would have worked, very tedious though and a much higher chance of breaking a drill bit.
IMG_0035_22.jpg
Similar Threads
-
Pedestal Drill - buying guide for used equipment
By Commander_Keen in forum METALWORK GENERALReplies: 18Last Post: 6th Nov 2019, 07:12 PM -
Removing sheared bolts
By KBs PensNmore in forum METALWORK GENERALReplies: 5Last Post: 3rd Dec 2018, 08:47 PM -
Best way to remove these sheared bolts
By eskills in forum METALWORK GENERALReplies: 17Last Post: 24th Jun 2016, 11:08 PM -
Drilling Hard Bolts
By electrosteam in forum METALWORK GENERALReplies: 9Last Post: 3rd Jan 2012, 09:19 PM -
drill and tap guide?
By John H in forum METALWORK GENERALReplies: 20Last Post: 5th Sep 2009, 09:37 AM