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G0755 Grizzley mill

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Vintage Indian Chief

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Aug 1, 2018
Messages
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#1
New to the forum all.
Retired and setting up a garage shop,bought a Griz gunsmith lathe and the G0755 mill.The lathe met my expectations and the mill for the price was OK.Problem
seems that the bottom bearing on the R-8 end is running hot on higher speeds.No help from Griz techs as to what hot is.Ive seen here some of you guys have the 755 and would be interested in getting your opinions.I have over 50 years experience working with opposed Timken bearings and preload or clearance is usually established with spacers.I removed the quill assy. and loosened the lock nut (dead tight)and loosened 1/4 turn.Reassembeled and no change in heat.10 minuets run time on hi 3 you cant hold your hand on R-8 end. F Y I I took a white rag with oil applied and wiped the spindle bore and the rag was black with cast iron particles.Kept at it until no discoloration noted. I read where to remove spindle from quill you have to press spindle out.Makes no sense that both upper and lower bearings are pressed on the spindle if the lock nut is used to set preload!!!!Any thoughts

Mike AKA Indian Chief
 

Vintage Indian Chief

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Aug 1, 2018
Messages
9
Likes
11
#2
New to the forum all.
Retired and setting up a garage shop,bought a Griz gunsmith lathe and the G0755 mill.The lathe met my expectations and the mill for the price was OK.Problem
seems that the bottom bearing on the R-8 end is running hot on higher speeds.No help from Griz techs as to what hot is.Ive seen here some of you guys have the 755 and would be interested in getting your opinions.I have over 50 years experience working with opposed Timken bearings and preload or clearance is usually established with spacers.I removed the quill assy. and loosened the lock nut (dead tight)and loosened 1/4 turn.Reassembeled and no change in heat.10 minuets run time on hi 3 you cant hold your hand on R-8 end. F Y I I took a white rag with oil applied and wiped the spindle bore and the rag was black with cast iron particles.Kept at it until no discoloration noted. I read where to remove spindle from quill you have to press spindle out.Makes no sense that both upper and lower bearings are pressed on the spindle if the lock nut is used to set preload!!!!Any thoughts

Mike AKA Indian Chief
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
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#3
New to the forum all.
Retired and setting up a garage shop,bought a Griz gunsmith lathe and the G0755 mill.The lathe met my expectations and the mill for the price was OK.Problem
seems that the bottom bearing on the R-8 end is running hot on higher speeds.No help from Griz techs as to what hot is.Ive seen here some of you guys have the 755 and would be interested in getting your opinions.I have over 50 years experience working with opposed Timken bearings and preload or clearance is usually established with spacers.I removed the quill assy. and loosened the lock nut (dead tight)and loosened 1/4 turn.Reassembeled and no change in heat.10 minuets run time on hi 3 you cant hold your hand on R-8 end. F Y I I took a white rag with oil applied and wiped the spindle bore and the rag was black with cast iron particles.Kept at it until no discoloration noted. I read where to remove spindle from quill you have to press spindle out.Makes no sense that both upper and lower bearings are pressed on the spindle if the lock nut is used to set preload!!!!Any thoughts

Mike AKA Indian Chief
I have a PM-932, which is similar to your mill. You are correct, it makes no sense to have the upper bearing a press fit onto the spindle. It should be a slip fit so you can adjust preload with the bearing retaining nut. It sounds like when you backed off the retaining nut the bearing didn't move on the spindle, therefore your preload didn't change and it continued to run hot. My PM-932 upper bearing was tight like yours. When I switched over to angular contact bearings I polished the upper bearing fit area for a slip fit. I now run as high as 8800 rpm and the bearings only get warm to the touch.
 

Vintage Indian Chief

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
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Aug 1, 2018
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#4
Thanks for the post.As suspected I will hone upper bearing for proper fit.Timken bearing types only run hot when not properly fitted or overloaded.Have built many assemblies before and no problems.Cheap or no attention to detail.
Thanks Mike
 
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