B&S 510 surface grinder not grinding parallel front to back.

[Gibson]

I recently bought a B&S 510 surface grinder and it is good shape for a 1950’s vintage. I have one issue. As I grind front to back I grind heavier at the front of the table than the back. I dusted the table and this did not help. I can’t find in my manual how to adjust this error.
Any information would be greatly appreciated.

Thank and keep making those chips!

Scott

 

[Ulma Doctor]

Affix a dti to the spindle or wherever you can to sweep the table
This will give direct readings to the deficiencies

It is doubtful that you will correct any faults by grinding, you may be creating trapezoidal features by doing so

 

[Gibson]

Thank you for your input Ulma. I will not dust the table again.

I did do a sweep with a .0001 dial indicator. I saw .0003 error in the axis front to back over 5 inches with the front being low. But when I grind I find that I am getting an .008 low reading in the front. I can hear and see the increased depth of grind as I come forward.
I am going to verify my indicator again. I am measuring my grinding test piece with two different Starrett .0001 micrometers. They correlate.
I am going see if table is traversing properly with multiple indicators. I will do this with out the grinder running.
I will update with my results.

Again much appreciated!!

Scott

 

[Alcap]

Just got my first surface grinder myself and very interested in learning everything I can . When you say you’re indicating the table do you mean the magnitic chuck or table itself? Could the magnetic chuck being on or off effect anything ?

 

[Dabbler]

There's a lot missing from your description. "when you grind" can vary a lot. Are you taking 1/10 of a thou, and the parallel piece drops off? or are you taking a massively deep cut? Have you done a 5 block test on the grinder?

Some of your error can be deflection or problems with your support system...

My B&S surface grinder uses rollers on the ways; Is yours rollers or oil floated dovetails? If dovetails and your oil pressure is low on the one side, it can make that much of a difference. On my buddy's British grinder, grinding with the pump on was about .014 higher than grinding with the pump off, but still oil on the ways. Sadly it was sold 2 years ago so I cannot do any more comparisons.

 

[Dabbler]

... after some research your 510 is very similar to my Valuemaster, except I have 4 more rollers on each side of the table.

Have you serviced your magnetic chuck? Is it possible it is coming apart? I'm looking for something that is not supporting vertical pressure the same from side to side....

Here's another diagnostic: using a plunge indicator (NOT a test indicator) set up to measure vertical deflection on the outside of the chuck away from the grinding surface. Grind a piece, say 1" by 5" set across the chuck. See if there is a difference in deflection During grinding as opposed to when the wheel is not in contact. This will provide essential data to help you fix the problem.

 

[Gibson]

There's a lot missing from your description. "when you grind" can vary a lot. Are you taking 1/10 of a thou, and the parallel piece drops off? or are you taking a massively deep cut? Have you done a 5 block test on the grinder?

Some of your error can be deflection or problems with your support system...

My B&S surface grinder uses rollers on the ways; Is yours rollers or oil floated dovetails? If dovetails and your oil pressure is low on the one side, it can make that much of a difference. On my buddy's British grinder, grinding with the pump on was about .014 higher than grinding with the pump off, but still oil on the ways. Sadly it was sold 2 years ago so I cannot do any more comparisons.

Mine is a roller system as well. I was taking .0004 cuts. I could hear the grinding get deeper as I move the table grinding from the back of the table forward. Side to side seems good.
No I have not done 5 block test. I will do that in the next few days.
Thank you for the advice…

 

[Gibson]

... after some research your 510 is very similar to my Valuemaster, except I have 4 more rollers on each side of the table.

Have you serviced your magnetic chuck? Is it possible it is coming apart? I'm looking for something that is not supporting vertical pressure the same from side to side....

Here's another diagnostic: using a plunge indicator (NOT a test indicator) set up to measure vertical deflection on the outside of the chuck away from the grinding surface. Grind a piece, say 1" by 5" set across the chuck. See if there is a difference in deflection During grinding as opposed to when the wheel is not in contact. This will provide essential data to help you fix the problem.

I have looked over my mag chuck and it is in good condition. I will run my plug indicator as you suggested as well as do a test grind. I bought a Lufkin precision level recently as I sold my Starrett years ago. I do need to level the grinder. I’m sure the will help a bit.
I have made sure everything on the machine is tight, I have checked for play on all the moving parts. The spindle is well within tolerance. But now that I am thinking about it I need to check the motor mount. I have a direct drive spindle.
I will update will my progress.
Thank for the feed back and suggestions.

 

[Gibson]

Just got my first surface grinder myself and very interested in learning everything I can . When you say you’re indicating the table do you mean the magnitic chuck or table itself? Could the magnetic chuck being on or off effect anything ?

I am indicating over the chuck. I have not checked it with it on.
will do that tonight.
Thanks for the input.

 

[Gibson]

Well the issue is solved as to the heavy grind at the most forward end of the Y direction.

The last .650 +/- .005” of the table lifts up .008”. Not sure if it is an over traveling and riding up on the lead of the thread on the screw or if there is something else causing it to lift the table up. I have attached an indicator on the table to read zero when I am .250” from where the lift starts. Grinding very good now.
Not sure if there is supposed to be a stop on the screw or a solid travel stop elsewhere.
If anyone has any information I would appreciate it. The table removal is next. But not anytime soon. Getting ready for Christmas!
I must thank everyone for your help and advice. I am much further along as you have all helped me to understand what issues can arise. Plus you made me think deeper than I was. Lol
Merry Christmas and Happy Holidays to you all.

Scott