A Project Quest

[extropic]

It seems to me that building a spindle capable of precision grinding is a very high expectation of any amateur machinist. I wonder if there are any spindles commercially available, within an acceptable budget, that will meet the need? Alternatively, you might consider designing your Z axis to mount a conventional bench grinder to use as your motor/spindle. A good quality bench grinder would probably serve as well as a home built spindle. The Z axis motion could be a pivoting mount rather than linear travel.

If you insist on rolling-yer-own spindle, my vote would be for, at the wheel end, a duplex pair of angular contact back-to-back bearings, separated by as much length as the loads/package size/budget will allow and employing springs for preload/thermal compensation (as shown in the SKF link, Fig. 2, provided by John Hasler). Depending on the loads/package size/budget, I would use an additional radial bearing at the drive end of the arbor.

 

[Bill Gruby]

Seem that I have added some confusion here. "rwm" is correct in his statement on the preload being automatic. My bad here. I was referring to the preload that must be calculated for the rear bearing. It is not automatic as it is only a single bearing. My apologies gentleman. You guys are right on top of this. Kudos.

"Bill"

 

[JimDawson]

It seems to me that building a spindle capable of precision grinding is a very high expectation of any amateur machinist.

For an ''amateur machinist'' it might be, but we're not really talking amateurs here.

 

[Andre]

Spindles are not difficult to make for those who have experience working with metal and machine tools. Not overshooting a diameter, now that can get you!

It's surprising easy to turn a precision diameter, for say the spindle shaft. Turn to a thou oversize, then take a fine single cut pillar file and lightly dress the surface. Spindle should be turning at a medium speed (maybe 600 rpm) and make sure the par turns several rotations in the single stroke of a file. Measure with a micrometer occasionally to make sure the spindle isnt becoming oval in cross section or tapered. You can almost hold a tenth by filing and polishing. You can also polish after filing with oilstones for a flatter surface.

Sent from my XT1053 using Tapatalk

 

[Bill Gruby]

With all due respect an amateur machinist should have no problem building a spindle to precision. Expectations are the shortfall of the mind. The book --" Spindles" by Harprit Sandhu is the one to go to. There are no less than 9 precision spindles in it for the Amateur Machinist to build. It is Workshop Practice Series #27.

"Bill"

 

[extropic]

For an ''amateur machinist'' it might be, but we're not really talking amateurs here.

I must have assumed that the design/build was directed at facilitating hobbyist machinist's access to a home built surface grinder. A design appropriate for highly experienced/capable machinists is another matter.

 

[extropic]

Bill, Thanks for the reference to "Spindles". I'll take a look at it.

 

[ome]

I broke my right ankle a while back. Needed 4 pins the reset it. It is far from healed but mending OK. Will know more Tuesday.

"Billy G"

Sorry to hear that Bill, that can slow one down for sure, but sometimes not a bad thing.
Sending prayers for a total recovery
ome

 

[Mark_f]

First of all here , we need to clear up that ANYONE can build this grinder. Yes is is a large project, but if you look at each individual piece it is not so complicated. This is a project that can be built with the equipment most of us have. Being an amateur or professional does not really matter. Also, Building a precision spindle is not difficult in a home hobbyist setting. I have built several and they seem to work fine. It is just making close tolerance parts but if you go into thinking you can't do it ......then you can't. That is MY opinion.

Bill and I have discussed this very topic and respectfully disagree with any statements that the hobbyist machinist cannot build this project. The spindle is not that big a deal. anyone can build one if they simply pay attention to detail and follow the prints or instructions. Yes, it may require educating yourself a little if you have no experience at all, but if you can read you can certainly do this. This project WILL provide some education for many and hopefully inspire you to tackle some projects you may find intimidating at the moment. that is the purpose of inviting EVERYONE to participate in this build. TO EDUCATE and INSPIRE! We invite your questions, discussions, and suggestions, HOWEVER, we would like negativity to be avoided. Lets have fun with this and learn.


Mark F. & Bill G.

 

[ome]

Another topic for discussion is the seals on the spindle ends. Do you all think we should use rubber oil seals or a labyrinth seal? Rubber seals are much easier but put a drag on the spindle and create more heat, while the labyrinth seal is more difficult to machine but creates no drag or heat. Are there any other seal options? I have done both types and have a preference , but would like to hear ALL options and opinions.

For an ''amateur machinist'' it might be, but we're not really talking amateurs here.

I am an amateur, but please don't let that stop you, I will just have to catch up.