I've got a Duplex D27 toolpost grinder. The surface finish from it is far f= rom perfect - I suspect that the bearings need replacement. The manufacturers, as is their habit, suggest sending the spindle back for = rebuild/exchange. I'm naturally sceptical of this practice being a tight gi= t at heart. Has anyone replaced the bearings on one of these? Should be qui= te simple in my book or am I going to struggle with balance problems for ev= er more?
Thanks
Charles
Often surface finish problems on a tool post grinder are caused by too hard a wheel being employed. White Aloxite in the softer grades is my favourite. Remember - "the harder the steel the softer the wheel" Any mounting play and as you say bearing issues will cause bounce and hence poor finish.
AWEM
Thanks
Charles
We tighten our slides right up when using said type of grinder, any play there will result in poor size and finish. Bob
Shouldn`t have problems with balance if you`re careful.Assuming they are precision matched bearings there should be dot`s on them to line up to get rid of any eccentricity.Doubtful if there`s anything fancy in there anyway,but if there is the price will give you a fright. As Bob says I`d be more inclined to make sure all the machine slides are tightened up and that the wheel is dressed and balanced before blaming the bearings. I`ve worked with a few of these over the years and never really rated them.A throwback to a bygone age when plus minus 0.005" was average for a lathe.
*THAT* depends on the operator - my old motorised Cincinnati ex-treadle lathe, which was worn in all the usual places would work down to a good tenth of your quoted figure - if you knew how.
(Mind you, if you didn't, you could obtain a spectacularly scalloped finish to your job.)
In the days before cad jockeys with no engineering experience,tolerances were thought about and understood. Therefore unless it was a bearing fit or some otherwise tight size companies did not waste time trying to catch tolerances that were not needed as it only increases cost. If it was volume precision work the lathe still turned to a plus tolerance and the work was ground. I did not say that in days gone by they could not turn to accurate sizes as your post seems to imply,rather that they did not waste their time doing it if it was unneeded.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.