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Tapered roller bearing expert wanted

L.Svedberg

Plastic
Joined
Jan 16, 2021
Hello everyone!

I have a question regarding Timken TSF series single row tapered roller bearings. I need to replace the original Gamet spindle bearings in my old Harrison lathe and even if I was able to source the correct items they would be insanely costly. I've been looking at Timken Tsf series bearings,and there is no item 100% correct in dimensions, but if cone and cup were to be combined differntly I would have a match...

Ny questions is this: can the 742B cup be combined with the 755 cone?

Very grateful for any information 👍

Cheers/ Lasse
 
I'd say no. 742B / 745 bore range is 2.500 to 3.3475 with 5.909 cup OD

752B / 755 bore range is 2.875 to 3.5625 with 6.375 cup OD

Both of these are FLANGED CUP

Per early 80s Engineering Journal
 
I have a Timkin bearing spec book at work that lists all the cups and cones and combinations. Check and see if it is online. If I can remember I'll check.
 
There are plenty of listed Timken bearings that are not current production ( tier 1 ,I think they call them,)......anyhoo,the prices of these are astronomical ,and your Gamets will be cheaper ....so get prices before wasting time on combinations.
 
Doesnt necessarily have to be the 755 cone, but it needs to be a 3.00" ID cone that can be combined with the flanged 742b cup.
 
Maybe the 748S cone? It has as standard the non flanged 742 cup. Seems the flanged 742b cup would be a match if I understand the info correctly?
 
I always thought these Harrison, Clausing Colchester lathes were scrap if they needed a spindle bearing replacement.
I have a 1974 Clausing Colchester 15X50. I love it. I would hate to lose it, but aren't the gamet bearings >$3,500?
I had no idea you could use an alternate bearing set?
Please keep us posted.
 
I bought new "Gamet" spindle bearings for my Harrison "Alpha 1330 s" about a year back.
Shopped around and found a source that was half the cost of the same bearings from Harrison....

Literally half the cost of other suppliers.
Bearings came in original sealed containers
Bearings were not greased , needed to get the proper grease and apply when i installed the bearings.
I was able to obtain the Harrison run in and adjustment procedure for the bearings.

Source:
Quality Bearings Online - Deep Groove, Tapers, Precision

They are located in the UK, but shipping and delivery was not a problem.
Cheers Ross
 
The other point is stock Timkens will have around 1/2 thou semi random runout.....which will compound if both front and rear spindle are replaced ..........if by chance you get the $25 truck wheel bearing kit Timkens .....?
 
I'm not considering the cheapest series Timkens, but not the "000" super precision ones either. The ones I've seen can be had for around $250 each. Considering the value of the entire lathe, I cannot justify spending thousands of dollars on these spindle bearings.

So, 748S cone and 742B cup? A working conbination?
 
I'm not considering the cheapest series Timkens, but not the "000" super precision ones either. The ones I've seen can be had for around $250 each. Considering the value of the entire lathe, I cannot justify spending thousands of dollars on these spindle bearings.

So, 748S cone and 742B cup? A working conbination?

Is the value of the lathe the right thing to base repair/refurbish cost on? How about the quality of work you will do on it? If you are a fab/weld shop and just need to turn down pins and bushings you have a different need than a toolroom/prototype shop.
 
Ive replaced lots of spindle bearings with standard stock ones,as I used to buy and sell machine tools.....in general ,Ive never had a complaint from a buyer ,of a used machine,when the buyer was offered the option of new Gamets at much higher price. .....In my experience ,the lathe will have no issues other than that finish will be a lower standard than with perfect spindle bearings.....In most jobs other factors affect finish far more ,and youd need to be trying to get a mirror finish on free cutting bronze to notice a difference....as an example......The used machine will have bed wear ,alignment issues ,etc as well.
 
I'm not considering the cheapest series Timkens, but not the "000" super precision ones either. The ones I've seen can be had for around $250 each. Considering the value of the entire lathe, I cannot justify spending thousands of dollars on these spindle bearings.

Believe that the cost from the source i linked above was $ 380.00 per bearing,not thousands....Not a sizeable amount above your $250.00 ea for a "maybe" ....
Not sure on your model Harrison, but on the Alpha 330s as well as the Clausing Colchesters the rear bearing cone is built with an integral spring setup to preload the cones...
Something you won't get with a generic fit up....
Cheers Ross
 
Having looked into this quite thoroughly ,I know that searching out odd Timkens is a complete waste of time......if the bearings are not current stock ,you can forget it.......And in any case ,I never used Timkens ,but Koyos or some other Made in Japan bearing.....its likely Euro made SKF s would be as good ......if the cups are flanged ,then IMHO ,genuine/Gamet is your only simple choice......yes I have got around this by reboring the front bearing bore on lathes ,but its quite likely I wasnt able to equal makers standards............When you are selling machine tools ,the whole point is to sell the damn things,not pontificate endlessly about some feature you havent repaired......Information overload scares off buyers.
 
The lathe in question is a Harrison 190. The original Gamets are discontinued, and very very rare. Very odd imperial sizings, and the one quote I have been able to get was several thousand dollars per unit. Even Gamet themselves first claimed these never even existed, until I supplied photographic evidence... This lathe was bought by me knowing about several issues, including the spindle bearing problem, but I didn't expect the dimensions to be this odd... I am aiming for a functional machine to use, or if I not satisfied by its performance, I will sell it to someone who has use for it in its less than perfect condition. Only other option is to scrap the machine, but I reckon this one even with some tiny spindle runout would be far superior compared to the shit machines a lot of people are using.
 








 
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