# Atlas lathe bed width and rail thickness on the 10/12 power crossfeed model.



## agfrvf (Mar 13, 2017)

Looking into upgrading my 9-95A to a power crossfeed. I was wondering if I could fit the 10/12inch apron and slide onto my 9 inch machine. Also if anyone knows what the proper torque on the Babbitt bearing caps that would be helpful.

PS my ways are 5-3/4 x 3/8 inch

Thank you.


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## ghostdncr (Mar 13, 2017)

My 1936 (?) Craftsman 101.07830 12 x 24's ways measure 5-13/16 x 3/8" so I think the conversion MAY be possible. You'd probably have to reuse your compound as the 10-12" had a riser cast into the compound to bring the tool holder up into line with the higher spindle, as I understand it.

On babbet caps, I've not heard of a torque specification but that's certainly not to say there isn't one. I tighten them down until I start feeling resistance when turning the spindle by hand, then loosen them about a quarter turn and see how it runs. Several of these lathes I've had over the years would lock the spindle if the cap bolts were tightened to around 40 ft. lbs. or a little better. Using this method, I'll always mark the bolt heads with a silver Sharpie marker by running a single line from the top of the bolt down the side, over the washer(s) and just onto the cap surface. If any of the bolts move, it's immediately noticeable.


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## wa5cab (Mar 13, 2017)

After going through all of the available parts lists on the 9", 10", and early 12", I concluded that the four bed castings (four lengths) did not change from 1932 until 1957, when the heavier 1/2" bed was introduced.  The finish machining and part number suffix letters varied over the years mainly because several different leg designs were offered (with different attachment hole locations)   And where the two headstock positioning holes were drilled may have varied.  So I am relatively certain that the 10F carriage will physically fit onto your bed.

However, I suspect that the tool post will end up half an inch higher because I think that the difference in swing between the 9" and the first 10" was made up by raising the top of the dovetail on the assumed 10-9 carriage by half an inch above where the dovetail was on the 9-9 carriage that you have.  To check this, you need to lay a straight edge across the top of the compound slide and over the bed and measure the height.  Then, run your cross slide toward the back of the lathe to uncover the top of the dovetail.  Lay a straight edge across the dovetail and over the bed and measure the height.  Someone or several someones with a 10, a 10D and a 10F needs to make the same measurements.

On the babbit bearing cap bolt torque question, all that I have ever found on the subject is what's on the page from all 1937 copyright MOLO versions shown below.


end.

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## agfrvf (Mar 13, 2017)

3-13/32 bed to top of compound
2-15/32 bed to compound slide dovetail
1-3/32" bed to carriage dovetail

On a 9" lathe.


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## wa5cab (Mar 14, 2017)

OK.  Thanks.  I edited your earlier post to put the info all in one spot.  Now we just need the equivalent info for a 10, 10D and either 10F or 101.07403, 101.27430 or 101.27440.

BTW, where did you get "9-95A" as the model number of your lathe?  My available info says that the 9" model numbers were 918 (the stripped down Utility Lathe), and 936, 942, 948 and 954.


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## agfrvf (Mar 14, 2017)

I got the number off of the back of the headstock it looks a lot like a 10 but the bed to center measures 4.5. The headstock ooks unique. The headstock has no front belt guard.


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## wa5cab (Mar 16, 2017)

Hmmm.  The headstock casting and part number is 9-2.  I don't know what that number could be.


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## agfrvf (Mar 16, 2017)

It seems like a 918B looking at the lathe.co.uk site
It has the round style cover, banjo and gear instructions, swiveling compound, no back gear, and 2 pulleys for the motor.


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## wa5cab (Mar 17, 2017)

Where did you find a photo of *agfrvf'*s lathe?  In any case, the 918's also have a 9-2 headstock casting.  And if by "cover"* *you mean the change gear cover, that's a date or age thing.  Prior to about 1936, all seem to have had the fabricated cover.  After that, they were cast.


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## agfrvf (Mar 17, 2017)

http://www.lathes.co.uk/atlas/page2.html
I had to read the paragraph carefully the model info together.


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## wa5cab (Mar 17, 2017)

AG,

Disregard my "photo" question.

If it has a 2-step motor pulley and a 3-step spindle pulley, then it's one of the 918's.  If it has a swiveling compound and all of the change gears, it is a 918B.  There is a parts list for the 918's in DOWNLOADS.


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## wa5cab (Mar 17, 2017)

Group,

I know that there have been a dozen or more recent mentions of 10" machines in this Forum.  It shouldn't take any of you more than an hour to take the two height measurements requested above and report them here.  So please respond.


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## westerner (Jun 6, 2017)

Dang- I was headed to the shop to get some numbers, then I remembered- I have cleaned and repaired my apron/carriage assembly, but they aint back on the lathe! Gimme a minute.....


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## westerner (Jun 26, 2017)

westerner said:


> Dang- I was headed to the shop to get some numbers, then I remembered- I have cleaned and repaired my apron/carriage assembly, but they aint back on the lathe! Gimme a minute.....


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## westerner (Jun 26, 2017)

Oops- fat fingers! Anyway, on my 101.27440, I get 1.295 to top of carriage dovetail, and 4.821 to top of compound. This is a 12" lathe. Hope this helps.


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## wa5cab (Jun 26, 2017)

The original question (or one of them) was whether or not the power cross-feed carriage would fit on a 9" lathe.  We now know that the height of the carriage dovetail above the ways is 1.094" on the 9" and 1.295 on the last three 3/8" bed 12" (and by extension, the 10F, as it uses the same carriage).  We know that the basic carriage dovetail dimensions never changed from 1932 to 1981.  So your carriage slide, compound swivel and compound slide should fit.  Whether your compound slide will fit the the dovetail on the later compound swivel or not we don't know.  You will just have to try it if you make the conversion.

Don't forget that if you do this, you also have to change out your 5/8" lead screw for a 3/4" one.  I would suggest that it would be best to use parts off of a 10F than a 12", and I think that you will have to change out the lead screw right bearing.


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## agfrvf (Apr 12, 2018)

I now know the carraige of my TH-54 will fit my 918. However the lead screw is a different diameter but same thickness at the transmission.


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## wa5cab (Apr 13, 2018)

Right.  Way thickness varied, but way width and distance between the ways remained the same from 1932 through 1981.  As far as I've been able to determine, the same bed castings were used for everything except the 6" up until 1957 (hole locations varied).  And except for the leadscrews with the slip clutch on the left end, all of the 9", 10" and 12" lead screws were 5/8" diameter on the left end.


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## Headrc (Jul 27, 2018)

I am curious on this as well ... agfrvf ...have you actually done this modification?  I have an Atlas 9 inch that maybe in the future I might want power cross feed on...


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## agfrvf (Jul 27, 2018)

A TH-54 fell in my Lap and I sold off the 918. I believe it is possible to swap it. My guess is you would need the saddle & apron assemply, Lead screw and F/N/R transmission.


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## Headrc (Jul 27, 2018)

Excellent ...glad you acquired the TH-54.  And looking at it ...I may try a different approach if I pursue this.  Because of the issue of cost for the saddle and apron assembly.  But I will continue to look around as there is no immediate need.  Thanks for the response.


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## wa5cab (Jul 28, 2018)

The 10F carriage (which is also used on the 101.07403, 101.27430 and 101.27440) will fit the earlier beds.  And aside from some (hopefully) improvements to the gears inside, the 10F without QCGB used the same FWD-OFF-REV gear box as used on the earlier machines.


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