Lathe Carriage Rack

I recently acquired an old no-name (unable to locate any badges, serial numbers, etc.) lathe. It has a 12 inch swing (6 inches from
center of chuck) over the bed, and is approximately 33 inches from the face of the chuck to the tail stock. Used and slightly (understatement) abused, but serviceable and usable for my uses in a home shop. Power is derived from a 110 volt single phase motor and transferred by drive belts (like an auto's, not leather).
The major flaw at the moment is a damaged carriage rack. Several teeth are broken. The rack is 36 inches long, held in place by three counter-sunk socket head bolts. I probably need to count the teeth and can do that if anyone wants the info.
I know I will need to provide more information in order to narrow down my search, but for now I am looking for a source of either a good used or new rack..
Any suggestions/direction will be appreciated.
Thanks
Bob
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snipped-for-privacy@insightbb.com wrote:

Measurements! Need measurements!
No brand, no model, no measurements, no parts.
Measure the number of teeth per inch, or over ten inches. If equipped to do so, perhaps over ten teeth, accurately, from the same spot to the same spot on the tenth tooth down. accurate measurements of the width and height as well. If you have a digital caliper, check it in English and Metric units to see which looks most likely. If it is an American made machine it is like to be English pitch, if Asian, maybe English pitch, maybe Metric.
Rack is available from the likes of McMaster Carr or anyone listed under "gears" in the phone book.
A dirty substitute for a rack that I saw a picture of. Replace the gear that drives the rack, with a spool, made a similar diameter to the pitch diameter of the drive gear. anchor some 1/8 aircraft cable at one end, string it through the carriage, around the spool a couple or three turns, and out to the far side of the machine, where it is anchored with a turnbuckle to allow tensioning. Will allow the carriage to be cranked back and forth, though probably not all that accurate.
If a guy were hard up, he could probably make this work with the gear that is there.
Uglier things that have been done to bring a machine into service.
Rack is not too hard to get, once you know the size you need.
Cheers Trevor Jones
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wrote:

Or simply drill the busted teeth and put in proper diameter dowel pins.
Gunner
"I don't want to abolish government. I simply want to reduce it to the size where I can drag it into the bathroom and drown it in the bathtub. -- Grover Norquist
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I was going to say braze up the area and Dremel to profile. "Braze welding" is what the old books called it, was used for replacing teeth on very large gears at times. I'd want to clamp the thing down to some substantial backing material to help avoid warping, though.
Stan
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A REAL good point. I remember seeing blacksmiths make new steel teeth to fit into a cast iron gear and then braze them into a properly prepared cut-out. Should be easy to do with a flat rack that is probably mild steel. A person should be able to file out a couple of teeth in short order if no other idea presents itself.
Pete Stanaitis ---------------------------------
snipped-for-privacy@prolynx.com wrote:

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snipped-for-privacy@prolynx.com wrote:

Don't clamp something like this, it'll end up shrinking. Just heat it evenly, no problem.
John
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It would sure save a lot of time if you supply some pictures of the machine (to the dropbox or on your own page, so that others can identify it.
Pete Stanaitis ----------------------
snipped-for-privacy@insightbb.com wrote:

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Lotsa good advice so far.. . As has been said, get some pictures up somewhere and I bet SOMONE from this group can identify the lathe and people part out lathes on eBay all the time...
If you can't manufacture and brase in a repair(for what ever reason) If the busted teeth are in the same general area you could always cut the rack at the broken spot and do what ever is necesary to swap them end for end... essentially splice the good ends of the rack togther.. and yes this may require a bit of extra work on the ends too... you probably don't need to actually bond the pieces at the splice, maybe just drill a few new mounting holes in the rack and drill and tap the bed to match...
--.- Dave

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Unless you have something strange [or metric] more than likely the rack is a stock DP and PA. You can buy rack in standard DP/PA and cut to length/width.
see http://www.thomasnet.com/products/gears-cut-rack-34020206-1.html http://www.mooregear.com / http://www.macraesbluebook.com/search/product_company_list.cfm?Prod_Coder01950 http://bostongear.com/products/open/rack.html
metric http://www.qtcgears.com/KHK/index_Racks_files/khk144.htm
On Mon, 23 Apr 2007 17:05:31 -0700, "Dave August"

Unka' George ===============When we are planning for posterity, we ought to remember that virtue is not hereditary. Thomas Paine (1737-1809), Anglo-American political theorist, writer. Common Sense, ch. 4 (1776).
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On Sun, 22 Apr 2007 22:15:06 -0400, snipped-for-privacy@insightbb.com wrote:

Hey Bob,
You don't mention where along the rack that the teeth are missing. If they happen to be missing near the headstock, I'd try removing the rack and turning it end for end. If closer to the center, then cutting a piece the size of the missing teeth from the tailstock end and inserting that in place or doing a dowel trick as has already been mentioned.
I might also mention that older lathes are not selling as well as they did a few years ago, and can be had quite reasonably nowdays.
Brian Lawson, Bothwell, Ontario.
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On Tue, 24 Apr 2007 09:51:25 -0400, Brian Lawson

Thanks to all responding. Had already considered some of the suggestions (swapping end to end by turning over, that may be the easiest way). Also considered having a friend who is a welding instructor braze it. Also considering along with brazing, grinding down an old end mill to a point that matches the rack teeth and programming a cnc mill to cut the new ones to match.
Checked with Logan and the only thing they have close to the rack I have, is not correct. Someone mentioned McCallister. Their website does contain any rack info and they have not responded to my e-mail requests (in spite of their "One hour response," blurb).
And, this is one of those "older lathes," that are not selling well. But it sold well enough for me to end up with it. Items I am making are not rocket science projects and any slight tolerance differences won't be a major concern. (yet!)
Bob @ BobsShop -
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On Sun, 22 Apr 2007 22:15:06 -0400, snipped-for-privacy@insightbb.com wrote:
Attached (if it comes through) is a pic of the no-name lathe. Motor (110 v) is mounted behind the gear box. Connected to the gears by a rubber belt. The motor is mounted on a hinged support so it can be raised to provide belt slack. Two different drive choices coming from the motor (large and small pulleys) Three different ratios on the drive shaft for a total of six choices. As mentioned before - 12 inch swing over bed, from chuck to beginning of talistock I approx. 33 inches. Rack is 36 inches long. Three counter sunk socket head bolts and three spring pins support and align the rack. There is a small tool table inset on top of the gear cabinet. Sort of useless since the top must be lifted in order to change the drive belt pulley selections.
Continued to look for a hidden name, serial number, etc. but no luck
Bob
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BobsShop wrote:

Don't bother attaching pictures to usenet posts. Many of the news servers strip them automatically, and they don't get seen by the guys.
Go to www.metalworking.com and check out the How to Use the Dropbox link.
From what I saw in a McMaster cat today, you could well get a 3 foot section of rack from them for under $100. You gotta have the sizes worked out though.
Don't get hung up on where the holes are drilled. You NEED to know the tooth pitch and pressure angle, and have some idea of the others, so you know where to add shims or cu t down the stock part if required.
Cheers Trevor Jones
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wrote:

Trevor, thanks for the info. I had looked at McMaster before but could not find the rack. I was searching under lathe rack and got no hits. Did a new search on rack alone and there they were! I should be able to work out what I need with the info they provide.
Thanks again for the direction.
Bob @ BobsShop
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On Wed, 25 Apr 2007 22:21:06 -0400, BobsShop wrote:

Hey Bob,
Your local bearing house, selling products from companies like Boston Gear, should have or have access to rack gearing in many lengths.
Brian Lawson, Bothwell, Ontario.
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