I have this untouched sl1000 for sale. I'd like to get $550 for it. It comes with the upgraded motor, vertical attachment, headstock handle, tool holder and power feed. Mechanically it is in very nice shape, it only needs a new belt. It looks bad but its just old age grime, and a bit of surface rust that will polish off. I have not even wiped it with a cloth yet - in as found condition. :)

I bought it as a fixer upper, but I have too many projects (And Unimats! - I have another full cherry one available for $750 if anyone is interested). I'm refreshing a maximat 7 now, and thats been my labor of love for some time!?

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Ouch!

Back in about the year 2000 my dad gave me a complete Unimat DB200 he was given by a man who had purchased it new. The man had a terminal illness and knew my dad was a machinist and wanted it to go to someone who would appreciate it.
Some years later after my dad passed away I was cleaning out his shop and came upon several small boxes, each with individual threaded items in them. I had no idea what they were and tossed them into the trash. They were unused in original boxes.
I could still kick myself to this day.

Tim

Metric threads are 60 degrees, the 55degree masters are Whitworth.

Michael

On Wed, Mar 1, 2023 at 10:17 PM, vt_biketim wrote:

Were they hardened? More to the point, since the followers are brass, can you get away with not hard? And are they cut with a buttress thread form? I've never actually seen a threading attachment.

If the master is made of a decent steel, and the follower brass, they will be OK without hardening. The amount of force on them and the hours of use will be so little that they will be fine. The main thing is to get a decent smooth finish on the master.

All the pictures I've seen - including the one just posted clearly show a "normal" thread, probably 60°. Again the forces don't need anything heftier.

They look simple enough to be 3D printed. I dont think there is much force on them. I could be wrong.
I dont have the dimensions so i'M at a lose to make them. There must be an Sl owner who 3d prints try it.

?

A nice little gem from the past:


DW

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The glove box latch on my ‘65 Lotus Elan is 3/4 x 27

Hello Bill,
I just found my information on the Atlas 6” lathe and it also shows 27 TPI as standard.

I am know my 7x16 MicroMark minilathe can also be configured to cut 27 TPI. I have the mathematical formula to calculate the gear tooth requirements for any thread. Very handy to have.

Tim,
The Unimat thread masters I have had were not buttress thread form but “V” form. I would assume the metric thread masters are 55 degree thread form but I am not sure and the US version is most likely UNF 60 degree (unified national fine).
Perhaps someone here on this group can clarify this
.

I think uncommon TPI configuration(s) were done on purpose to keep the rookies (like me) from trying my own repairs.

This is an interesting thread though.... couldn't resist.

Speaking of rookies, this one generates for g-code, I don't have a CNC lathe.... (still.)
https://sct-usa.com/thread-mill-code-generator/

Tamra

Were they hardened? More to the point, since the followers are brass, can you get away with not hard? And are they cut with a buttress thread form? I've never actually seen a threading attachment.

Tim in VT

I just ran out back to look at my Clausing 4902. It has 27 tpi right on the QCGB. Also 22,23,24,26,28, then jumps to 32. No 25, no 30.?

OTOH, I looked up the Atlas threading supplement and a 10F will do 25,27,and 30. Atlas for the win! But you shouldn't need a 32T gear to do this.?

This has piqued my curiosity—what equipment used 27tpi? It must have been common enough somewhere b/c I just googled it and found it's stupid easy to get 3/4-27tpi taps and dies. Not even that dear, really, the tap is under $25.

Tim in VT

On Tue, Feb 28, 2023 at 11:06 PM, OldToolmaker wrote:

Given the high price of vintage Unimat thread masters, some thought might have to be given
into machining some thread masters to order.

I'm not sure it would be easy to set up many modern lathes to cut 27 tpi. Not sure about some of the older ones either. I'll have a look at our old (1950s vintage) Cardiff to see if that can do it, and how much hassle it would be.

Given the high price of vintage Unimat thread masters, some thought might have to be given
into machining some thread masters to order.

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Hi Gang:

In Trade School they recommended facing from the outside to the center. The rationale is if you start in the center and one corner is high, it will be too heavy to finish the cut. Light cuts are the way to go on a Unimat, the parts are small and the cuts are usually short.

Do get the proper Tommy Bars, and keep the cuts light.

Carl.