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View Full Version : Mounting a TP grinder



loose nut
12-28-2008, 06:15 PM
I bought a small TPG (the smaller 110 V model) from Little Machine Shop a few month's back and I finally decided it was time to mount it. It's going on my older 9 x 20" lathe ( a Chinese copy of the 8 x 18" Enco lathe) and the advert for it says that it will fit an 7, 8 or 9" lathe. I can't see how it would go on the 7 x 14" lathes because it will be a tight fit on my 9.

LMS have a drawing of a bracket for mounting the TPG on some lathes but it looks like there would be a lot of overhang and weight suspended from the tool post. Is this a problem? Since the feed load is small when taking light cuts would this be stable enough to prevent problems.
Most pictures I have seem show TPG's mounted with little support so maybe it's not a problem.

Any ideas. Tifie I know you mounted one, any thoughts.

oldtiffie
12-28-2008, 09:09 PM
Hi loose nut.

If you can do without taper grinding using your compound rest - take it off and mount the TPG on the cross-slide. If you have a taper-turning attachment for your lathe you are "laughing".

My biggest problem was fouling the tail-stock quill if grinding between centres. I was going to modify my TPG to take 100mm (4") wheels. I could do quite well by turning the TPG clockwise on the cross-slide and dressing the wheel as it solved all or most problems other than facing (the end or a shoulder) of a job - but I just left the TPG as it was and dressed off a small "flat" on the side of the wheel and fed the TPG in until the periphery of the wheel was just clear of the cylindrical part/s of the work and then fed the carriage or compound rest (if still fitted) sideways and "side-wheeled" the face to get that nice "over-lapping arc" finish. It worked pretty well. (A "cup" wheel is even better here as it is "made" for that sort of "facing" work).

If there is no top-slide you should mount a good dial indicator on the carriage and use either the carriage hand-wheel or alternatively engage your lathe half-nuts and use the lead-screw as a compound slide lead-screw. You can do this by disengaging your gear train and put a spanner on the nut on the end of the lead-screw drive and use the spanner and the indicator - works very well. My lathe is a "3-in-1" and has a calibrated dial and hand-wheel on the tail-stock end of my lead-screw - very handy!! There are several members here who have the same basic lathe with the same feature - from "BusyBee" (Canada).

I scrapped my TPG mount as I had another need for the bits from it. I have a universal grinder now that is an excellent cylindrical grinder as well as a surface and tool & cutter grinder.

I was never happy about grinding on my lathe. I contemplated mounting the TPG on my HF-45 square column mill "Y" (cross-slide) or "Z" (vertical dove-tail) and mounting my mini-lathe on the mill table - but it was a bit "Heath Robinson" - who I am sure either lives on this site and/or was a dedicated "HSM-er"!!! - and I didn't like grinding on the mill either.

http://images.google.com.au/images?hl=en&q=heath+robinson&um=1&ie=UTF-8&sa=X&oi=image_result_group&resnum=4&ct=title

http://en.wikipedia.org/wiki/W._Heath_Robinson

http://en.wikipedia.org/wiki/Bill_the_Minder


Oh yes.

The TPG I have is the one that has the drill chuck on the "other end" of the spindle. It is reversible and is surprisingly accurate for a drill chuck. It only runs at "half speed" (It was intended for milling) but it did open up a few more options for mounting on the lathe or mill.

oldtiffie
12-28-2008, 09:19 PM
I bought a small TPG (the smaller 110 V model) from Little Machine Shop a few month's back and I finally decided it was time to mount it.

.................................................. ........
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Any ideas. Tifie I know you mounted one, any thoughts.

Well, I did smile when I re-read your post.

As an ex-sailor (OZ Navy where I specialised in gun-mountings and effective use of "weapons") I had visions of me "mounting" a TPG.

Hence reference to the inimitable Mr. Heath Robinson - but alack and alas (NO!! - not a "lass"!!) to no avail.

I shall further consider and contemplate making a suitable contraption/device in accordance with the principles annunciated by Mr. H. R.

"Tiffies folly"?? - I guess so.

barts
12-28-2008, 10:11 PM
I bought a small TPG (the smaller 110 V model) from Little Machine Shop a few month's back and I finally decided it was time to mount it. It's going on my older 9 x 20" lathe ( a Chinese copy of the 8 x 18" Enco lathe) and the advert for it says that it will fit an 7, 8 or 9" lathe. I can't see how it would go on the 7 x 14" lathes because it will be a tight fit on my 9.

LMS have a drawing of a bracket for mounting the TPG on some lathes but it looks like there would be a lot of overhang and weight suspended from the tool post. Is this a problem? Since the feed load is small when taking light cuts would this be stable enough to prevent problems.
Most pictures I have seem show TPG's mounted with little support so maybe it's not a problem.

Any ideas. Tifie I know you mounted one, any thoughts.

I think the gravity load + grinding contact force (small) are tiny compared to normal cutting tool forces. You will want to make sure the bracket is stiff enough that the natural frequency doesn't produce any appreciable chatter marks...

Teenage_Machinist
12-28-2008, 11:17 PM
Also make sure that it does not deflect.

oldtiffie
12-28-2008, 11:25 PM
Bart.

The grinder itself is quite good for the price really.

Any problems in regard to finish are to do mainly with the irregularities of the 20mm bore wheels provided which are quite a bit "out of balance" and that the wheel hubs have no provision for "balancing". I was going to make new hubs to suit the range/s of wheel bores available/needed but never got around to it.

But in terms of "bang for buck" its hard to beat.

loose nut
12-29-2008, 10:55 AM
OK Tifie I reread it too, poor choice of phrasing and I'm going to have disturbing visions of that in my head for a long time, sorry, but you know what I really meant.

The reason I'm trying to "place" the TPG on my older 9" lathe is, I won't let it anywhere near my newer 13" lathe which could be easy to "arrange" the TPG to the proper center height.
unfortunatly I'm going to abandon the top slide, there just isn't enough room there to get the center height right. I have no idea how one of these TPG's could be "erected" on a 7" (not counting Myfords of course) lathe as LMS claims.