Gear Cutter

[ford34/2]

ime on the same hunt Stan but added complication as my Harrison is Metric..

Don't you mean metric threads? There was a discussion on the list a while ago regarding that. Apparently the difference in real life between the 63 and the 127 is inconsequential. Leadscrew wear would likely throw more error into the thread than the 63/127 aspect would.

ROOFMAN:: are you after a 63T or the 127T I`ll keep my eye open, over a few years never ever seen a 63 for sale but several 127.

The Harrison Lathe both myself and John (doubleboost) have is the 140 Model with the 36 speed Norton gearbox, easily identified by the 3 selector knobs on the gearbox. The Lathe is an all Metric machine, Dials and Harrison screwcutting information plate are all in Metric.
The introduction of the 63 translation gear allows the gearbox with the correct changewheel set up to cut imperial threads, with a range from 4 to 60 TPI. To cut this whole range, one changewheel needs to be swapped on the train. So basically 5 changewheels will cut the 4-60 TPI range, although only 4 are in use at any one time.

I dont see any problem reversing this process to cut Metric threads on an imperial lathe. Using a 63t, or a 127t changewheel -- Not having an imperial lathe I cant test drive my theory. Now a 127T is a big change wheel and comes in at over 91/4" -- can it fit into any banjo setup you have, ?????????????

Stan

 

[roofman]

ROOFMAN:: are you after a 63T or the 127T I`ll keep my eye open, over a few years never ever seen a 63 for sale but several 127.

The Harrison Lathe both myself and John (doubleboost) have is the 140 Model with the 36 speed Norton gearbox, easily identified by the 3 selector knobs on the gearbox. The Lathe is an all Metric machine, Dials and Harrison screwcutting information plate are all in Metric.
The introduction of the 63 translation gear allows the gearbox with the correct changewheel set up to cut imperial threads, with a range from 4 to 60 TPI. To cut this whole range, one changewheel needs to be swapped on the train. So basically 5 changewheels will cut the 4-60 TPI range, although only 4 are in use at any one time.

I dont see any problem reversing this process to cut Metric threads on an imperial lathe. Using a 63t, or a 127t changewheel -- Not having an imperial lathe I cant test drive my theory. Now a 127T is a big change wheel and comes in at over 91/4" -- can it fit into any banjo setup you have, ?????????????

Stan

Stan ile see whats on the machine atm,i dont have any spare wheels at all but remember making a note when i bought it that i had no facility to cut run of the mill threads..cheers

 

[ford34/2]

The screwcutting information plate is a copy of the double sided metric one on the front of the box, No its not a Harrison one, it took as long to do as sorting out the gear selection. Its also searchable on Google.
https://plus.google.com/107784601559913192023/posts/UkdFSF2yrFP

Heres some pics of the Metric coarse and fine and a copy of the homemade imperial one.

Stan

 

[MattF]

I'd never thought about it 'til you mentioned it Stan, but logic does dictate it should work in both manners; imperial to metric, metric to imperial.

 

[doubleboost]

I'd never thought about it 'til you mentioned it Stan, but logic does dictate it should work in both manners; imperial to metric, metric to imperial.

It works both ways my last lathe was imperial
Same set up to cut metric

 

[roofman]

never thought how handicapped i am with this metric harrison 11"...all i have is a 120 on the bottom...intermediate of 70 and a top of 20. giving me the only option of a pitch of 0.5...to do any usefull thread cutting i need a 100,80,60,55,50,45. Maybe this £425 bargin was,nt so much of a bargin without a set of metric change wheels

 

[AndyStobbs]

never thought how handicapped i am with this metric harrison 11"...all i have is a 120 on the bottom...intermediate of 70 and a top of 20. giving me the only option of a pitch of 0.5...to do any usefull thread cutting i need a 100,80,60,55,50,45. Maybe this £425 bargin was,nt so much of a bargin without a set of metric change wheels

We are in similar boats, and locations. I have the facilities to machine blanks, as do you. I have a bloody gert milling machine for gear cutting, no dividing head as of yet though. I think between us we can knock up some gears for ourselves on a budget.

 

[AndyStobbs]

Surely your gearbox enables more pitches though Roofman?

 

[roofman]

Surely your gearbox enables more pitches though Roofman?

dont have a gearbox Andy...only 3 speeds on my lead

 

[roofman]

We are in similar boats, and locations. I have the facilities to machine blanks, as do you. I have a bloody gert milling machine for gear cutting, no dividing head as of yet though. I think between us we can knock up some gears for ourselves on a budget.

i have a massive rotary table with a fixed 200mm chuck but can only sit on the horizontal plane

 

[AndyStobbs]

Could be set up in the horizontal and feed the table up to take the cut rather than across.

 

[lchris21]

14 1/2 deg 14 DP I can only find a full set in China

half way down the page under DP gear cutters??.....

http://www.homeandworkshop.co.uk/miscu200.htm?56751

Don't know if they are any good???

 

[roofman]

Could be set up in the horizontal and feed the table up to take the cut rather than across.

well thats it then..sorted

 

[doubleboost]

half way down the page under DP gear cutters??.....

http://www.homeandworkshop.co.uk/miscu200.htm?56751

Don't know if they are any good???

They are the ones but all missing the number 2 that is the one you need to cut 63

 

[nick952]

Only place I could find one was in the U.S.

http://www.toolmex.com/Products/BrowseResults.aspx?CatID=230&&parent=&pageno=19&cat=230

Item Number: 5-860-186

 

[doubleboost]

Only place I could find one was in the U.S.

http://www.toolmex.com/Products/BrowseResults.aspx?CatID=230&&parent=&pageno=19&cat=230

Item Number: 5-860-186

That's the one

 

[nick952]

Just dug a bit deeper and these guys should be able to help:- http://www.crtools.co.uk/involute-gear-cutters-sheffield.html

 

[doubleboost]

Just dug a bit deeper and these guys should be able to help:- http://www.crtools.co.uk/involute-gear-cutters-sheffield.html

Thanks
I have sent them a email

 

[Brad93]

@doubleboost

Did you ever make a 63T gear?

 

[grim_d]

Note the Date, but contact Alan and double check.Any other info is in this E mail copy.
Stan

From: "alanhearsum@btinternet.com" <alanhearsum@btinternet.com>
To: Stan Gordon
Sent: Sunday, 15 September 2013, 15:45
Subject: Re: Want a 63T tooth gear-Harrison 140
Hello Stan
Glad you made a bid on the gear on ebay. I shall start machining the 63 tooth gear on Monday 16th. I will then take it to the gear cutters on Tuesday. Normally they take a couple of days so you should have it posted to you next week. I will weigh for postage and let you know total cost. Blank will be £10+Machining £10 + Gear cutting probably £15 = £35 + postage.
I will keep you informed cash will be alright providing you wrap in cardboard. I will let you know cost it should not vary that much from this quote.
Regards
Alan

I could make you one and get it gear cut for you in Sheffield. I guess you know that an 127 tooth gear 14dp x 14.5 degree pressure angle x 5/8 inch face width x 5/8 inch bore is 9.274 inches outside diameter. Does the Drummond have room to work with such a large gear? Let me have your email address if you are interested.
Best of luck
Alan Hearsum, Rats Castle, Dale End, Bradwell, Hope Valley, Derbyshire S33 9HP.

I've been getting emails from this "Alan hearsum" today asking to buy his neice Amazon vouchers. Think his email must have been hijacked...anyone else?