Think iv found a cure to my problem with parting off

[Steve_S]

Hi Guys
Iv all ways had problems with parting off watched lots of videos on YouTube tried different ways of sharping parting tool blade all with no luck lots of juddering I had tried all sorts slow the speed down speed it up raise tool up set it low etc ect
But now think iv found the problem
I had always thought the cross slide locking screw at the rear on my model were a pain to get at so set it up in mill and drill some new holes at the front, was making a tapping tool to day needed to part off some stainless steel and it worked like a charm so i recon the cross slide was tipping at the back due to no support.

IMG_1493.JPG (650.05 KiB) Viewed 7253 times

IMG_1498.JPG (646.39 KiB) Viewed 7253 times

Had a Bugger moment to day also, I thought these were made of steel but seems not looks like cast iron cant say I was leaning on it that hard

IMG_1496.JPG (485.19 KiB) Viewed 7253 times

[Pete.]

Looking at the picture with the fishtail gauge in it, it looks like your compound has taken a bit of a beating at some time and raised the edge right on the corner. I bet that the slide is only contacting on a couple of points, and the lock screw you fitted has given it some support. The proper cure for it would be to fix the slideway by scraping (or even stoning) the high spot out then checking with blue.

[rpwilson]

Sorry, I'm not sure what you have done here. From the photos it looks like you have drilled and tapped a couple of extra holes in the cross slide, in more accessible positions, to secure the topslide. If so, how does that stop the cross slide from tipping up at the back?
I know this is going to sound like heresy, but from your photo of the broken toolholder, I presume you are using a QCTP for holding the parting tool?
I've always thought that because these have the tool overhung, they are a much less rigid set up than the older style toolposts, and it might be worthwhile keeping a parting tool set up in a 4 way toolpost, and just swap toolposts when required.
Anyway, I'm pleased that you seem to have solved the problem.
I thought those toolholders were steel, as well. Maybe the original Dickson ones were, and the modern copies are not?

[Steve_S]

Hi Pete and rpwilson

It would seem I have not explained the problem correctly and im getting my cross slide and top slide confused. I'm no engineer or machinist but a builder who like to make stuff
Pete you are right the cross slide has took a beating at some point before i got the lathe.
rpwilson "it looks like you have drilled and tapped a couple of extra holes in the cross slide" you are correct it was at first to get them "in more accessible positions"
But a side benefit is I can now part off.

Not the best drawing but hope you guys get the gist of what I mean. I had a look at a later model and the top slide has 3 locating screws so possibly the way mine was made was a design fault rectified on later models

[rpwilson]

I'm glad you solved your parting off problem, but am mildly curious regarding the lathe itself. It has a different arrangement for fixing the topslide to any Denford I've seen, and seems to have the half nut lever on the left of the apron, and also has a tee slot in the front wing of the saddle. Is it in fact a Denford, if so, what model?

[Steve_S]

Code: Select all

I'm glad you solved your parting off problem, but am mildly curious regarding the lathe itself. It has a different arrangement for fixing the topslide to any Denford I've seen, and seems to have the half nut lever on the left of the apron, and also has a tee slot in the front wing of the saddle. Is it in fact a Denford, if so, what model?

Hi rpwilson
see this post re lathe viewtopic.php?f=50&t=4634