Quick Change Tool Post

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Winander
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Quick Change Tool Post

Postby Winander » Mon Jan 24, 2022 3:39 pm

Following the recent discussion on the above on Jeremy Suter's thread on Tips and Tricks in Machine Tool Practice viewtopic.php?f=132&t=6350&start=100#p88210 I decided to get one, a cheap one.

I have a Sherline lathe that uses a fixed toolpost where the height of the tool tip is adjusted using crescent shaped packing under the tool. The tools are 1/4". It is a fiddle to set the height accurately and must be done each time the tool is changed.

I purchased one of these from Banggood https://uk.banggood.com/Mini-Quick-Chan ... rehouse=CN that currently retail at £34.39. It has 945 reviews the vast majority of which are positive, although some, or all, could be fake. It has been supplied for a number of years and I thought the expenditure was worth the risk. It arrived surprisingly quickly; the packaging had a UK return address.

It comes with four tool holders, two for regular square tools, one for a parting off blade and one for a boring bar. Extra regular holders are available for £6.86. The holders are height adjustable using a thumbscrew and locking nut. Two cap screws are supplied as alternatives to anchor the holder to the cross slide, M8 and M10. These were no use to me as the Sherline uses a 10-32 UNF (3/16" =~5mm) cap screw. Being American it is made to imperial dimensions. Reducing the size of the screw meant that a new central sleeve that holds the body to the cross slide had to be made, so a chunk of aluminium was purchased and turned. Whilst it was not at all necessary, I bored out the outer sleeve (with the cam mechanism that locks the dovetail) as it was clearly not round and just because I have never bored anything before (stop sniggering at the back). I later found that I needed to bore the inner sleeve as my tailstock chuck would not take a drill large enough to provide relief for the T-nut.

To be frank this is not a precision made component and is all aluminium which may not suit everyone, although for our purposes, I am sure it will suffice. The main block is the same height as the original Sherline part although it is slightly fatter and overhangs the cross slide a little. The base is 39mm square and it overhangs 3.5mm but fastens down very securely. The tool holders are more loose in the dovetails before being locked than I would like, but lock securely. I suspect that the real test is if the tool is presented in exactly the same position if the holder is removed and replaced. I cannot answer that as I have hardly used it. The sheer convenience of it being so simple to adjust the height of the tool is a big win for me. There is also the potential to modify a tool holder so that I can hold work on the cross slide and adjust its height for drilling operations as I don't have a pillar drill or mill.

The pictures on the Banggood site should give you an overview of what you get and I will post some dimensions later today. If you have any questions, feel free to ask. You can ask personally at the Virtual Group's zoom meeting on Wednesday viewtopic.php?f=3&t=7633#p85791
Richard Hodgson
Organiser Scalefour Virtual Group. Our meeting invitation is here.

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Winander
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Re: Quick Change Tool Post

Postby Winander » Mon Jan 24, 2022 4:24 pm

The original Sherline tool post is 31mm square and 38mm high.

The QCT is a fair bit larger at 39mm square (ignoring the dovetails) and 38mm high. In addition the dovetail and tool holder push the tool some 19mm further out than the Sherline post where the tool is fitted within the dimensions of the post.

The regular holder is 50mm long*, 19mm wide and 25mm deep. The height adjustment allows the holder to sit on the cross slide although the screw isn't then long enough to allow the locking nut to fit. This would put the base of the tool 5mm above the cross slide. With the holder at its maximum height the base of the tool is 18mm above the cross slide. The tool slot is 13mm high and 8mm deep so there is the ability to pack up a small tool.

The boring bar holder will accommodate a 9.5mm bar.

The parting blade holder will accommodate a blade 15mm deep at the extreme and the 'shelf' it sits on is 2mm wide.

If you need to make the inner sleeve to hold a smaller screw, I would suggest aluminium rod of an absolute minimum of 20mm diameter as the sleeve is 17mm in diameter. The cap on the end is largely decorative if a small screw is used. It is critical the the length of the sleeve is accurately machined so that it does not bind the cam operating mechanism, i.e. the outer sleeve, when the post is screwed down. The effective length of mine (i.e. not including the cap) is 45mm which gives a 0.5mm gap above the inner sleeve.

Please ask if you require any further information.

*All the holders are 50mm long.
Richard Hodgson
Organiser Scalefour Virtual Group. Our meeting invitation is here.

nigelcliffe
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Joined: Mon Jul 21, 2008 8:31 am

Re: Quick Change Tool Post

Postby nigelcliffe » Mon Jan 24, 2022 5:04 pm

There are lots of similar-ish quick change tool posts. I have one which is 25-ish years old on my Cowell, which probably came from Chronos.

I find them to be sufficiently accurate on swapping tools(*). I align them by setting the tool below centre height, then tighten the locking mechanism to "almost tight", then use the adjusters to drag the tool upwards to centre.
I've modified a few of the holders I have for various other jobs.

The main downside is one you mention above - the tool is pulled off-centre of the standard fixing point. On a small lathe that can lead to some rotation pressure on the slides (particularly the cross-slide). So, watch if doing harder cuts that it isn't twisting everything.


(*) I often have several tools setup for use, and will be swapping sometimes more often than once a minute on a repetitive job. Similarly I have several drill chucks for the tailstock for the same reason, saves the faff of changing bits for repetitive jobs.

- Nigel

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Hardwicke
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Re: Quick Change Tool Post

Postby Hardwicke » Sun Jun 25, 2023 4:19 pm

I'm after a Myford Series 10 (for an ML10) quick change toolpost Part No 78256. The problem is the company that acquired the Myford band doesn't make it anymore and the Part 78175 they do make restricts the tool bit size to 1/4 inch (6.35mm). Without having my P4 tool to hand;
1) where can I get a 78256?
2) what size in the Scalefour tool?
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".

David Knight
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Joined: Sun Jul 20, 2008 6:02 pm

Re: Quick Change Tool Post

Postby David Knight » Sun Jun 25, 2023 8:51 pm

Can’t help with the tool post but the S4 tool bit is 6mm square.

HTH

David

Clive Impey
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Joined: Sat Aug 15, 2009 9:09 am

Re: Quick Change Tool Post

Postby Clive Impey » Mon Jun 26, 2023 8:54 am

Hello Michael, I also have an ML10 and have been able to get spare parts from a company called Myfordstuff. If you Google ' myford stuff Woodhall Spa' you should get their contact details including a telephone number.

Clive.

Terry Bendall
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Re: Quick Change Tool Post

Postby Terry Bendall » Mon Jun 26, 2023 2:46 pm

A useful source of spares for Myford and other machines is
Home and Workshop Machinery
144 Maidstone Rd, Sidcup DA14 5HS
http://www.homeandworkshop.co.uk/
020 8300 9070

Terry Bendall

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Hardwicke
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Re: Quick Change Tool Post

Postby Hardwicke » Fri Jun 30, 2023 5:28 am

Thanks Clive and Terry. I've looked at both but nothing available at the moment. David, I might get the 78125 instead but I do have some larger bits
Ordsall Road (BR(E)), Forge Mill Sidings (BR(M)), Kirkcliffe Coking Plant (BR(E)), Swanage (BR (S)) and Heaby (LMS/MR). Acquired Thorneywood (GNR). Still trying to "Keep the Balance".


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